ASTM D1765-23b

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Designation: D1765 − 23a D1765 − 23b
Standard Classification System for
Carbon Blacks Used in Rubber Products
This standard is issued under the fixed designation D1765; 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 classification system covers the classification of rubber-grade carbon blacks by the use of a four-character nomenclature
system. The first character gives some indication of the influence of the carbon black on the rate of cure of a typical rubber
compound containing the black. The second character gives information on the average surface area of the carbon black. The last
two characters are assigned arbitrarily.
1.2 All rubber-grade carbon blacks for which a number is currently assigned at the time of publication of this classification system
are listed in Table 1 together with some of their typical properties. ASTM classification numbers (“N” or “S” designation) not listed
in Table 1 have either been withdrawn or are not currently assigned. The use of inactive or unassigned N or S designations is
prohibited until such a time as the designation is officially reactivated or assigned by Subcommittee D24.41
1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.
1.4 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, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.5 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:
D1508 Test Method for Carbon Black, Pelleted Fines and Attrition
D1510 Test Method for Carbon Black—Iodine Adsorption Number
D1513 Test Method for Carbon Black, Pelleted—Pour Density
D1514 Test Method for Carbon Black—Sieve Residue
D2414 Test Method for Carbon Black—Oil Absorption Number (OAN)
D3053 Terminology Relating to Carbon Black
D3265 Test Method for Carbon Black—Tint Strength
D3493 Test Method for Carbon Black—Oil Absorption Number of Compressed Sample (COAN)
D6556 Test Method for Carbon Black—Total and External Surface Area by Nitrogen Adsorption
This classification system is under the jurisdiction of ASTM Committee D24 on Carbon Black and is the direct responsibility of Subcommittee D24.41 on Carbon Black
Nomenclature and Terminology.
Current edition approved April 1, 2023Dec. 15, 2023. Published April 2023January 2024. Originally approved in 1965. Last previous edition approved in 2023 as
D1765 – 23.D1765 – 23a. DOI: 10.1520/D1765-23A.10.1520/D1765-23B.
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.
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D1765 − 23b
TABLE 1 Carbon Black Properties
NOTE 1—The iodine adsorption number and oil absorption number values represent target values. A target value is defined as an agreed upon value
on which producers center their production process and users center their specifications. All other properties shown are averages of consensus values
agreed upon by D24 from the typical values supplied by several one or more manufacturers. Typical properties are dependent upon the target values and
may vary from producer to producer at the same iodine adsorption and oil absorption numbers because of the differences in processing equipment.
A A
Target Values Typical Descriptive Values
Oil Absorption
No. Pour
Iodine Adsorp-
Oil Absorption NSA Multipoint STSA Tint
B Compressed Density,
tion No.,
ASTM No. D2414, D6556, D6556 Strength,
Sample, D1513,
D1510, –5 3 3 2 3 2
Classification 10 m /kg 10 m /kg 10 m /kg D3265
g/kg D3493, kg/m
3 2 2
(cm /100 g) (m /g) (m /g) %ITRB
–5 3 3
(mg/g)
10 m /kg (lb/ft )
(cm /100 g)
N110 145 113 97 127 115 123 345 (21.5)
N115 160 113 97 137 124 123 345 (21.5)
N120 122 114 99 126 120 129 345 (21.5)
N121 121 132 111 122 114 119 320 (20.0)
N125 117 104 89 122 121 125 370 (23.0)
N134 142 127 103 143 137 131 320 (20.0)
N135 151 135 117 141 . . . 119 320 (20.0)
N219 118 78 75 . . . . . . 123 440 (27.5)
N220 121 114 98 114 106 116 355 (22.0)
N231 121 92 86 111 107 120 400 (25.0)
N234 120 125 102 119 112 123 320 (20.0)
N293 145 100 88 122 111 120 380 (23.5)
N299 108 124 104 104 97 113 335 (21.0)
N326 82 72 68 78 76 111 455 (28.5)
N330 82 102 88 76 75 104 380 (23.5)
N335 92 110 94 85 85 110 345 (21.5)
N339 90 120 99 91 88 111 345 (21.5)
N343 92 130 104 96 92 112 320 (20.0)
N347 90 124 99 85 83 105 335 (21.0)
N351 68 120 95 71 70 100 345 (21.5)
N356 92 154 112 91 87 106
N358 84 150 108 80 78 98 305 (19.0)
N375 90 114 96 93 91 114 345 (21.5)
N539 43 111 81 39 38 . . . 385 (24.0)
N550 43 121 85 40 39 . . . 360 (22.5)
N630 36 78 62 32 32 . . . 500 (31.0)
N642 36 64 62 39 . . . . . .
N650 36 122 84 36 35 . . . 370 (23.0)
N660 36 90 74 35 34 . . . 440 (27.5)
N683 35 133 85 36 34 . . . 355 (22.0)
N750 27 120 81 27 26 . . . 360 (22.5)
N754 24 58 57 25 24 . . .
N762 27 65 59 29 28 . . . 515 (32.0)
N765 31 115 81 34 32 . . . 370 (23.0)
N772 30 65 59 32 30 . . . 520 (32.5)
N774 29 72 63 30 29 . . . 490 (30.5)
N787 30 80 70 32 32 . . . 440 (27.5)
N907 . . . 34 . . . 9 9 . . . 640 (40.0)
N908 . . . 34 . . . 9 9 . . . 355 (22.0)
N990 . . . 38 37 8 8 . . . 640 (40.0)
N991 . . . 35 37 8 8 . . . 355 (22.0)
A
See note above. See also Terminology D3053.
B
In general, Test Method D1510 can be used to estimate the surface area of furnace blacks but not channel, oxidized, and thermal blacks.
C
New numbers are marked to designate that the requestor has a one-year period, starting from the number’s approval date as shown in Footnote 1, to revise, by letter
ballot, target and typical values.
D1765 − 23b
D7854 Test Method for Carbon Black-Void Volume at Mean Pressure
3. Basis of Classification
3.1 The first character in the nomenclature system for rubber-grade carbon blacks is a letter indicating the effect of the carbon
black on the cure rate of a typical rubber compound containing the black. compound. The letter “N” is used to indicate a normal
curing rate typical of furnace blacks that have received no special modification to alter their influence on the rate of cure of rubber.
The letter “S” is used for channel blacks or for furnace blacks that have been modified to effectively reduce the curing rate of
rubber. Channel blacks characteristically impart a slower rate of cure to rubber compounds. Thus, the letter “S” designates a slow
cure rate. Blacks Carbon blacks may vary considerably in “curing rate” within each of the two letter classifications.
3.2 The second character in the system is a digit to designate the average surface area of the carbon black as measured by nitrogen
surface area. The surface area range of the carbon blacks has been divided into ten arbitrary groups, and each has been assigned
a digit to describe that group. These groups are as follows:
Average Nitrogen
Group No.
Surface Area, m /g
0 >150
1 121 to 150
2 100 to 120
...