ASTM D787-18

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 previous version. Because
it 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 version
of the standard as published by ASTM is to be considered the official document.
Designation: D787 − 12 D787 − 18
Standard Specification for
Ethyl Cellulose Molding and Extrusion Compounds
This standard is issued under the fixed designation D787; 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 (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope*
1.1 This specification covers requirements for plasticized ethyl cellulose thermoplastic compounds suitable for injection
molding and extrusion. It does not include special materials compounded for special applications.
1.2 The values stated in SI units are to be regarded as standard. The English values given are for information only.
1.3 The following precautionary statement pertains only to the Test Methods portion, Section 109 of this specification. This
standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user
of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the applicability
of regulatory limitations prior to use.
NOTE 1—There is no known ISO equivalent to this specification.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D256 Test Methods for Determining the Izod Pendulum Impact Resistance of Plastics
D570 Test Method for Water Absorption of Plastics
D618 Practice for Conditioning Plastics for Testing
D638 Test Method for Tensile Properties of Plastics
D648 Test Method for Deflection Temperature of Plastics Under Flexural Load in the Edgewise Position
D785 Test Method for Rockwell Hardness of Plastics and Electrical Insulating Materials
D792 Test Methods for Density and Specific Gravity (Relative Density) of Plastics by Displacement
D883 Terminology Relating to Plastics
D1505 Test Method for Density of Plastics by the Density-Gradient Technique
D3641 Practice for Injection Molding Test Specimens of Thermoplastic Molding and Extrusion Materials
D3892 Practice for Packaging/Packing of Plastics
3. Terminology
3.1 Terms in this specification are in accordance with Terminology D883.
4. Classification
4.1 This specification covers two types and eleven grades of ethyl cellulose molding and extrusion compounds as classified in
accordance with Table 1. Type I materials are general purpose and Type II are characterized by improved resistance to impact,
especially at low temperatures. The grades are classified in accordance with their physical properties as specified in Table 1.
4.1.1 A typical call out of material covered by this specification would contain the number of this specification and the required
type and grade chosen from Table 1, for example, D787 Type 1, Grade 1.
This specification is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.15 on Thermoplastic Materials.
Current edition approved Aug. 1, 2012April 1, 2018. Published August 2012April 2018. Originally approved in 1944. Last previous edition approved in 20092012 as
D787 – 09.12. DOI: 10.1520/D0787-12.10.1520/D0787-18.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*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
D787 − 18
TABLE 1 Detailed Requirements for Molded Test Specimens
NOTE 1—ft·lbf/in. × 53.3378660 = joules per metre. Megapascals (MPa) = newtons × 10 per metre squared.
Type I Type II
Test
Property
Grade Grade Grade Grade Grade Grade Grade Grade Grade Grade Grade
Methods
1 2 3 4 5 6 7 8 9 10 11
Specific gravity, unpigmented, max at 23/ 1.13 1.13 1.12 1.12 1.11 1.10 1.12 1.12 1.11 1.11 1.10 D792
23°C (73.4/73.4°F)
Hardness (Rockwell) R scale, min 110 110 105 105 100 95 105 80 75 75 50 D785
Tensile strength at 23°C, min:
MPa 44.8 41.4 38.1 33.0 31.0 24.2 27.6 24.1 20.7 20.0 15.9 D638
psi 6500 6000 5400 4800 4500 3800 4000 3500 3000 3300 2900
Impact strength (Izod), min
at 23°C (73.4°F):
J/m of notch 90.7 90.7 106.7 106.7 117.3 149.5 186.7 213.5 293.4 213.5 320.3 D256
ft·lbf/in. of notch 1.7 1.7 2.0 2.0 2.2 2.8 3.5 4.0 5.5 4.0 6.0
at − 40°C (−40°F):
J/m of notch 26.7 26.7 26.7 26.7 26.7 26.7 53.4 64.1 80.1 53.4 80.1 D256
ft·lbf/in. of notch 0.5 0.5 0.5 0.5 0.5 0.5 1.0 1.2 1.5 1.0 1.5
Deflection temperature, min:
at 1820-kPa (264-psi) fiber stress:
°C 82 77 71 66 60 49 66 77 71 60 49 D648
°F 180 170 160 150 140 120 150 170 160 140 120
at 455-kPa (66-psi) fiber stress:
°C 94 88 82 77 71 66 82 82 82 77 – D648
°F 200 190 180 170 160 150 180 180 180 170 –
Water absorption (24-h immersion), max % 1.7 1.5 1.4 1.2 1.1 1.0 1.3 1.5 1.5 1.5 1.5 D570
Weight loss on heating (72 h at 82°C), max % 0.3 0.4 0.6 0.8 1.5 1.8 2.0 1.2 2.0 2.0 2.0
5. Ordering Information
5.1 Purchase orders for, or inquiries about, the materials described in this specification shall identify the following:
5.1.1 The number of this specification and the required type and grade chosen from Table 1, for example, D787 Type 1, Grade
1.
5.1.2 Supplementary requirements in accordance with this specification if necessary.
5.1.3 Color and opacity within the limits defined in 6.4.
5.1.4 Particle form and size if choice is available.
5.1.5 Such other requirements as may be agreed between the seller and the purchaser.
5. Materials and Manufacture
5.1 Materials supplied under this specification shall be ethyl cellulose plastics in the form of pellets unless otherwise specified.
5.2 Material supplied in these forms shall be as uniform in composition and size and as free of contamination as can be achieved
by good manufacturing practice.
5.3 These materials maypossibly contain colorants in the nominal amounts ordinarily employed, but such additives shall not
alter the ability of the materials to meet the specified properties.employed. Only those materials of this kind that meet the properties
specified are covered by this standard.
5.4 The color and transparency or opacity of items fabricated under the conditions recommended by the manufacturer of the
material shall be comparable within commercial match tolerances to the color and transparency or opacity of samples submitted
in advance by the manufacturer and approved by the purchaser. by the manufacturer.
6. Physical Requirements
6.1 Test specimens of the material shall conform to the requirements prescribed in Table 1.
6.2 Molded specimens for those tests requiring them shall be prepared as described in Section 109.
7.3 Flow temperature of a given compound shall be within 65°C of the flow temperature designated in the contract or or
...