1、-ASTM D2272 85 E 0759510 0024798 I K-AMERICAN SOCIETY FOR TESTING AND MATERIA&1916 Race St.,Philsddphia,Pa.19103 Rwrinted from the Annual Book of ASTM Standards,Copyright ASTM If not lined in the current combined index,will mr in the next edition.Standard Practice for COMPRESSION MOLDING TEST SPECIM
2、ENS OF SYTRENE-BUTADIENE MOLDING AND EXTRUSION MATERIALS This standard is issued under the xed designation D 2292;the number immediately following the designation indicates the year of original adoption or,in the ose of revision,the year of last revision.A number in parentheses inclkates the year of
3、 last reapproval.A superscript epsilon(e)indicates an editorial change since the last revision or rcapproval.1.scope 1.1 This practice covers the compression molding of plaques or test specimens of styrene-butadiene molding and extrusion materials as defined in Specification D 1892.1.2 The vaiues st
4、ated in S I units,as detailed in Standard E380,are to be regarded as the standard.1.3 This standard may involve hazardous ma-terials,operations,and equipment.This standard does not purport to address all of the safty prob lems associated with its use.It is the responsibii-ity of whoever uses this st
5、andard to consult and establish appropriate safty and health practices and determine the applicability of regulatory limi-tations prior to use.2.Applicable Documents 2.1 ASTM Standards:D 6 18 Methods of Conditioning P l a s t i c s and Electrical Insulating Materiais for Testin?D 1693 Test Method fo
6、r Environmental Stress-Cracking of Ethylene Plastics3 D 1892 Specification for Styrene-Butadiene Molding and Extrusion Materials3 E 380 Standard for Metric Practice4 4.Apparatus 4.1 Molds:4.1.1 Molding Chase-A picture-frame”compression-molding chasz having a blanked-out area of suitable size(Note 1)
7、and capable of producing a plaque 3.2 f 0.13 mm(0.125 f 0.005 in.)thick.Dimensions are shown in F i g.1 of Test Method D 1693,for a molding chase to produce 152.4 by 152.4-mm(6 by 6-in.)plaques.NOTE 1-A 1 5 2.4 by 152.4-mm(6 by Gin.)blanked-out section has been found satisfactory.4.1.2 Molding Plate
8、s-Two polished chro-mium-plated ferrotype piates(dimensions shown in Fig.1 of Test Method D 1693)such as used i n photography,at least 1.0 mm(0.040 in.)thick,and of adequate surface area to cover the molding chase.4.1.3 CavityMol&-Acavity-type flash mold capable of producing a plaque of the specifie
9、d dimensions may be used.Alternative test speci-mens may be molded to their finished dimen-sions,exclusive of the notch for impact strength,in a multi-cavity compression-molding chase.4.1.4 Aluminum FoilSame size as molding plates(4.1.2)and O.1 mm(0.004 in.)thick.3.Significance and Use5 I This pract
10、ice is under the jurisdiction of AsTM Committee B20 on Plastics and is the dinct responsibuity of Sulmmmitlet 20.09 on Specimen-tion.,yg!E;:edition 2292-68(1981),3.1 The method by which samples are molded influences the mechanical properties of the spec-imen.The Izod impact-test vaiues for compres-s
11、ion-molded specimens are known to be lower,but were less subject to variation than are values for injection-molded specimens.There is evi-dence of a relationship between the properties of compression-molded specimens and those of ex-truded specimens.2 u a l BwkofASTMSlandardF,Vd 08.01.:$m$:y:$S A md
12、y of mmp-on-molding temperature erects on obtained from 6 high-impact polyStyre=pmperiies ASTM H e a d q u a r t e r s Request RR:D20-1003.ofdeNd drawiw for comdo,ofthis is available at a nominal cost f r o m ASIU Headquarters.NOTICE:This standard has either been superseded and replaced by a new ver
13、sion or discontinued.Contact ASTM International(www.astm.org)for the latest information.ASTM D2292 55 W 0759530 0024999 3 W(CIiI,4.2 Press-The hydraulic press shli be such that the molding pressure on the specimen can be maintained at the value,and within the tol-erances,prescribed.4.3 Heating Syste
14、ms-Any convenient method of heating the press platens or molds may be used,provided that the heat source is constant enough to maintain the mold tempera-ture within f2C(f5F).5.Conditioning 5.1 Conditioning-Condition the test s p i-mens at 23+-2C(73.4&3.6F)and 50 f 5%relative humidity for not less th
15、an 40 h prior to test in accordance with Procedure A of Methods D 618,for those tests where conditioning is re-quired.In case of disagreement,the tolerances shall be f 1 C(t 1.8F)and f 2%relative humid-ity.5.2 Conditions-Conduct tests in the Stand-ard Laboratory Atmosphere of 23&2C(73.4&3.6F)and 50&
16、5%relative humidity,unless otherwise specified in the test methods or in the specification.In case of disagreement,the toler-ances shall be f l o c (f1.8F)and 22%relative humidity.6.Procedure 6.1 Be sure the mold is clean.Precondition the mold with a mold-release agent.Fluorocar-bon release agents have been found satisfactory.6.2 Place a sheet of aluminum foil on the back-up plate and place the mold on the foil sheet,This will help eliminate localized sink marks.6.3 Place a measured amount of gr