1、Designation: D 3596 09Standard Practice forDetermination of Gels (Fisheyes) In General-PurposePoly(Vinyl Chloride) (PVC) Resins1This standard is issued under the fixed designation D 3596; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revis
2、ion, 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. Scope*1.1 This practice provides a quantitative measure of the gelsremaining in a flexible vinyl compound proc
3、essed fromgeneral-purpose poly(vinyl chloride) (PVC) resins under aprescribed set of working conditions.1.2 The values stated in SI units are to be regarded as thestandard. The values in parentheses are for information only.1.3 This standard does not purport to address all of thesafety problems, if
4、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 to use.NOTE 1There is no known ISO equivalent to this standard.2. Referenced Documents2.1 ASTM Sta
5、ndards:2D 883 Terminology Relating to PlasticsD 1600 Terminology for Abbreviated Terms Relating toPlastics3. Terminology3.1 GeneralDefinitions are in accordance with Terminol-ogy D 883 and abbreviations with Terminology D 1600, unlessotherwise indicated.4. Summary of Practice4.1 A sample of PVC resi
6、n is mixed with calcium/zincstabilizer, stearic acid, carbon black, and a plasticizer in alaboratory mixer. The dry blend is milled on a two-rolllaboratory mill.4.2 The milled sheet is press-polished and the gels countedusing a bottom-lighted viewing box and a magnifying com-parator.5. Significance
7、and Use5.1 The gel (fisheye) in PVC resins is generally recognizedas a hard particle of resin which will not fuse when the plasticmass is subjected to set conditions of hot processing. Thenumber of unfused particles present is related to the conditionsused. The presence of an excess of such particle
8、s is detrimentalto many applications.6. Apparatus6.1 Laboratory Mixer, with stainless steel mixing bowl.6.2 Two-Roll Mill, 152.4 by 304.8 mm (6 by 12 in.), 263.5mm (10.5 in.) between guides, differential speed ratio 1.40 60.04, fast roll speed 34 6 2 rpm, with an adjustable tempera-ture range of 120
9、205C (250400F).NOTE 2If the mill available does not meet these criteria, the specifi-cations of the mill used should be included in the report.6.3 Surface Pyrometer6.4 Balance, 0.1-g sensitivity.6.5 Hydraulic Press having platens at least 203 by 203 mm(8 by 8 in.), rated at a minimum of 140 MPa (20
10、000 psi) rampressure on a 100-mm (4-in.) ram, which may be heated to 1636 3C (325 6 5F) on the pressing surfaces and equipped withcooling water.6.6 Timer, capable of being read in seconds.6.7 Cotton Gloves.6.8 Mill Knife.6.9 Plates or Mold, two 203 by 203-mm (8 by 8-in.)chrome-plated ferro plates, o
11、r a chrome-plated mold with a 152by 152 by 6.4-mm (6 by 6 by 0.25-in.) cavity.6.10 Backing Plates, two 203 by 203 by 6.4 mm (8 by 8 by0.250 in.).6.11 Brass Shims, four, 0.51 by 13 by 203 mm (0.020 by 0.5by 8.0 in.).6.12 Magnifying Comparator, equipped with a transparentreticule (scale) showing circl
12、es from 0.03 to 1.27 mm (0.001 to0.050 in.) in diameter.6.13 Bottom-Lighted Viewing Box.1This practice is under the jurisdiction ofASTM Committee D20 on Plastics andis the direct responsibility of Subcommittee D20.15 on Thermoplastic Materials.Current edition approved Feb. 1, 2009. Published Februar
13、y 2009. Originallyapproved in 1977. Last previous edition approved in 2001 as D 3596 92(2001).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document
14、 Summary page onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7. Materials7.1 PVC Resin7.2 Plasticizer7.2.1 Plasticizer TypeThe plasticizer selected
15、 shall repre-sent the plasticizer type commonly used with the resin beingtested. Less solvating plasticizers will yield a higher gel count.7.2.2 Plasticizer LevelThe plasticizer usage level shallyield a test compound with approximately the same shorehardness as the compound that will be based on the
16、 resin beingtested.7.3 Stearic Acid7.4 Liquid Calcium/Zinc Stabilizer7.5 Carbon Black8. Procedure8.1 Weigh 200 g of the sample resin, 4.0 g liquid calcium/zinc stabilizer, 0.5 g stearic acid, 0.6g carbon black, andplasticizer into the stainless steel mixing bowl. Blend theingredients in the laborato
17、ry mixer at 23 6 2C (73 6 3.6F)for 3 min.NOTE 3Other mixers capable of yielding a uniform dispersion can beemployed.8.2 Set the mill temperature so the dry blend fuses andbands on the front roll of the mill within 4590 seconds andcheck to determine that the mill rolls and guides are clean.8.2.1 Set
18、the mill rolls to produce a milled sheet with athickness of 0.64 6 0.05 mm (0.025 6 0.002 in.).NOTE 4If the mill cannot be set to give the specified thickness set therolls as closely together as possible and report the sheet thickness with thedata. If the mill opening between the rolls is in excess
19、of 0.64 mm (0.025in.) the reduced working of the stock can result in an apparent higher gel(fisheye) count for the sample.8.2.2 Place a clean sheet of paper beneath the rolls. With themill running, transfer 150 g of the dry blend (produced in 8.1)to the mill and immediately start the timer. Work the
20、 stockcontinuously by making a cut from one side to within about 25mm (1 in.) of the opposite side. Use the mill knife to peel offas much of the stock as possible without completely removingit, fold the strip over and feed it back into the mill. During thefirst 0.5 min, add the initial droppings bac
21、k into the stock;discard subsequent droppings. Cut and fold the stock after 1.5min and every 0.5 min thereafter. Mill for a total of 5 6 0.1min from start of test.NOTE 5Due to differences between mills, it will be necessary toadjust the amount of dry blend used to that weight which will band on ther
22、oll and produce a 9.5-mm (0.375-in.) diameter (pencil size) rolling bank.Use a clean-up batch to determine the correct amount. Report the weightof dry blend used.8.3 Cut a 152 by 152-mm (6 by 6-in.) section from themilled stock.8.3.1 Place the section cut from the milled sheet between thetwo chrome-
23、plated ferro plates, chrome side to the specimen,then put the chrome ferro plates and the specimen between thebacking plates and insert in a press at 163 6 3C (325 6 5F).Preheat for 0.5 min with the press closed at zero pressure. Achrome-plated mold can be used instead of the plates.8.3.2 After preh
24、eating, apply ram pressure for 2 min. Useenough pressure to produce a sheet thickness of 0.5 6 0.03 mm(0.020 6 0.001 in.). At the end of the 2 min, turn the heat offand the cooling water on. Allow the press to cool to roomtemperature under pressure. Release the pressure; remove theplates from the pr
25、ess and carefully remove the pressed sheetspecimen.8.4 Place the 152 by 152-mm (6 by 6-in.) press polishedsheet on the view box and count the gel particles using themagnifying comparator. Classify the gels (clear unpigmentedareas) as follows:8.4.1 Gel Size A, gels greater than or equal to 0.5-mm(0.0
26、20-in.) diameter.8.4.2 Gel Size B, gels greater than or equal to 0.4-mm(0.015-in.) diameter.8.4.3 Gel Size C, gels greater than or equal to 0.3-mm(0.01-in.) diameter and less than 0.4-mm (0.015-in.) diameter.9. Report9.1 A Gels, count/232 cm2(count/36 in.2). B Gels, count/232cm2(count/36 in.2). C Ge
27、ls, count/232 cm2(count/36 in.2),9.2 Mill specifications if different from the specificationslisted in the procedure,9.3 Thickness of milled sheet if other than specified in 8.2.1,9.4 Amount of dry blend used if other than 150 g, and9.5 Thickness of pressed sheet if other than specified in8.3.2.10.
28、Precision and Bias310.1 Interlaboratory evaluation by five laboratories yieldedseven sets of determinations. Analysis indicated the followingvalues of precision of count at a probability level ofP = 0.95.10.1.1 Gel Size A, 61.10.1.2 Gel Size B, 65.10.1.3 Gel Size C, 612.10.2 Since no absolute method
29、 of gel count is available, nostatement of bias can be prepared.11. Keywords11.1 fisheyes; gels; poly(vinyl chloride) resin3Supporting data are available from ASTM Headquarters. Request RR:D20-1106.D3596092SUMMARY OF CHANGESCommittee D20 has identified the location of selected changes to this standa
30、rd since the last issue(D 3596 - 92(2001) that may impact the use of this standard. (February 1, 2009)(1) Updated ISO equivalency statement, in accordance withD4968, in Note 1.(2) Deleted ASTM D 1249 reference in 2.1.(3) Revised 4.1, 6.2, 6.3, 7.2, 7.3, 7.4, 8.1, 8.2, and 8.2.2.(4) Deleted old 8.2.2
31、.(5) Removed old Footnotes 3, 4, 5, 6, and 7.(6) Removed dispersion reference from 7.5 and 8.1.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determina
32、tion 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 not revised, either reapproved or with
33、drawn. 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 you may attend. If you feel that you
34、r 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,United 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).D3596093
