1、Designation: D4441 04 (Reapproved 2010)D4441 15Standard Specification forAqueous Dispersions of Polytetrafluoroethylene1This standard is issued under the fixed designation D4441; 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. Scope Scope*1.1 This specification covers aqueous dispersions of polytetrafluoroethylene (PTFE) resins. These resins ar
3、e homopolymers oftetrafluoroethylene, or in some cases modified homopolymers containing not more than 1 % by weight of other fluoromonomers.1.1.1 The dispersion is usually stabilized by one or more surfactants. Other non-PTFE materials may be present in total at 5 %or less by weight for special purp
4、oses.1.1.2 This specification is for virgin material only and does not address recycled material as it is not appropriate for dispersions.1.2 This specification is used to determine if a shipment, lot, or container of PTFE dispersion is suitable for its intended use.It covers only aqueous dispersion
5、s of polytetrafluoroethylene. It does not cover PTFE copolymers or filled dispersions. Thisspecification includes test methods for both aqueous dispersion and the PTFE in the dispersion.NOTE 1Uses for the PTFE dispersion covered by this specification include, but are not limited to, casting of their
6、 films, impregnation of mechanicalpackings and other materials, surface coatings on various substrates, combined impregnation and coating of fibrous materials, and co-coagulation withother materials for subsequent processing into films, sheets, rods, and tubes.NOTE 2Information in this specification
7、 is technically equivalent to related information in ISO 12086-1 and ISO 12086-2.1.3 The values stated in SI units as detailed in IEEE/ASTM SI-10 are to be regarded as standard. The values given inparentheses are for information only.1.4 The following precautionary caveat pertains only to the test m
8、ethod portions of this specification. This standard does notpurport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard toestablish appropriate safety and health practices and determine the applicability of regulatory limitati
9、ons prior to use. Specificprecautionary information is given in Notes 5 and 6.2. Referenced Documents2.1 ASTM Standards:2D883 Terminology Relating to PlasticsD3892 Practice for Packaging/Packing of PlasticsD4464 Test Method for Particle Size Distribution of Catalytic Materials by Laser Light Scatter
10、ingD4591 Test Method for Determining Temperatures and Heats of Transitions of Fluoropolymers by Differential ScanningCalorimetryD4894 Specification for Polytetrafluoroethylene (PTFE) Granular Molding and Ram Extrusion Materials3D4895 Specification for Polytetrafluoroethylene (PTFE) Resin Produced Fr
11、om Dispersion3E70 Test Method for pH of Aqueous Solutions With the Glass ElectrodeIEEE/ASTM SI-10 Use of the International System of Units (SI): The Modern Metric System2.2 ISO Standards:4ISO 12086-1 Plastics Fluoropolymer Dispersions and Molding and Extrusion MaterialsPart 1: Designation and Specif
12、icationISO 12086-2 Plastics Fluoropolymer Dispersions and Molding and Extrusion MaterialsPart 2: Preparation of Test Specimensand Determination of Properties1 This specification is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.15 on The
13、rmoplasticMaterials(Section D20.15.12).Current edition approved Jan. 1, 2010May 1, 2015. Published January 2010June 2015. Originally approved in 1984. Last previous edition approved in 20042010 asD4441 - 04.D4441 - 04(2010). DOI: 10.1520/D4441-04R10.10.1520/D4441-15.2 For referencedASTM standards, v
14、isit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Specifications for other forms of polytetrafluoroethylene may be found in Specifications D48
15、94 and D4895.4 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http:/www.ansi.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previou
16、s version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Change
17、s section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13. Terminology3.1 Definitions:3.1.1 GeneralThe terminology given in Terminology D883 is applicable to this specification.3.2 Definitions of T
18、erms Specific to This Standard:3.2.1 dispersion, na two phase system of which one phase consists of finely divided particles distributed throughout a bulksubstance, the particles being the disperse phase and the bulk phase being the continuous phase.3.2.2 dispersion particle sizea particle size meas
19、ured in the presence of added surfactant.3.2.3 raw dispersion particle sizea particle size measured in the absence of added surfactant (except for the small amount usedin polymerization).3.2.4 lot, none production run or a uniform blend of two or more production runs.3.2.5 sintering, nas it applies
20、to PTFE, a thermal treatment during which the PTFE is melted and recrystallized by coolingwith coalescence occurring during the treatment.3.2.6 standard specific gravity (SSG), nthe specific gravity of a specimen of PTFE material molded as described in thisspecification and sintered using the approp
21、riate sintering schedule given in this specification.4. Classification4.1 This specification covers four types of virgin PTFE dispersions classified into those equal to or below 40 % PTFE and thoseabove 40 % PTFE, and those containing added surfactant and those not containing added surfactant. The d
22、ispersions are classifiedinto 13 grades depending on the level of added surfactant. Three classes of Surfactant Tolerance Level are provided to furtherdifferentiate the dispersion variability needed.NOTE 3The surfactant content is weight percent and is based on the solid, dry PTFE.4.2 A line callout
23、 system is used to specify materials in this specification. The system uses predefined cells to refer to specificaspects of this specification, illustrated as follows:SpecificationStandard Number Block: Type Grade Class Special NotesExample: SpecificationD4441 - XX,II 3 AFor this example, the line c
24、allout would be Specification D4441 XX, II3A and would specify a virgin PTFE dispersion thathas all the properties listed for that type, grade, and class in the appropriate specified tables. A comma is used as the separatorbetween the standard number and the type and class. Separators are not needed
25、 between the type, grade, and class.5 Provision forspecial notes is included so that other information can be provided when required.5 See the ASTM Form and Style Manual available from ASTM Headquarters.TABLE 1 PTFE Level, Surfactant Level, and Tolerance LevelRequirementsType % PTFE Grade Nominal %A
26、ddedSurfactantClass SurfactantToleranceLevelI #40 0 040 2 $240 with 0 %addedsurfactant9 $91010 $101111 $111212 $1213D4441 1525. Ordering Information5.1 Orders for material under this specification shall contain the following information:5.1.1 Quantity, Grade, Class,5.1.2 Name of material (Aqueous di
27、spersion of PTFE),5.1.3 ASTM designation and year,5.1.4 Type,5.1.5 Additions to the specification and supplementary requirements, if required.6. Other Requirements6.1 SignificanceIn addition to tests on the dispersion and the polymer, the following requirements apply:6.2 The dispersion shall be free
28、 of contamination, dirt, mold, etc. It shall be of uniform composition. The expected level ofcoagulated polymer shall be specified.7. Sampling7.1 PTFE solids in the dispersion tend to settle upon standing. Therefore, the dispersion shall be homogenized by gentle mixingbefore sampling. Gentle mixing
29、includes rolling a drum for 5 min at 3 to 4 rpm, by stirring with a smooth rod for 3- to 4-min,or by other types of gentle agitation. (WarningVigorous agitation will coagulate the dispersion.)7.2 After blending, take the sample by removing an aliquot. A suitable method is by inserting a clean, smoot
30、h, dry glass tube,open at both ends, until it reaches the bottom of the container. An internal diameter of 6 or 7 mm (0.25 in.) is suitable. Smooththe ends of the tube to prevent injury. Close the upper end of the tube, remove the tube from the container, and transfer the contentsto a clean dry glas
31、s jar. Repeat until the desired sample size is reached.7.3 When samples are drawn from several containers, the individual samples shall be combined and thoroughly mixed by gentlestirring when the samples are combined and again before the combined sample is tested.8. Test Methods for Dispersions8.1 S
32、copeThe specification contains test methods to define characteristics of the polymer and of the dispersion of the polymer.This section defines tests on the dispersion of the polymer.8.2 pH ValueThe test method shall be in accordance with Test Method E70. Some buyers or sellers attach importance to t
33、hepH of the PTFE dispersion. The pH value is not specified in this ASTM Standard.NOTE 4If the PTFE dispersion coats the electrode, clean the electrode thoroughly using a soft cloth wet with either toluene or concentratedsurfactant.6NOTE 5Warning: Toluene is hazardous. Consult appropriate safety info
34、rmation on the material Safety Data Sheet before using.8.3 Solid Content and Surfactant Content by Gravimetric Weight Loss:8.3.1 SignificanceDetermine the percent PTFE solids and the percent surfactant by successive evaporations of water andsurfactant. The percent surfactant is based on the weight o
35、f the PTFE. All percentages are based on weight.8.3.2 ApparatusAn aluminum weighing dish, an oven capable of reaching 120 6 5C (248 6 9F),105 6 5C (221 6 9F),and an oven capable of reaching 380 6 10C (716 6 18F). Balance capable of weighing down to 0.0001 g.8.3.3 ProcedureWeigh the aluminum weighing
36、 dish to 0.0001 g (WA). Add 10 g of PTFE dispersion and weigh immediatelyto 0.0001 g (WB). Dry the sample for 2 h at 120 6 5C. 105 6 5C (221 6 9F). Weigh the sample to 0.0001 g (WC) after coolingto room temperature in a desiccator. After weighing, evaporate the surfactant by placing the sample in an
37、 oven at 380 6 5C(716 6 9F) for 35 6 1 min. Allow the sample to cool in a desiccator to room temperature and weigh to 0.0001 g (WD).8.3.4 CalculationsFor surfactants that are completely volatile use the following:PTFE,%5 WD 2 WA!WB 2 WA!3100surfactant,%5 WC 2 WD!WD 2 WA!31008.3.4.1 For surfactants t
38、hat are not completely volatile use the following:PTFE,%5 WC 2 WA! 2 WC 2 WD! 311k!#WB 2 WA!31006 Examples of a suitable surfactant are “Glim” detergent, B. J. Babbitt, Inc., “Joy” detergent, Proctor and Gamble, Inc., and “Triton” X-100, Rohm and Haas Co.D4441 153surfactant,%5 WC 2 WD! 311k!WC 2 WA!
39、 2 WC 2 WD! 311k!#3100where:k = weight of nonvolatile portion of the surfactant/weight of volatile portion of the surfactant.NOTE 6Upon request, the supplier shall inform the user whether the surfactant can be completely removed by the procedures of this specification;and if not, shall define the su
40、rfactant or the volatile and nonvolatile portions of the surfactant.8.3.5 Precision and BiasNo information can be presented on the precision and bias because of insufficient participation in theinvestigation.8.3.6 The results of these tests on solids contents and surfactant shall conform to one of t
41、he types of dispersion listed in 4.1.8.4 Solids Content by Hydrometer:8.4.1 SignificanceAn approximate solids content in a dispersion is commonly determined from the specific gravity of thedispersion. The hydrometer reading is a function of the solids content, the surfactant content, and other param
42、eters of thedispersion. Therefore, any single conversion table has inherent error and cannot be universally applicable. A table should beobtained from the supplier.8.4.2 ApparatusA hydrometer or set of hydrometers capable of measuring specific gravity from 1.000 to 1.500. Accuracy ofthe hydrometer s
43、hall be 60.001. A graduated cylinder large enough to hold the hydrometer.8.4.3 ProcedureFill the graduated cylinder with PTFE dispersion to float the hydrometer. Place the hydrometer into thecylinder. Add dispersion until the cylinder is full and the meniscus is slightly convex. Read the hydrometer
44、at the top of thedispersion. The reading shall be accurate to 0.001. Translate the hydrometer reading to solids content using the table.8.4.4 Precision and BiasNo information can be presented on the precision and bias because of insufficient participation in theinvestigation.NOTE 7Some of the additi
45、ves permitted in accordance with 1.1.1 may increase the viscosity of the dispersion so much that it is unlikely that thehydrometer procedure will be used to determine the density in a reliable manner.8.5 Test for Coagulated Polymer:8.5.1 SignificancePolymer that has coagulated may not be useful to t
46、he purchaser. This test will determine the percent ofcoagulated polymer.8.5.2 ApparatusA tared beaker to hold 1000 6 1 g of dispersion; a filter screen, 80 mesh; a funnel, an oven capable ofoperating at 120 6 5C (248 6 9F)105 6 5C (221 6 9F) desiccator; balance capable of 1 mg.8.5.3 MaterialsDistill
47、ed water PTFE dispersion.8.5.4 ProcedureWeigh a 1000 6 1 g of dispersion (WD) into the tared beaker. Weigh the screen to 1.0 mg and record theweight (WS). Secure the screen to the funnel and filter the dispersion through the screen. Rinse the beaker with 25 mL of distilledwater and use this rinse wa
48、ter to wash the coagulum on the screen. Gently wash the coagulated polymer on the screen with 25 mLof distilled water from a wash bottle. Carefully remove the screen from the funnel and dry at 120 6 5C (248 6 9F)105 6 5C(221 6 9F) for 2 h. Weigh the screen and coagulum to 1 mg after allowing it to c
49、ool to room temperature in a desiccator. Recordthe weight as WC.8.5.5 CalculationCalculate the coagulum content as follows:coagulum content,%5 WC 2 WS!WD 3PTFEcontent, %!3100where:WD = mass of dispersion sample, g,WS = mass of screen, g,WC = mass of screen and coagulated polymer, g, and PTFE content, %, = PTFE, % in the dispersion as determined in 8.3. Itis to be expressed as a decimal fraction.9. Methods for Tests on PTFE in the Dispersion9.1 ScopeThe specification contains test methods to define char
