1、Designation: C 581 03An American National StandardStandard Practice forDetermining Chemical Resistance of Thermosetting ResinsUsed in Glass-Fiber-Reinforced Structures Intended forLiquid Service1This standard is issued under the fixed designation C 581; the number immediately following the designati
2、on indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by age
3、ncies of the Department of Defense.1. Scope1.1 This practice is designed to evaluate, in an unstressedstate, the chemical resistance of thermosetting resins used inthe fabrication of reinforced thermosetting plastic (RTP) lami-nates. This practice provides for the determination of changesin the prop
4、erties, described as follows, of the test specimensand test reagent after exposure of the specimens to the reagent:hardness of specimens, weight change thickness, appearance ofspecimens, appearance of immersion media, and flexuralstrength and modulus.1.2 The values stated in inch-pound units are to
5、be regardedas the standard. The values in parentheses are given forinformation only.NOTE 1This practice may also be used to evaluate other factors, suchas surfacing veils, the effect of resin additives, and fabrication variables onthe chemical resistance of the resin.NOTE 2There is no similar or equ
6、ivalent ISO standard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated 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 t
7、o use.2. Referenced Documents2.1 ASTM Standards:D 790 Test Methods for Flexural Properties of Unreinforcedand Reinforced Plastics and Electrical Insulating Materi-als2D 2563 Practice for Classifying Visual Defects in Glass-Reinforced Plastic Laminate Parts3D 2583 Test Method for Indentation Hardness
8、 of RigidPlastics by Means of a Barcol Impressor3D 2584 Test Method for Ignition Loss of Cured ReinforcedResins33. Significance and Use3.1 The results obtained by this practice shall serve as aguide in, but not as the sole basis for, selection of a thermo-setting resin used in an RTP structure. No a
9、ttempt has beenmade to incorporate into the practice all the various factors thatmay enter into the serviceability of an RTP structure whensubjected to chemical environments. These factors may includestress, different resin-to-glass ratios, and multiple veils.4. Apparatus4.1 Hardness Testing Instrum
10、entThis shall be as de-scribed in Test Method D 2583.4.2 Flexural Properties Testing Apparatus, in accordancewith Test Methods D 790.4.3 Thickness MeasurementA micrometer suitable formeasurement to 0.001 in. (0.025 mm).4.4 Containers, of sufficient size, capacity, and inertness toallow total immersi
11、on of reinforced thermosetting plasticspecimens in the specific corrosives chosen for testing. Thesecontainers shall, when necessary, be capable of maintainingliquid levels of volatile solutions, that is, solvents. This can beaccomplished by the use of reflux condensers.4.5 Heating ApparatusAconstan
12、t temperature oven, heat-ing mantle, or liquid bath capable of maintaining temperaturewithin range of 64.0F (62.2C). Proper precautions shouldbe taken if the corrosives selected are flammable liquids.4.6 Analytical Balance, suitable for accurate weighing to0.001 g.1This practice is under the jurisdi
13、ction ofASTM Committee D20 on Plastics andis the direct responsibility of Subcommittee D20.23 on Reinforced Plastic PipingSystems and Chemical Equipment.Current edition approved July 10, 2003. Published August 2003. Originallyapproved in 1965. Last previous edition approved in 2000 as C 581 00.2Annu
14、al Book of ASTM Standards, Vol 08.01.3Annual Book of ASTM Standards, Vol 08.02.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5. Reagents5.1 The test media shall consist of the reagents or solutionsto which the RTP laminates are to
15、be exposed.6. Test Specimens6.1 Standard LaminatesPrepare standard fiber-reinforcedlaminates using identical reinforcement in all of the laminates.The laminates shall be constructed of the following materials:6.1.1 Surfacing Mat (Veil)A thin mat of fine fibers usedprimarily to produce a smooth, resi
16、n-rich surface on a rein-forced plastic. The surfacing veil helps determine the thicknessof the resin-rich layer, reduces microcracking and provides anon-wicking chemicallyresistant layer. The surfacing veilshall be compatible with the resin, and manufactured withuniform fiber distribution and non-b
17、undled fibers. The dry veillayer(s) shall be a minimum 10 mils in thickness and producea 10 to 15 mil resin-saturated veil layer per 10 mils of dry veil.To eliminate the surfacing veil as a variable in corrosion tests,prepare each laminate within a test group with the samesurfacing veil.6.1.2 Choppe
18、d Strand MatType E glass fiber with sizingand binder compatible with the resin. Other glass fiber com-positions may be used but should be considered as variables forcomparison to the standard.6.1.3 ResinCatalyzed and promoted in accordance withthe resin manufacturers recommendation.NOTE 3Fillers, su
19、ch as antimony trioxide for improved fire retardancyor thixotropes for viscosity control, may be added, but may detract fromthe corrosion resistance of the test laminate.6.2 Dimensions and General PropertiesThe laminatesshall conform to the required dimensions and general proper-ties of 6.2 and be f
20、abricated in accordance with 6.3.6.2.1 Laminate SizeA suitable laminate size has beenfound to be 26 by 33 in. (660 by 838 mm) after trimming. Thislaminate size is not restrictive and other dimensions may beused.6.2.2 ThicknessThe thickness of the cured standard lami-nate shall be between 0.120 and 0
21、.140 in. (3.05 and 3.56 mm).6.2.3 Reinforcement ContentThe glass fiber and bindershall be 4.73 6 0.47 oz/ft2(three layers of 1.5 oz/ft2choppedstrand mat 4.5 oz/ft2having a nominal binder content of 3.5 %and two layers of 10 mil surfacing mat 0.23 oz/ft2having anominal binder content of 7 %)determine
22、d by preweighingthe materials prior to construction of the laminate. This isequivalent to 23.6 weight % (12.5 volume %) glass fiber whenusing a resin having a cured specific gravity of 1.15. Such alaminate will have a thickness of 0.125 in. (3.18 mm). The useof resins having different specific gravi
23、ties will result indifferent weight percentages of glass fiber, but the volumepercentage of glass fiber will remain the same. When usingsynthetic organic fiber surfacing veil, the glass content shall be4.50 6 0.45 oz/ft2( three layers of 1.5oz/ft2chopped strand mathaving a nominal binder content of
24、3.5 %).6.2.4 HardnessThe hardness shall be at least 90 % of thatof a fully-cured clear casting of the resin, or of a similarlyconstructed laminate as defined by the resin manufacturer.Hardness shall be determined in accordance with s4.1.Itshould be noted that the use of synthetic veil will result in
25、significantly lower hardness values. The hardness value willvary with the type of resin and number of plies of syntheticveil. The resin manufacturer should be contacted for theallowable Barcol hardness value of a laminate containingsynthetic veils with the specific resin.6.2.5 Laminate ConditionThe
26、laminate shall meet Accep-tance Level I of Table I of Practice D 2563.6.3 Fabrication of Standard LaminateThe sequence oflay-up shall be as follows:6.3.1 Apply catalyzed resin and a 10-mil (0.25-mm) surfac-ing mat on a flat surface covered with plastic release film4ortreated with a suitable release
27、agent and roll to distribute resin.NOTE 4The following formula may be used as a guide to determinethe total weight of resin to be used. This is equivalent to 12.5 volume %glass fiber in the laminate. Grams resin equals grams glass fiber materialper 6.2.3 times 2.82 G. Where G equals specific gravity
28、 of cured resin.Excess resin may be used due to loss by adhering to mixing containers,rollers, and other factors.Asuggested amount of excess resin is 10 to 15 %by weight.6.3.2 Follow with three plies of 1.5 oz/ft2chopped strandmat and resin. Roll after each ply to distribute and wet-out thechopped s
29、trand mat. Rolling with a serrated roller may be doneafter each ply to remove entrapped air but shall be done inaccordance with 6.3.4. The mat weight shall be within 65%of1.5 oz/ft2upon weighing the full 26 by 33-in. cut (660 by838-mm) piece, (or other full dimension used, 6.2.1.).NOTE 5Chopped stra
30、nd mat should be cut so that the 26-in. dimen-sion is across the width of the roll and the 33-in. dimension is along themachine direction of the mat. Mat weight variation will most commonlyoccur across the width of the mat. If a wide roll of mat, 52 in. (1320 mm)or greater, is used, the two plies of
31、 mat should be placed in the laminatesuch that the center cut of one ply is placed over the outside edge of thesecond ply. If narrower width mat is used, the second ply should bereversed 180 in the machine direction and laid on top of the first ply tominimize weight variations.6.3.3 Follow with a 10
32、-mil (0.25-mm) surfacing mat as in6.3.1.6.3.4 Remove the air by rolling over the surface with aserrated metal or plastic roller. Take care not to expel enoughresin to raise the glass content above the permissible maxi-mum. The laminate is considered within the range of allowablelevels of resin and g
33、lass if the thickness of the laminate iswithin 0.120 and 0.140 in. (3.05 and 3.56 mm), as described in6.2.2.6.3.5 After the lay-up is completed, cover the laminate witha plastic release film to prevent air inhibition or to provide auniform smooth glossy surface, or both. Carefully smoothdown to remo
34、ve entrapped air.NOTE 6The application of the release film may be accomplished byany convenient method. Regardless of how it is applied, it is critical thatany entrapped air between the film and the laminate be entirely removed.One method of application is done by previously wrapping the film around
35、a metal rod. Starting at one edge of the laminate, slowly unroll the filmfrom the rod, keeping a bead of resin ahead of the rod as you cross thelaminate. Any entrapped air remaining can be removed by rubbing atongue depressor across the release film surface. Carefully pull the film43 to 5 mil standa
36、rd oriented polyester film (MYLARtTypes A, S, or D, orMELINEXtTypes S, 0, or 442) has been found suitable for this purpose.C581032taut and fasten at the edges to prevent wrinkling of the film. Placing stops(neoprene has been found to be suitable) around the edges of the laminateand passing a heavy m
37、etal roller over the laminate helps to insure uniformcontrolled thickness.6.3.6 Cure as recommended by the resin manufacturer. Thecure schedule shall be reported.6.3.7 Trim edges as required.6.4 Record of Standard Laminate ConstructionRecord theproperties of the standard laminate as follows:6.4.1 Ha
38、rdnessDetermine Barcol hardness on the strip asdescribed in 6.2.4 in accordance with Test Method D 2583.6.4.2 Laminate ConditionsVisually examine the laminate.The laminate shall meet Acceptance Level I of Table 1 ofPractice D 2563.6.4.3 If the laminate meets the requirements of this speci-fication,
39、retain the laminate sections for preparation of testspecimens.NOTE 7The major criteria for accepting a laminate is thickness andnot glass content. If glass content is desired, cut eight 1 by 1 in. specimensfrom the center of the laminate and test in accordance with Test MethodD 2584.6.5 Individual T
40、est Specimens:6.5.1 Specimens for immersion in test solutions shall beapproximately 4 by 5 in. (101.6 by 127 mm), cut from thestandard laminate.6.5.2 Identity of specimens shall be maintained by suitablemeans.6.5.3 Cut edges and drilled holes, if used for suspension,shall be sanded smooth and coated
41、 with paraffinated resin.6.5.4 The number of specimens required is dependent on thenumber of test solutions to be employed, the number ofdifferent temperatures at which testing is performed, and thenumber of test intervals. In addition, at least two 4 by 5 in.(101.6 by 127 mm) specimens shall be ava
42、ilable for test (see7.4) following the curing period, prior to immersion.7. Procedure7.1 Measurement of SpecimensImmediately following thecuring period, measure the thickness of the specimens to thenearest 0.001 in. (0.025 mm) at the geometric center of each ofthe intended 1 by 3 in. (25.4 by 76.2 m
43、m) specimens that willbe cut for flexural tests after the completed exposures. Measurethe weight of the specimens to the nearest 0.01 g. Thesethickness and weight measurements shall also be used forcomparison against thickness and weight measurements afterthe completed exposures.7.2 ExposureFollowin
44、g the curing period, as specified in6.3.6, prior to immersion, record a brief description of the colorand surface appearance of the coupons and the color and theclarity of the test solution. The total number of coupons percontainer is not limited except by the ability of the container tohold the cou
45、pons without touching each other or the container.The coupons must always be completely immersed. Couponsshould be vertical, parallel, and spaced a minimum of 0.25 in.(6.35 mm) apart. There should be a minimum of 0.50 in. (12.7mm) between coupon edges and the container or the liquidsurface. Place th
46、e closed container in a constant temperatureoven adjusted to the required temperature or in a suitablyadjusted liquid bath. Examine the coupons after 30, 90, 180days, and one year of immersion or other time intervals asrequired to determine the rate of attack.7.2.1 Discard the test solution and repl
47、ace it with freshsolution as often as necessary to maintain original compositionand concentration.As a minimum, solutions known to be stableshould be replaced at the end of each test period.7.3 Cleaning and Examination After ExposureClean thecoupon and dry by blotting with a paper towel. Cold tap wa
48、teris normally used for specimen cleaning. If other cleaningagents are used, verify that they do not attack the resin beingtested.7.3.1 Note any indication of surface attack on a coupon, anydiscoloration of the test solution, and the formation of anysediment.7.3.2 After final blotting, immediately m
49、easure the couponthickness to the nearest 0.001 in. (0.025 mm) in the geometriccenter of each intended 1 by 3 in. (25 by 76.2 mm) specimen.Measure the coupon to the nearest 0.01g. The Barcol hardnesscan then be checked, taking an average of ten readings on eachcoupon, a minimum of 0.50 in. (12.7 mm) from the edge.7.3.3 After washing and measuring thickness, weight, andBarcol hardness, place the coupons in an air-tight polyethylenebag for conditioning or shipping as described in 7.4.1.7.4 Flexural TestingDetermine the flexural strength andmodulus for:
