A number in parentheses indicates the year of last reapproval. This standard has been approved for use by agencies of the U. Department of Defense. It also specifies the mixing equipment, generalmixing procedures, vulcanization equipment and procedures.

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You are on page 1of 6 Search inside document Designation: D 89 Reapproved Standard Practice for RubberMaterials, Equipment, and Procedures for Mixing Standard Compounds and Preparing Standard Vulcanized Sheets1 This standard is issued under the fixed designation D ; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision.

A number in parentheses indicates the year of last reapproval. A superscript epsilon e indicates an editorial change since the last revision or reapproval. This standard has been approved for use by agencies of the Department of Defense.

Significance and Use listed in succeeding methods and contains procedures for weighing. It also specifies the mixing equipment, general 3. The values given in parentheses are for information son of different materials.

Standard Materials 1. It is the 4. However, in case of dispute, the following actual standard materials from 2. A substitute material Procedures. Current edition approved Mar. Published May IRM is available from Akron published as D Last previous edition D Chemical Co. Other ratios may be used, but modifications in mixing testing ASTM Oil Type procedure may be required to obtain equivalent results.

The use of other than a standard mill shall be recorded with the reported 5. Weighing of Materials data. Roll clearance shall be determined by means of density of the rubber compound. The lead strips shall be multiplied by the density of the rubber compound. All other materials shall be weighed with a The rolls shall be at the accuracy or less for mill and internal mixer compounds and temperature specified for mixing. After the lead strips have with Tolerance on a roll clearance 5.

Such blend with approximately cm3 displacement volume, resulting in may be made in a mortar and pestle, by mixing for 10 min in 6 cm3 loading capacity. The slow rotor speed shall be a biconical blender with intensifier bar turning, or by mixing in 8. The a blender9 for five 3-s periods and scraping the inside of the rotor wing tip to side clearance shall be 2. The mixer shall be equipped with mix. Caution: If mixed longer than 3 s, the stearic acid may a thermocouple for measuring and recording batch mixing melt and prevent good dispersion.

The thermocouple shall be installed through the 5. The sides mm 0. Store the conditioned carbon shall be hinged to swing open, made of cast stainless steel and black in a closed moisture-proof container until cool and then jacketed for controlling temperature by means of a circulating use for weighing and mixing.

The end frames shall be of ductile iron that has a 0. Equipment for Mixing the working surfaces. Rotors are of stainless steel, nitrided, 6. The mill shall be NOTE 2If internal mixers of other sizes are used, adjustments of batch equipped with retaining guides, with a distance between the masses and rotor speeds or mixing cycles will be required to obtain guides at the nip of to mm 10 to 11 in.

NOTE 1If mills of other sizes are used, adjustments to batch masses 6. The recommended loading 8 Defined by Classification D The fast or driving rotor left shall turn at tion in Classification D and more specifically, to the values listed below, can be obtained from Sun Refining and Marketing Co. The mixing 9 A Waring Blender has been used in this practice. Results cannot be guaranteed chamber shall be closed during the mixing cycle by means of using another brand. The head and the backplate shall be maintained 2 at the required temperature either electrically or by means of a the second-stage mix.

The batch should then be discharged at equivalent results. If the second-stage mix is 6. The batch size may be reduced to better accommo- essential for the mixing operation. If used, it must be calibrated date the mill and to result in better dispersion of compounding occasionally and after each overhaul of the miniature internal materials.

General Mixing Procedures 0. The before mixing. It should be 7. Make successive 34 cuts from fied for the rubber. Add all other dry materials slowly and evenly in pre- 7. Oil, if required, may be added alternately with compound viscosity or tension specimen, or both are required, carbon black. Carefully collect materials falling through the pass the batch endwise through the mill six times with an nip from the tray and return to the mix.

Fold it lengthwise 7. The roll opening should be such that 7. Preparation of Standard Vulcanized Sheets 0. For maximum precision, the internal mixer or on the standard mill. Mark the direction of the milling on each 7. The Compound 6 by 6 in. If chamber-type platens are 1. Reduce conduction of heat 1.

Platens should be suitably shielded from drafts. The 1. With either type of platen, the tempera- 1. The maximum 8. Between adjacent platens the tem- and below the sheet in the mold to prevent contamination with perature difference between corresponding points on the two materials remaining in the mold from previous cures. The mass platens shall not exceed 0. The cavities to within 6. The corners of the cavities may be rounded with a period of vulcanization.

It shall have heated platens of suffi- radius not greater than 6. An alternative type of FIG. The cavities of this mold shall meet the requirements described in 8. Molds constructed of hard- ened steel are preferred, but chrome-plated mild steel and stainless steel are also acceptable. The cover of the mold shall be a flat plate at least 10 mm 0.

Instead of a separate mold and cover, the cavities may be cut directly into the platen of the press. Unless required, do not use a mold lubricant on the mold surfaces. A silicone-type lubricant or mild soap other suitable temperature measuring device inserted in one of solution has been found satisfactory. When 1F in the closed press, and hold at this temperature for at the mold is removed from the press to insert the pieces, take least 20 min before the unvulcanized pieces are inserted.

Verify precautions to prevent excessive cooling of the mold by contact the temperature of the mold by means of a thermocouple or with cool metal surfaces or by exposure to air drafts. Hold the mold under a minimum specified. As soon as the press is opened, remove the NOTE 4Quality control of rubber production may require testing vulcanized sheets from the mold and cool in water room within 1 to 6 h to provide close surveillance of the plant operation; however, slightly different results may be obtained.

Designate in the report the type of cooling used. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of 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 and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters.

Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, at the address shown below. Individual reprints single or multiple copies of this standard may be obtained by contacting ASTM at the above address or at phone , fax , or service astm.

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