Standard Specification for Epoxy (Flexible) Adhesive for Bonding Metallic and Nonmetallic Materials

ABSTRACT
The specification covers a two-part modified epoxy paste adhesive for bonding metallic and nonmetallic materials. The adhesive should be suitable for forming bonds that can withstand environmental exposure to a certain temperature range when exposed to an expected combination of stress, temperature, and relative humidity to be encountered in service. Two types of adhesive shall be classified according to composition. Type I which consists of two-part kits of liquid base and modified amide liquid accelerator. Type I is further subdivided into two grades: Grade 1 with low viscosity and Grade 2 with high viscosity. The other classification is Type II which consists of premixed, frozen, Type I, Grade 1 or Type I, Grade 2. Different tests shall be conducted in order to determine the following mechanical properties of the adhesives: room-temperature shear, high-temperature shear, low-temperature shear, room-temperature Shore D hardness, room-temperature T-peel, and outgassing characteristics such as total mass loss and vacuum condensable material.
SCOPE
1.1 The specification covers a two-part modified epoxy paste adhesive for bonding metallic and nonmetallic materials. The adhesive should be suitable for forming bonds that can withstand environmental exposure to temperatures from -184 to 82 °C (-300 to 180 °F) when exposed to an expected combination of stress, temperature, and relative humidity to be encountered in service.
Note 1-When coordinated through the Department of Defense (DoD) and the National Aeronautics and Space Administration (NASA), this practice will be a direct replacement of MIL-A-82720 (OS), MIS-26872 and MSFC-SPEC-2037.
1.2 The values stated in SI units or inch-pound units are to be regarded separately as standard. Within the text, the inch-pound units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with this specification.
1.3 The following precautionary statement pertains to the test method portion only, Section 8, 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 and health practices and determine the applicability of regulatory limitations prior to use.

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Publication Date
31-Mar-2005
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ASTM D6412/D6412M-99(2005) - Standard Specification for Epoxy (Flexible) Adhesive for Bonding Metallic and Nonmetallic Materials
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:D6412/D6412M −99(Reapproved2005)
Standard Specification For
Epoxy (Flexible) Adhesive For Bonding Metallic And
Nonmetallic Materials
This standard is issued under the fixed designation D6412/D6412M; 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.
1. Scope Chromium-Nickel Steel Plate, Sheet, and Strip
B209 Specification for Aluminum and Aluminum-Alloy
1.1 The specification covers a two-part modified epoxy
Sheet and Plate
paste adhesive for bonding metallic and nonmetallic materials.
D907 Terminology of Adhesives
The adhesive should be suitable for forming bonds that can
D1002 Test Method for Apparent Shear Strength of Single-
withstand environmental exposure to temperatures from –184
Lap-Joint Adhesively Bonded Metal Specimens by Ten-
to 82 °C (–300 to 180 °F) when exposed to an expected
sion Loading (Metal-to-Metal)
combination of stress, temperature, and relative humidity to be
D1876 Test Method for Peel Resistance of Adhesives (T-
encountered in service.
Peel Test)
NOTE 1—When coordinated through the Department of Defense (DoD)
D2240 Test Method for Rubber Property—Durometer Hard-
and the National Aeronautics and Space Administration (NASA), this
ness
practice will be a direct replacement of MIL-A-82720 (OS), MIS-26872,
D2393 Test Method for Viscosity of Epoxy Resins and
and MSFC-SPEC-2037.
Related Components (Withdrawn 1992)
1.2 The values stated in SI units or inch-pound units are to
D2651 GuideforPreparationofMetalSurfacesforAdhesive
be regarded separately as standard. Within the text, the
Bonding
inch-pound units are shown in brackets. The values stated in
D3951 Practice for Commercial Packaging
each system are not exact equivalents; therefore, each system
D4142 Guide for Testing Epoxy Resins
must be used independently of the other. Combining values
E595 Test Method for Total Mass Loss and Collected Vola-
from the two systems may result in nonconformance with this
tile Condensable Materials from Outgassing in a Vacuum
specification.
Environment
1.3 The following precautionary statement pertains to the
2.2 National Aeronautics and Space Administration
test method portion only, Section 8, of this specification: This
(NASA):
standard does not purport to address all of the safety concerns,
JSC Sp-R-0022 General Specification,Vacuum Stability Re-
if any, associated with its use. It is the responsibility of the user
quirement of Polymeric Material for Spacecraft Applica-
of this standard to establish appropriate safety and health
tion
practices and determine the applicability of regulatory limita-
MSFC-HDBK-527/JSC-09604 Material Selection List for
tions prior to use.
Hardware Systems
GSFC RP 1124 Outgassing Data for Selecting Spacecraft
2. Referenced Documents
Materials
2.1 ASTM Standards:
NOTE 2—Copies of specifications, standards, drawings and publications
A109/A109M Specification for Steel, Strip, Carbon (0.25
required by suppliers in connection with specific purchases should be
Maximum Percent), Cold-Rolled
obtained from the purchaser or as directed by his contracting officer.
A167 Specification for Stainless and Heat-Resisting
3. Terminology
3.1 Definitions—Many terms in this specification are de-
This specification is under the jurisdiction of ASTM Committee D14 on
fined in Terminology D907.
Adhesives and is the direct responsibility of subcommittee D14.80 on Metal
Bonding Adhesives.
3.2 Definitions of Terms Specific to This Standard:
Current edition approved April 1, 2005. Published June 2005. Originally
approved in 1999. Last previous edition approved in 1999 as D6412/D6412M - 99.
DOI: 10.1520/D6412_D6412M-99R05.
2 3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or The last approved version of this historical standard is referenced on
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM www.astm.org.
Standards volume information, refer to the standard’s Document Summary page on Unless otherwise indicated, copies of the above documents are available from
the ASTM website. ant NASA installation library or document repository.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6412/D6412M−99(2005)
3.2.1 epoxy-polyamide high viscosity adhesive, n—anepoxy 7.3 Processing—Methods of specimen surface preparation,
paste base (B) and a modified amide paste accelerator (A) that is, cleaning and etching adherends, cure time, temperature
when mixed in a proper ratio results in a viscous paste. and pressure shall be in accordance with the manufacturer’s
recommendation.
3.2.2 epoxy-polyamide low viscosity adhesive, n—an epoxy
liquid base (B) and a modified amide liquid accelerator (A)
7.4 The physical, mechanical and outgassing properties of
when mixed in a proper ratio results in a viscous liquid.
the adhesive shall meet the requirements specified in Table 1.
Although,itisnotlistedinTable1,TypeIImaterialsshallmeet
4. Significance and Use
the same requirements as Type I materials.
4.1 General—This specification provides testing procedures
8. Test Methods
and specimen requirements to differentiate between the physi-
cal and adhesive bonding properties of two types of epoxy-
8.1 Qualification Tests—Forqualification,theadhesiveshall
polyamide adhesive.
be tested using the tests described in this section. Test methods
and requirements are included in Table 1.
5. Classification
8.2 Preparation of Test Specimens:
5.1 Theepoxy-polyamideadhesiveshallbefurnishedasone
8.2.1 Tensile Shear:
of the following types:
8.2.1.1 Adherend—The metal bonded shall be 6061-T6 or
5.1.1 Type I—Consists of two-part kits of Part B, base and
2024-T3 aluminum alloy.
Part A, accelerator.
NOTE 3—The use of steel substrates for the evaluation and lot
5.1.1.1 Grade 1—The high viscosity adhesive system is
acceptance of the material is optional at the discretion of the procuring
composed of an epoxy base (B) and a modified polyamide
agency. Use Specification A109/A109M Grade 2 Steel or Specification
accelerator (A).
A167, Type 302 corrosion resistant steel.
5.1.1.2 Grade 2—The low viscosity adhesive system is
8.2.1.2 Surface Treatment—Adherend surfaces shall be
composed of an epoxy liquid base (B) and a modified poly-
cleaned and etched in accordance with Guide D2651.
amide liquid accelerator (A).
8.2.1.3 Cure—Cure time, temperature and pressure shall be
5.1.2 Type II—Consists of premixed, frozen, Type I, Grade
in accordance with the adhesive manufacturer’s recommenda-
1 or Type I, Grade 2.
tion.
6. Ordering Information
NOTE 4—Test panels or specimens, or both, other than the breakaway
type shall be cut in such a manner that minimum vibration or heat is
6.1 Procurement Documents—Purchasers may select any of
generated during the cutting operation.
the desired options offered herein and the procurement docu-
NOTE 5—Adhesive bondline thickness for tensile shear specimens shall
ments should specify the following:
be 0.05 to 0.13 mm [0.002 in. to 0.005 in.] and 0.25 to 0.43 mm [0.010 to
6.1.1 Title, number and dated revision letter of this
0.017 in.] for T-Peel specimens. Control of bondline thickness shall be
specification, accomplished by placing two lengths of appropriate diameter stainless
wire [0.13 mm for tensile shear and 0.43 mm forT-Peel] in the lengthwise
6.1.2 Adhesive type and grade numbers,
direction on the specimen bond area during the adhesive bonding
6.1.3 Amounts and unit quantities of adhesive required,
operation; the use of the same diameter glass beads approximately 0.5 %
6.1.4 Curing conditions,
by weight, thoroughly mixed in the adhesive may also be used to maintain
6.1.5 Level of Packaging and packing required, and
uniform bondine thickness.
6.1.6 Whether or not qualification (see 6.2) is necessary.
8.2.2 Hardness specimens shall be prepared using a mixture
6.2 Qualification—In the case the adhesives for which the of resin and catalyst for Type I Grades 1 or 2 in the ratios
purchaser requires qualification, the procurement documents
specified by the manufacturer or Type II premixed. Pour the
should state that the awards will be made only for adhesives thoroughly mixed material into an aluminum foil cup approxi-
that are qualified at the time set for opening of bids.
mately 7.6 cm [3.0 in.] in diameter to a minimum thickness of
6.3 mm [0.25 in.]; cure per manufacturer’s recommendation.
7. Test Requirements
8.3 Test Procedures:
7.1 Material—The adhesive shall be thermosetting and,
8.3.1 Room-Temperature Tensile Shear—Subject at least
when tested using the tests described in Section
...

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