ASTM E1556-98
(Specification)Standard Specification for Epoxy Resin System for Composite Skin, Honeycomb Sandwich Panel Repair
Standard Specification for Epoxy Resin System for Composite Skin, Honeycomb Sandwich Panel Repair
SCOPE
1.1 This specification covers the requirements for an epoxy resin system intended for the repair of sandwich panels for durable, rigidwall, relocatable shelters. It must be usable in a field environment and shall not require the use of special equipment such as autoclaves or presses. The epoxy system covered by this specification shall be usable for simultaneous impregnation of a wet-layup composite skin and bonding of that skin to a substrate honeycomb core. The material shall withstand exposure to temperatures from -54 to 93°C (-65 to 199°F) and high relative humidity, and also the combination of stress, temperature, and relative humidity that are expected to be encountered in service.
1.2 The values stated in SI units are to be regarded as standard where only SI units are given or where SI units are given first followed by inch-pound units; where inch-pound units are given first followed by SI units, the inch-pound units are to be regarded as the standard.
1.3 The following safety hazards caveat refers only to the test methods described in 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.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: E 1556 – 98 An American National Standard
Standard Specification for
Epoxy Resin System for Composite Skin, Honeycomb
Sandwich Panel Repair
This standard is issued under the fixed designation E 1556; 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.
1. Scope D 2584 Test Method for Ignition Loss of Cured Reinforced
Resins
1.1 This specification covers the requirements for an epoxy
D 2734 Test Methods for Void Content of Reinforced Plas-
resin system intended for the repair of sandwich panels for
tics
durable, rigidwall, relocatable structures. It must be usable in a
D 3165 Test Method for Strength Properties of Adhesives in
field environment and shall not require the use of special
Shear by Tension Loading of Single-Lap-Joint Laminated
equipment such as autoclaves or presses. The epoxy system
Assemblies
covered by this specification shall be usable for simultaneous
E 874 Practice for Adhesive Bonding of Aluminum Facings
impregnation of a wet-layup composite skin and bonding of
to Nonmetallic Honeycomb Core for Shelter Panels
that skin to a substrate honeycomb core. The material shall
E 1091 Specification for Nonmetallic Honeycomb Core for
withstand exposure to temperatures from −54 to 93°C (−65 to
Use in Shelter Panels
199°F) and high relative humidity, and also the combination of
2.2 Federal Specifications:
stress, temperature, and relative humidity that are expected to
PPP-B-566 Box, Folding, Paperboard
be encountered in service.
PPP-B-636 Box, Shipping, Fiberboard
1.2 The values stated in SI units are to be regarded as
PPP-B-676 Boxes, Set Up
standard where only SI units are given or where SI units are
2.3 Federal Standard:
given first followed by inch-pound units; where inch-pound
Fed. Std. No. 102 Preservation, Packaging, and Packing
units are given first followed by SI units, the inch-pound units
Levels
are to be regarded as the standard.
2.4 Military Specifications:
1.3 The following safety hazards caveat refers only to the
MIL-C-9084C Cloth, Glass, Finished for Epoxy Resin
test methods described in this specification. This standard does
Laminate
not purport to address all of the safety concerns, if any,
MIL-P-18177C Plastic Sheet, Laminated, Thermosetting,
associated with its use. It is the responsibility of the user of this
Glass-Fiber Base, Epoxy Resin
standard to establish appropriate safety and health practices
2.5 Military Standards:
and determine the applicability of regulatory limitations prior
MIL-STD-105 Sampling Procedures and Tables for Inspec-
to use.
tion by Attributes
2. Referenced Documents
MIL-STD-129 Marking for Shipment and Storage
2.1 ASTM Standards:
3. Physical Requirements
C 297 Test Method for Tension Strength of Flat Sandwich
2 3.1 Working Characteristics:
Constructions in Flatwise Plane
3.1.1 Application—The components of the epoxy resin shall
D 792 Test Methods for Density and Specific Gravity (Rela-
3 be readily hand-mixed to a smooth consistency suitable for
tive Density) of Plastics by Displacement
application. It shall be uniform and free of lumps. The resin
D 2344 Test Method for Apparent Interlaminar Shear
components, once mixed, shall not settle out. The epoxy
Strength of Parallel Fiber Composites by Short Beam
material shall be suitable for the wet-layup impregnation of
Method
MIL-C-9084C glass cloth and for application to core materials
over the temperature range of 16 to 38°C (60 to 100°F) and at
relative humidities of 30 to 75 %.
This specification is under the jurisdiction of ASTM Committee E-6 on 3.1.2 Application Life—The application life of a 200-g kit
Performance of Buildings and is the direct responsibility of Subcommittee E06.53
on Materials and Processes for Durable Rigidwall Relocatable Structures.
Current edition approved April 10, 1998. Published August 1998. Originally
Annual Book of ASTM Standards, Vol 08.02.
published as E 1556–93. Last previous edition E 1556–93a.
Annual Book of ASTM Standards, Vol 15.06.
Annual Book of ASTM Standards, Vol 15.03.
Annual Book of ASTM Standards, Vol 04.11.
Annual Book of ASTM Standards, Vol 08.01.
Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700
Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
E 1556
TABLE 1 Property Requirements for 24-h, 23°C Cure
A
Number of Average Must Exceed Minimum Must Exceed,
Property Test Condition
Specimens
MPa (psi) MPa (psi)
Tensile Lap Shear Strength in accordance 23°C (73°F), dry 5 6.9 (1000) 5.85 (850)
with 7.2.1, 7.3.1
Apparent Horizontal Shear Strength in 23°C (73°F), dry 5 15.5 (2250) 13.15 (1910)
accordance with 7.2.2, 7.3.2
A
All specimens tested must exceed these minimum values.
TABLE 2 Tensile Lap Shear Strength Requirements (See 7.3.1)
A
Average Must Exceed Minimum Must Exceed,
Number of
Test Condition
Specimens MPa (psi) MPa (psi)
−40°C (−40°F), dry 5 13.8 (2000) 11.7 (1700)
23°C (73°F), dry 5 13.8 (2000) 11.7 (1700)
B
93°C (200°F), wet 5 6.9 (1000) 5.9 (850)
A
All specimens tested must exceed these minimum values.
B
Wet 5 tested immediately after 30 days’ exposure to 60°C (140°F) and 95 to 100 % R.H.
TABLE 3 Apparent Horizontal Shear Strength Requirements
A
Number of Average Must Exceed Minimum Must Exceed,
Test Condition
Specimens MPa (psi) MPa (psi)
23°C (73°F), dry 5 31.0 (4500) 26.3 (3820)
B
93°C (200°F), wet 5 13.8 (2000) 11.7 (1700)
A
All specimens tested must exceed these minimum values.
B
Wet 5 tested immediately after 30 days exposure to 60°C (140°F) and 95 to 100 % R.H.
TABLE 4 Flatwise Tensile Strength Requirements
A
Number of Average Must Exceed Minimum Must Exceed,
Test Condition
Specimens MPa (psi) MPa (psi)
−40°C (−40°F), dry 5 2.8 (406) 2.4 (345)
23°C (73°F), dry 5 2.8 (406) 2.4 (345)
B
80°C (176°F), wet 5 1.38 (200) 1.17 (170)
A
All specimens tested must exceed these minimum values.
B
Wet 5 tested immediately after 30 days exposure to 60°C (140°F) and 95 to 100 % R.H.
of the mixed epoxy system shall be at least 60 min when tested viscosity exceeds 20 000 centipoise. The viscosity immediately
in accordance with 3.1.5. The epoxy shall be considered to after mixing shall not exceed 14 000 centipoise.
have reached the end of its application life when the viscosity
3.2 Mechanical Properties—Mechanical properties of test
of this 200-g quantity of mixed adhesive exceeds 20 000
specimens prepared and tested as specified in Section 7 shall
centipoise.
meet the respective requirements listed in Tables 2-4.
3.1.3 Curing—The epoxy system shall be capable of curing
3.3 Instruction Sheet—The manufacturer shall provide a
at 23 6 2°C (73 6 4°F) in 7 days, or for no longer than3hat
dated, coded and titled instruction sheet outlining instructions
a temperature of 60 to 66°C (140 to 151°F), with a curing
for use of the epoxy system in impregnating and bonding
pressure not to exceed 14 psig. In a 23°6 3°C cure, the curing
MIL-C-9084C glass composite skins to honeycomb cores
pressure is not required to be maintained after the first 24 h. In
(Specification E 1091, Types I or II). These instructions shall
a23 6 2°C cure, the epoxy material shall develop the property
be supplied by the manufacturer with the test report when
levels listed in Table 1 within the first 24 h of cure (see 7.3.5).
requesting qualification (see 6.3) and also with each shipment
In order to meet the requirements of this specification, the
of epoxy material (see 9.2). The following information shall be
property levels listed in Tables 2-4 must be achieved with the
included:
7-day cure at 23 6 2°C (73 6 4°F).
3.3.1 All of the information listed in 5.3.1-5.3.12.
3.1.4 Storage Life—The storage life period of the two parts
3.3.2 The application life of the mixed epoxy system at 23
of the epoxy resin system, when stored in airtight containers at
6 2°C (73 6 4°F) and 38 6 2°C (1006 4°F).
23°C (73°F), shall be at least 12 months from the date of
3.3.3 Mixing instructions shall be stated in detail for the
shipment when tested in accordance with 7.3.5.
epoxy resin system in the particular container supplied.
3.1.5 Viscosity—The viscosity of a 200-g kit of the mixed
3.3.4 Application, impregnating, and curing instructions,
resin system shall be determined at 23 6 2°C (73 6 4°F) using
including the spreading method, thickness range, and
a Brookfield viscometer with a No. 3 spindle at 20 rpm. A
temperature/relative humidity working limitations.
viscosity curve shall be determined by taking a reading
3.3.5 Material Safety Data Sheets and necessary safety
immediately after mixing, and every 5 min thereafter until the
precautions to be observed throughout all operations.
3.3.6 Any other pertinent information relative to the use and
storage of the two-part system (resin and curing agent) package
Normal failure modes are debonding along the core-skin interface or core
tearing but other failure modes may be encountered. (see 9.2).
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
E 1556
4. Significance and Use 5.3.3 Date of manufacture,
5.3.4 Manufacturer’s name and address,
4.1 Epoxy resin systems used in the repair of composite skin
5.3.5 Manufacturer’s batch/lot designation,
sandwich panels for durable, rigidwall, relocatable shelters
5.3.6 Contract number,
must have a combination of mechanical property levels and
5.3.7 Date of shipment,
environmental resistance that will assure long-term durability
5.3.8 Expiration dates when stored at 23 6 2°C (73 6 4°F),
of the skins and the skin-to-core adhesive bonds when exposed
5.3.9 Manufacturer’s recommended storage temperature,
to severe climatic exposures. In addition, these epoxy materials
5.3.10 Quantity required,
must have processability characteristics that permit their use in
5.3.11 Level of packaging and packing required, and
a variety of repair scenarios and environments.
5.3.12 Manufacturer’s certification that the batch and lot
4.2 Intended Use—Epoxy systems conforming to this speci-
meet the requirements of this specification.
fication are intended for use in the repair of honeycomb panels
at the maintenance field level. The material is intended for use
6. Quality Assurance Provisions
with MIL-C-9084C glass cloth.
6.1 Responsibility for Inspection—Unless otherwise speci-
4.2.1 This is a procurement control document for the
fied in the contract or purchase order, the supplier is respon-
procurement of the epoxy system and designers shall be aware
sible for the performance of all inspection requirements as
that the test values specified herein are based upon tests
specified herein. Except as otherwise specified in the contract
performed with specific glass-resin composite adherends and
or purchase order, the supplier is permitted to use any facility
shall not be used for design data.
suitable for the performance of the inspection requirements
4.2.2 Epoxy systems covered by this specification are not
specified herein, unless disapproved by purchaser. The pur-
intended for use in production bonding of sandwich construc-
chaser reserves the right to perform any of the inspections set
tion.
forth in the specification where such inspections are required to
ensure that supplies and services conform to prescribed re-
5. Material and Ordering Information
quirements.
5.1 General Description—The material shall be a two-part
6.2 Classification of Tests—The inspection and testing of
thermosetting epoxy system containing no asbestos, which
the epoxy system shall be classified as qualification tests (see
shall not have a deleterious effect on the components being
6.3) and quality conformance tests (see 6.4).
impregnated and bonded. It shall have physical characteristics
6.3 Qualification Tests:
that meet the requirements of Sections 3 and 6.
6.3.1 Sampling Instruction:
5.1.1 Formulation Changes—The epoxy material shall be
6.3.1.1 Epoxy Resin System Samples—The manufacturer
approved only for the formulation that has passed the qualifi-
shall submit two 1-qt samples of the base epoxy resin, along
cation tests and shall be used by the fabricator as approved.
with the necessary curing agent, from a single-numbered
Any changes by the manufacturer, such as the adding or
production batch of material being presented for qualification.
changing of pigments, hardeners, or fillers, or changes in the
The manufacturer shall submit two additional 200-g kits of the
type or method of manufacture, changes in formulation of the
two-part system (resin and curing agent) from the same
basic resin, or any other changes, shall be cause for designating
production batch for storage life tests (7.3.4). These four 200-g
the adhesive as a new product that shall not be considered
kit epoxy resin samples shall each be from a batch of most
approved. The changed epoxy resin system shall be given a
recent production-scale manufacture, and are not required to be
new code number and shall be resubmitted for approval under
from the same batch as that used in preparing the duplicate
this specification. A new instruction sheet for this reformulated
panels specified in 6.3.1.3. All samples shall be identified as to:
material shall be submitted by the manufacturer to the quali-
(a) Name and address of manufacturer,
fying activity for approval (see 3.3 and section 10.3.2.3).
(b) Manufacturer’s designation (trade name and code num-
5.1.2 Identification of Product—The manufacturer shall
ber),
identify each epoxy resin system submitted under this specifi-
(c) Type of epoxy resin,
cation according to the type of container furnished for it (see
(d) Batch number,
Section 9). In addition, the manufacturer shall designate each
(e) Date of manufacture,
epoxy system by a trade name and code number that shall be
(f) Date of submittal,
used to identify it.
(g) Expiration date, and
5.2 Qualification—In the case of epoxy systems for which
(h) Identification of agency submitting the samples.
the purchaser requires qualification, the procurement document
6.3.1.2 A statement indicating that the products have not
shall state that awards will be made only for epoxy systems that
been rebranded shall accompany the samples. If rebranded, the
are, at the time set for opening for bids, qualified, according to
...
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