1、Designation: D3596 09D3596 13Standard Practice forDetermination of Gels (Fisheyes) In General-PurposePoly(Vinyl Chloride) (PVC) Resins1This standard is issued under the fixed designation D3596; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、 revision, 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 gels remaining in a flexible vinyl compou
3、nd processed fromgeneral-purpose poly(vinyl chloride) (PVC) resins under a prescribed set of working conditions.1.2 The values stated in SI units are to be regarded as the standard. The values in parentheses are for information only.1.3 This standard does not purport to address all of the safety pro
4、blems, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.NOTE 1There is no known ISO equivalent to this standard.2. Referenced Documents2.1 A
5、STM Standards:2D883 Terminology Relating to PlasticsD1600 Terminology for Abbreviated Terms Relating to Plastics3. Terminology3.1 GeneralDefinitions are in accordance with Terminology D883 and abbreviations with Terminology D1600, unlessotherwise indicated.4. Summary of Practice4.1 A sample of PVC r
6、esin is mixed with calcium/zinc stabilizer, stearic acid, carbon black, and a plasticizer in a laboratorymixer. The dry blend is milled on a two-roll laboratory mill.4.2 The milled sheet is press-polished and the gels counted using a bottom-lighted viewing box and a magnifying comparator.5. Signific
7、ance and Use5.1 The gel (fisheye) in PVC resins is generally recognized as a hard particle of resin which will not fuse when the plastic massis subjected to set conditions of hot processing. The number of unfused particles present is related to the conditions used. Thepresence of an excess of such p
8、articles is detrimental to 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.), 263.5 mm (10.5 in.) between guides, differential speed ratio 1.40 6 0.04,fast roll speed 34 6 2 rpm, with an adjustable temperature range
9、 of 120205C (250400F).NOTE 2If the mill available does not meet these criteria, the specifications of the mill used should be included in the report.6.3 Surface Pyrometer6.4 Balance, 0.1-g sensitivity.1 This practice is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct respo
10、nsibility of Subcommittee D20.15 on Thermoplastic Materials.Current edition approved Feb. 1, 2009Nov. 1, 2013. Published February 2009November 2013. Originally approved in 1977. Last previous edition approved in 20012009as D3596 92D3596 09.(2001). DOI: 10.1520/D3596-09.10.1520/D3596-13.2 For referen
11、cedASTM standards, visit 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.This document is not an ASTM standard and is intended only to provide the
12、user of an ASTM standard an indication of what changes have been made to the previous 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
13、 as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16.5 Hydraulic Press having platens at least 203 by 203 mm
14、 (8 by 8 in.), rated at a minimum of 140 MPa (20 000 psi) rampressure on a 100-mm (4-in.) ram, which may be heated has the capacity for heating to 163 6 3C (325 6 5F) on the pressingsurfaces and equipped with cooling water.6.6 Timer, capable of being read in seconds.6.7 Cotton Gloves.6.8 Mill Knife.
15、6.9 Plates or Mold, two 203 by 203-mm (8 by 8-in.) chrome-plated ferro plates, or a chrome-plated mold with a 152 by 152by 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 by 0.250 in.).6.11 Brass Shims, four, 0.51 by 13 by 203 mm (0.020 by 0.5 by 8.0 in.).6.1
16、2 Magnifying Comparator, Comparator (optional), equipped with a transparent reticule (scale) showing circles from 0.03 to1.27 mm (0.001 to 0.050 in.) in diameter.6.13 Bottom-Lighted Viewing Box.7. Materials7.1 PVC Resin7.2 Plasticizer7.2.1 Plasticizer TypeThe plasticizer selected shall represent the
17、 plasticizer type commonly used with the resin being tested.Less solvating plasticizers will yield a higher gel count.7.2.2 Plasticizer LevelThe plasticizer usage level shall yield a test compound with approximately the same shore hardness asthe compound that will be based on the resin being tested.
18、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, and plasticizerinto the stainless steel mixing bowl. Blend the ingredients in the laboratory mixer at 23 6 2
19、C (73 6 3.6F) for 3 min.NOTE 3Other mixers capable of yielding a uniform dispersion can be employed.8.2 Set the mill temperature so the dry blend fuses and bands on the front roll of the mill within 4590 seconds and check todetermine that the mill rolls and guides are clean.8.2.1 Set the mill rolls
20、to produce a milled sheet with a thickness 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 the rolls as closely together as possible and report the sheet thickness with thedata. If the mill opening between the rolls is in excess of 0.64 mm (0
21、.025 in.) 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 the mill running, transfer 150 g of the dry blend (produced in 8.1) tothe mill and immediately start the timer. Work the stock cont
22、inuously by making a cut from one side to within about 25 mm (1in.) of the opposite side. Use the mill knife to peel off as much of the stock as possible without completely removing it, fold thestrip over and feed it back into the mill. During the first 0.5 min, add the initial droppings back into t
23、he stock; discard subsequentdroppings. Cut and fold the stock after 1.5 min and every 0.5 min thereafter. Mill for a total of 5 6 0.1 min from start of test.NOTE 5Due to differences between mills, it will be necessary to adjust the amount of dry blend used to that weight which will band on the roll
24、andproduce a 9.5-mm (0.375-in.) diameter (pencil size) rolling bank. Use a clean-up batch to determine the correct amount. Report the weight of dry blendused.8.3 Cut a 152 by 152-mm (6 by 6-in.) section from the milled stock.8.3.1 Place the section cut from the milled sheet between the two chrome-pl
25、ated ferro plates, chrome side to the specimen, thenput the chrome ferro plates and the specimen between the backing plates and insert in a press at 163 6 3C (325 6 5F). Preheatfor 0.5 min with the press closed at zero pressure. A chrome-plated mold can be used instead of the plates.8.3.2 After preh
26、eating, apply ram pressure for 2 min. Use enough pressure to produce a sheet thickness of 0.560.03 mm (0.0206 0.001 in.).At the end of the 2 min, turn the heat off and the cooling water on.Allow the press to cool to room temperature underpressure. Release the pressure; remove the plates from the pre
27、ss and carefully remove the pressed sheet specimen.8.4 Place the 152 by 152-mm (6 by 6-in.) press polished sheet on the view box and count the gel particles using the visuallyor by the use of a magnifying comparator. Classify the gels (clear unpigmented areas) as follows:8.4.1 Gel Size A, gels great
28、er than or equal to 0.5-mm (0.020-in.) diameter.D3596 1328.4.2 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)
29、. B Gels, count/232 cm2 (count/36 in.2). C Gels, count/232 cm2 (count/36 in.2),9.2 Mill specifications if different from the specifications listed 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 pre
30、ssed sheet if other than specified in 8.3.2.9.6 Measurement method (visual or comparator).10. Precision and Bias310.1 Interlaboratory evaluation by five laboratories yielded seven sets of determinations.Analysis indicated the following valuesof precision of count at a probability level ofP = 0.95.10
31、.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 of gel count is available, no statement of bias can be prepared.11. Keywords11.1 fisheyes; gels; poly(vinyl chloride) resinSUMMARY OF CHANGESCommittee D20 has identified the location of selected changes to
32、 this standard since the last issue(D3596 - 92D3596 - 09(2001) that may impact the use of this standard. (February(November 1, 2009)2013)(1) Updated ISO equivalency statement, inRemoved permissive language from 6.5 accordance with D4968, in Note 1.(2) Deleted ASTMReworded 6.12 D1249 reference in and
33、 2.18.4.(3) RevisedAdded 4.19.6,: 6.2,noted 6.3,use 7.2,of 7.3,magnifying 7.4,comparator 8.1,or 8.2, andvisual in 8.2.2.report.(4) Deleted old 8.2.2.(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 valid
34、ity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subje
35、ct to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn.Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarte
36、rs. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your 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
37、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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).3 Supporting data are available from ASTM Headquarters. Request RR:D20-1106.D3596 133
