Designation:D 2732–03
爱粮节粮Standard Test Method for
Unrestrained Linear Thermal Shrinkage of Plastic Film and Sheeting 1
This standard is issued under the fixed designation D 2732;the number immediately following the designation indicates the year of original adoption or,in the ca of revision,the year of last revision.A number in parenthes indicates the year of last reapproval.A superscript epsilon (e )indicates an editorial change since the last revision or reapproval.
1.Scope*
1.1This test method covers determination of the degree of unrestrained linear thermal shrinkage at given specimen tem-peratures of plastic film and sheeting of 0.76mm [0.030in.]thickness or less.This test method does not cover shrinkage from loss of solvent in some materials.
1.2This standard does not purport to address all of the safety concerns,if any,associated with its u.It is the responsibility of the ur of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to u.
N OTE 1—This document is not equivalent to ISO 11501.
2.Referenced Documents 2.1ASTM Standards:
D 618Practice for Conditioning Plastics for Testing 2D 883Terminology Relating to Plastics 2
D 1204Test Method for Linear Dimensional Changes of Nonrigid Thermoplastic Sheeting or Film at Elevated Temperature 2
E 1Specification for ASTM Thermometers 32.2ISO Standard:4
ISO 11501Determination of Dimensional Change on Heat-ing 3.Terminology 3.1Definitions:
3.1.1unrestrained linear thermal shrinkage (free shrink or shrinkage )—the irreversible and rapid reduction in linear dimension in a specified direction occurring in film subjected to elevated temperatures under conditions where nil or negli-gible restraint to inhibit shrinkage is prent.It is normally expresd as a percentage of the original dimension.
4.Significance and U
4.1As a result of the manufacturing process,internal stress may be locked into the film which can be relead by heating.The temperature at which shrinkage will occur is related to the processing techniques employed to manufacture the film and may also be related to a pha transition in the ba resin.The magnitude of the shrinkage will vary with the temperature of the film.
4.2Shrinkage of a particular material produced by a par-ticular process may be characterized by this test method by making measurements at veral temperatures through the shrinkage range of the material.
4.3Following a characterization in a particular ca,it is usually sufficient thereafter to measure shrinkage at only one lected temperature for purpos of process or quality control,or both.
5.Apparatus
5.1Constant-Temperature Liquid Bath ,capable of control-ling accurately to 60.5°C.
5.1.1The liquid for the bath should not plasticize or react with the specimens.Poly(ethylene glycol),glycerin,and water have been found to have wide applicability.
5.2Thermometer —ASTM Thermometer 1C conforming to the requirements as prescribed in Specification E 1.
英文微信号5.3Square Metal Stamp ,100by 100mm,with engraved arrow indicating machine direction of film and stamp pad and ink.(The ink should not be soluble in the bath liquid.)
N OTE 2—A metal die or template (100by 100mm)can be ud instead of the square metal stamp.
5.4Free Shrink Holder —A holder designed for test of a single specimen,such as that shown in Fig.1and Fig.2.Alternatively,a holder such as that shown in Fig.3may be ud to immer veral specimens at a time.However,checks must be made to assure that contact among the specimens does not result in errors.
5.5Ruler ,graduated in millimetres.
1
This test method is under the jurisdiction of ASTM Committee D20on Plastics and is the direct responsibility of Subcommittee D20.19on Film and Sheeting.Current edition approved August 10,2003.Published October 2003.Originally approved in 1968.Last previous edition approved in 1996as D 2732–96.2
Annual Book of ASTM Standards ,V ol 08.01.3
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Annual Book of ASTM Standards ,V ol 14.03.4
Available from American National Standards Institute (ANSI),25W.43rd St.,4th Floor,New York,NY 10036.
1
*A Summary of Changes ction appears at the end of this standard.
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6.Test Specimen
6.1The test specimen shall consist of 100by 100-mm samples.
6.2A minimum of two specimens is necessary for each test temperature.
7.Conditioning
7.1Conditioning —Condition the test specimens at 2362°C [73.463.6°F]and 5065%relative humidity for not less than 40h prior to test in accordance with Procedure A of Practice D 618,for tho tests where conditioning is required.In cas of disagreement,the tolerances shall be 61°C [61.8°F]and 62%relative humidity.
7.2Test Conditions —Set the liquid bath temperature to within 60.5°C of the desired temperature and allow to stabi-lize.
8.Procedure
8.1Stamp and cut out the stamped ction of film.A small border of film may be left around the stamped area.
8.1.1As an alternative method,the specimens may be cut with a die or with the aid of a template.An edge of the die may be notched to designate film direction.
8.2Place the specimen in a free shrink holder such that it is free from contact with the edges of the holder.The holder should restrain the specimen from floating in the bath medium while allowing free circulation of the bath medium around the specimen.Multiple specimens can be tested but care should be exercid to prevent restraint between the specimens.
8.3Obrve and record the temperature of the bath before immersion of each specimen.
可爱到爆炸的句子8.4Immer the specimen in the bath for 10s or a time determined to be sufficient for the material to come to thermal equilibrium and undergo maximum shrinkage.Do not hold the specimen over the bath prior to immersion,as it may result in premature shrinkage or annealing,which may introduce an error.
N OTE 3—Immersion for 10s has been determined to be generally adequate for most thermoplastics of up to 0.05mm [0.002in.]thickness;however,for new or thicker materials,a different time of immersion
may
NOTE:
1.(A )Cut hardware cloth 61⁄8by 61⁄8.(B )Form a pocket in center of cloth.(C )Weld cloth to frame as shown.
2.Two required for asmbly.
FIG.1Construction of Top and Bottom Grid Retainers of Specimen
Holder
be required to ensure maximum shrinkage at the temperature of interest.
8.5Remove the specimen from the bath and quickly im-mer in a liquid medium at room temperature preferably miscible with the bath medium.
8.6After 5s remove the specimen from the cooling medium and measure and record the linear dimensions of the specimen in both the machine (longitudinal)and transver
directions.
N OTE 1—Weld one wire frame to the inside of both arms of the tongs as shown.
FIG.2Asmbly of Specimen
Holder
FIG.3Trough and Wire
Basket
N OTE 4—Caution:Avoid stretching the specimen.
9.Calculation
9.1Determine the percent free shrinkage for each direction as follows:
Unrestrained linear shrinkage,%5@~L 02L f !/L 0#3100
(1)
where:
L 0=initial length of side (100mm),and L f =length of side after shrinking.
N OTE 5—If the material elongates,a negative number will result.N OTE 6—Since the original dimen
sion is exactly 100mm,the shrinkage may be read directly from the rule by placing the 100-mm mark on one end of the line and reading millimetres opposite the other end of the line as the percent shrinkage.
9.2Sample Calculations :
Initial length,L 05100mm (2)Length after shrinkage,L f 575mm
(3)
Unrestrained linear shrinkage,%5@~100275!/100#3100525
(4)10.Report
10.1The report shall include the following:
10.1.1Average percent linear free shrinkage in both direc-tions,machine (longitudinal)and transver,10.1.2Bath temperature,
10.1.3Complete sample identification,and 10.1.4Number of specimens tested.
11.Precision and Bias
11.1Precision —Round-robin tests between five locations have shown good agreement by this procedure with reproduc-ibility as shown in Fig.4and Fig.5;however,the round-robin data is unavailable to calculate the parameters for a formal precision and bias statement.
11.2Bias —There are no recognized standards by which to estimate the bias of this test method.
12.Keywords
12.1free shrink;plastics;sheeting;unrestrained linear
shrinkage
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FIG.4Round-Robin Data for Machine-Direction Shrinkage of Biaxially-Oriented Polysulfone
Sheeting
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SUMMARY OF CHANGES
This ction identifies the location of lected changes to this test method.For the convenience of the ur,Committee D20has highlighted tho changes that may impact the u of this test method.This ction may also include descriptions of the changes or reasons for the changes,or both.
D 2732-03:
(1)Revid Note 1.
(2)Added Terminology D 883.
(3)Deleted Practice D 1898.车牌怎么上
(4)Added ISO 11501to Referenced Documents ction.(5)Deleted paragraph 6.3.
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FIG.5Round Robin Data for Transver-Direction Shrinkage of Biaxially-Oriented Polysulfone
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Sheeting
