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Scotch-WeldTM
Epoxy Adhesive
DP420 Black • DP420 NS Black • DP420 Off-White • DP420 LH
Technical Data April, 2019
Product Description 3M™ Scotch-Weld™ Epoxy Adhesives are high performance, two-part epoxy
adhesives offering outstanding shear and peel adhesion, and very high levels of
durability.
Features • High shear strength
• High peel strength
• Outstanding environmental
performance
• Easy mixing
• 20 minute worklife
• Controlled flow (3M™ Scotch-Weld™ Epoxy
Adhesive DP420 NS Black)
• Recognized as meeting UL 94 HB – Underwriters
Laboratory Horizontal Burn Flammability Test
(3M™ Scotch-Weld™ Epoxy Adhesive DP420
Off-White)
• Low halogen content (3M™ Scotch-Weld™
Epoxy Adhesive DP420 LH)
Typical Uncured
Physical Properties
Note: The following technical information and data should be considered representative
or typical only and should not be used for specification purposes.
Product
3M™ Scotch-Weld™ Epoxy Adhesive
DP420 Black
DP420 NS Black
DP420 Off-White
DP420 LH
Viscosity (approx.)
Base
20,000-50,000 cP
190,000-270,000 cP
20,000-50,000 cP
20,000-50,000 cP
@ 73°F (23°C)
Accelerator
8,000-14,000 cP
60,000-130,000 cP
8,000-14,000 cP
8,000-14,000 cP
Base Resin
Base
Accelerator
epoxy
amine
epoxy
amine
epoxy
amine
epoxy
amine
Color
Base
Accelerator
black
amber
black
amber
white
amber
white
amber
Net Weight
Base
9.3-9.7
9.4-9.8
9.3-9.7
9.3-9.7
Lbs./Gallon
Accelerator
9.0-9.4
9.1-9.5
9.0-9.4
9.0-9.4
Mix Ratio (B:A)
Volume
2:1
2:1
2:1
2:1
Weight
2:0.97
2:0.97
2:0.97
2:0.97
Worklife, 73°F (23°C)
20 g mixed
15 minutes
15 minutes
15 minutes
15 minutes
10 g mixed
20 minutes
20 minutes
20 minutes
20 minutes
5 g mixed
30 minutes
30 minutes
30 minutes
30 minutes
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Typical Cured
Properties
Note: The following technical information and data should be considered representative
or typical only and should not be used for specification purposes.
The properties of cured 3M™ Scotch-Weld™ Epoxy Adhesive DP420 NS Black
and 3M™ Scotch-Weld™ Epoxy Adhesive DP420 LH are expected to be similar to
the properties of 3M™ Scotch-Weld™ Epoxy Adhesive DP420 Black and 3M™
Scotch-Weld™ Epoxy Adhesive DP420 Off-White, respectively as described by
data in the following sections of this technical data sheet.
An exception to this is the concentration of halogens in 3M™ Scotch-Weld™
Epoxy Adhesive DP420 LH. 3M™ Scotch-Weld™ Epoxy Adhesive DP420 LH is
a form of 3M™ Scotch-Weld™ Epoxy Adhesive DP420 Off-White that can be
considered “low halogen”. Low halogen is defined by the Electrotechnical
Commission (IEC) 61249-2-21 standard as having less than 900 ppm chlorine,
900 ppm bromine, and less than 1500 ppm total chlorine and bromine.
3M™ Scotch-Weld™ Epoxy Adhesive DP420 LH Test Results
Halogens (determined by ion chromatography)
Total Chlorine (ppm)
Total Bromine (ppm)
Total Halogens (ppm)
720
<5
<800
Product
3M™ Scotch-Weld™
Epoxy Adhesive
DP420 Black
3M™ Scotch-Weld™
Epoxy Adhesive
DP420 Off-White
Physical
Color
Black
Opaque, off-white
Shore D Hardness
75-80
75-80
Thermal
Coefficient of Thermal
Expansion Below Tg
(in./in./°C) Above Tg
80 x 10
-6
194 x 10
-6
85 x 10
-6
147 x 10
-6
Thermal Conductivity
(btu - ft./ft.
2
- hr. - °F) @ 45°C
0.104
0.104
Electrical
Dielectric Strength (ASTM D 149)
888 volts/mil
690 volts/mil
Volume Resistivity (ASTM D 257)
1.6 x 10
15
ohm-cm
1.3 x 10
14
ohm-cm
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3M™ Scotch-Weld™
Epoxy Adhesive
DP420 Black • DP420 NS Black • DP420 Off-White • DP420 LH
Typical Curing
Characteristics
Note: The following technical information and data should be considered representative
or typical only and should not be used for specification purposes.
Rate of Strength Build-Up
Aluminum, Overlap Shear (7 mil Bondline) (ASTM D 1002-72)
Bonds Tested at 73°F (23°C)
3M™ Scotch-Weld™ Epoxy Adhesive DP420 Black
Time in Oven
Cure Temperature
73°F (23°C)
120°F
1
(49°C)
140°F
1
(60°C)
15 min.
NT
NT
3200
30
NT
2300
NT
60
NT
4700
4700
2 hr.
300
3
800
5
3000
6
3700
24
4500
1
This represents the oven temperature to which the bonds were subjected for the prescribed
time. The average bondline temperature during the cure time will be somewhat lower than
the oven temperature.
NOTE:
The data in this data sheet were generated using the 3M™ EPX Applicator System
equipped with an EPX static mixer, according to manufacturer’s directions. Thorough
hand-mixing will afford comparable results.
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Typical Adhesive
Performance
Characteristics
Note: The following technical information and data should be considered representative or
typical only and should not be used for specification purposes.
Substrates and Testing
A.
Overlap Shear (ASTM D 1002-72)
Overlap shear (OLS) strengths were measured on 1 in. wide 1/2 in. overlap specimens. These
bonds were made individually using 1 in. x 4 in. pieces of substrate except for aluminum. Two
panels 0.063 in. thick, 4 in. x 7 in. of 2024T-3 clad aluminum were bonded and cut into 1 in.
wide samples after 24 hours. The thickness of the bondline was 0.005-0.008 in. All strengths
were measured at 73°F (23°C) except where noted.
The separation rate of the testing jaws was 0.1 in. per minute for metals, 2 in. per minute for
plastics and 20 in. per minute for rubbers. The thickness of the substrates were: steel, 0.060 in.;
other metals, 0.05-0.064 in.; rubbers, 0.125 in.; plastics, 0.125 in.
B.
T-peel (ASTM D 1876-61T)
T-peel strengths were measured on 1 in. wide bonds at 73°F (23°C). The testing jaw separation
rate was 20 inches per minute. The substrates were 0.032 in. thick.
C.
Bell Peel (ASTM D 3167)
Bell peel strengths were measured on 1/2 in. wide bonds at the temperatures noted. The testing
jaw separation rate was 6 in. per minute. The bonds are made with 0.064 in. bonded to 0.025 in.
thick adherends.
D.
Cure Cycle
With the exception of Rate of Strength Build-Up Tests, all bonds, were cured 7 days at 73°F
(23°C) at 50% RH before testing or subjected to further conditioning or environmental aging.
Aluminum, Overlap Shear, at Temperature (PSI)
1
Represents time in test chamber oven before test.
Metals, Overlap Shear, Tested @ 73°F (23°C) (PSI)
3M™ Scotch-
Weld™ Epoxy
Adhesive DP420
Black
3M™ Scotch-
Weld™ Epoxy
Adhesive DP420
Off-White
3M™ Scotch-
weld™ Epoxy
Adhesive DP420NS
Black
Aluminum- Etched
4500
4500
4500
Oakite degrease
4000
3500
NT
MEK/abrade/MEK
2500
3500
3500
Cold Rolled Steel- Oakite degrease
—
4000
NT
MEK/abrade/MEK
2200
2700
2500
Copper- MEK/abrade/MEK
5000
4000
3000
Brass- MEK/abrade/MEK
2800
4100
3500
Stainless Steel- MEK/abrade/MEK
1800
1700
3900
Galvanized Steel- Hot dipped
2900
2000
NT
Electrodeposited
3000
2100
NT
3M™ Scotch-Weld™
Epoxy Adhesive DP420
Black
3M™ Scotch-Weld™
Epoxy Adhesive DP420
Off-White
3M™ Scotch-Weld™
Epoxy Adhesive
DP420NS Black
-67°F (-55°C)
4500
4500
4500
4500
73°F (23°C)
4500
4500
4500
180°F (82°C) (15 min.)
1
1260
450
860
1400
1600
21
(30 min.)
1
2250
700
1400
(60 min.)
1
2980
750
1600
(4 hr.)
1
2690
2500
2100
250°F (121°C) (15 min.)
1
570
200
350
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3M™ Scotch-Weld™
Epoxy Adhesive
DP420 Black • DP420 NS Black • DP420 Off-White • DP420 LH
NT: Not tested
Typical Adhesive
Performance
Characteristics
(continued)
Note: The following technical information and data should be considered representative
or typical only and should not be used for specification purposes.
Substrates and Testing (continued)
Aluminum, T-Peel (PIW), at Temperature
3M™ Scotch-Weld™
Epoxy Adhesive
DP420 Black
3M™ Scotch-Weld™
Epoxy Adhesive
DP420 Off-White
-67°F (-55°C)
9.3
5-10
73°F (23°C)
50
50
180°F (82°C)
20
3-5
Metals, T-Peel, Tested @ 73°F (23°C) (PIW)
3M™ Scotch-
Weld™ Epoxy
Adhesive DP420
Black
3M™Scotch-
Weld™ Epoxy
Adhesive DP420
Off-White
Aluminum, etched 17-20 mil bondline
60
50
5-8 mil bondline
50
40
Cold Rolled Steel 17-20 mil bondline
40
40
Oakite degreased
MEK/abrade/MEK
25
25
Aluminum, Bell Peel (PIW), at Temperature
3M™ Scotch-Weld™
Epoxy Adhesive
DP420 Black
3M™ Scotch-Weld™
Epoxy Adhesive DP420
Off-White
3M™ Scotch-Weld™
Epoxy Adhesive
DP420NS Black
-67°F (-55°C)
73°F (23°C)
180°F (82°C)
20
82
18
not tested
Not tested
58
Not tested
Other Substrates, Overlap Shear Tested @ 73°F (23°C) (PSI)
Substrate
Surf. Prep. 11
3M Scotch-Weld 3M Scotch-Weld
Epoxy Adhesive Epoxy Adhesive
DP420 Black DP420 Off-White
Surf. Prep. 22
3M Scotch-Weld 3M Scotch-Weld
Epoxy Adhesive Epoxy Adhesive
DP420 Black DP420 Off White
3M Scotch-Weld
Epoxy Adhesive
DP420NS Black
ABS
450
320
550
500
870
PVC
4003
220
3603
300
NT
Polycarbonate
440
400
450
550
470
Polyacrylic
190
230
450
280
NT
Polystryene
380
350
580
380
NT
FRP
600
350
11003
13003
3700
Phenolic
14003
14003
13003
14003
1170
SBR/Steel
Neoprene/Steel
70
1503
1803
1503
NT
80
40
100
80
NT
1Isopropyl Alcohol Wipe. See Surface Preparation Section D for additional information.
2Isopropyl Alcohol/Abrade/Isopropyl Alcohol: See Surface Preparation Section E for additional information.
3Substrate failure.
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Adhesive*
6mm Nozzle
gms/minute
10mm Nozzle
gms/minute
3M™ Scotch-Weld™ Epoxy Adhesive
29.6
113
DP420 Black
3M™ Scotch-Weld™ Epoxy Adhesive
31.1
132
DP420 Off-White
Typical Adhesive
Performance
Characteristics
(continued)
Note: The following technical information and data should be considered representative
or typical only and should not be used for specification purposes.
Substrates and Testing (continued)
Environmental Resistance
Aluminum (Etched)
Measured by Overlap Shear Tested @ 73°F (23°C) (PSI)1 (ASTM D 1002-72)
Environment
Condition
3M™ Scotch-Weld™
Epoxy Adhesive
DP420 Black
3M™ Scotch-Weld™
Epoxy Adhesive
DP420 Off-White
3M™ Scotch-Weld™
Epoxy Adhesive
DP420NS Black
73°F (23°C)/50% RH
30 d
2
4900
5100
4590
47
Distilled Water
30 d, i
3
4200
4700
4790
4400
Water Vapor
120°F (49°C)/100% RH, 30 d
200°F (93°C)/100% RH, 14 d
4000
4000
4700
3000
4410
3780
Antifreeze/H2O (50/50)
180°F (82°C), 30 d, i
3000
4200
4240
Isopropyl Alcohol
73°F (23°C), 30 d, i
4500
5300
5180
Methyl Ethyl Ketone
73°F (23°C), 30 d, i
3500
4600
NT
Salt Spray (5%)
95°F (35°C), 30 d
NT
5100
NT
Skydrol LD-4
150°F (66°C), 30 d, i
4000
5400
4810
1
Data reported are actual values from the lots tested and may be higher than values published elsewhere in this
data sheet.
2
d = days
3
i = immersion
3M™ EPX
Pneumatic Applicator
Delivery Rates
200 ml Applicator – Maximum Pressure 58 psi
*Tests were run at a temperature of 70°F ± 2°F (21°C ± 1°C) and at maximum applicator pressure.
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3M™ Scotch-Weld™
Epoxy Adhesive
DP420 Black • DP420 NS Black • DP420 Off-White • DP420 LH
Handling/Application
Information Directions for Use
3M™ Scotch-Weld™ Epoxy Adhesive DP420 is supplied in dual syringe plastic duo-
pak cartridges as part of the 3M™ EPX Applicator System. The duo-pak cartridges are
supplied in 50 ml, 200 ml and 400 ml configurations. To use the EPX cartridge system
simply insert the duo-pak cartridge into the EPX applicator. Next, remove the duo-pak
cartridge cap and expel a small amount of adhesive to be sure both sides of the duo-
pak cartridge are flowing evenly and freely. If simultaneous mixing of Part A and Part
B is desired, attach the EPX mixing nozzle to the duo-pak cartridge and begin
dispensing the adhesive.
When mixing Part A and Part B manually the components must be mixed in the
ratio indicated in the typical uncured properties section of this data sheet. Complete
mixing of the two components is required to obtain optimum properties.
Two-part mixing/proportioning/dispensing equipment is available for intermittent or
production line use. These systems are ideal for line uses because of their variable
shot size and flow rate characteristics and are adaptable to most applications.
Apply adhesive to clean, dry surfaces, joint parts and secure until adhesive sets (see
rate of strength build up).
Surface Preparation The following surface preparations were used for substrates described in this Technical
Data Sheet.
A. Aluminum Etch
Optimized FPL Etch - 3M (test method C-2803)
1. Alkaline degrease – Oakite 164 solution (9-11 oz./gallon water) at 190°F ±
10°F (88°C ± 5°C) for 10-20 minutes. Rinse immediately in large quantities
of cold running water (3M test method C-2802).
2. Optimized FPL Etch Solution (1 liter):
Material Amount
Distilled Water 700 ml plus balance of liter (see below)
Sodium Dichromate 28 to 67.3 grams
Sulfuric Acid 287.9 to 310.0 grams
Aluminum Chips 1.5 grams/liter of mixed solution
To prepare 1 liter of this solution, dissolve sodium dichromate in 700 ml of
distilled water. Add sulfuric acid and mix well. Add additional distilled water
to fill to 1 liter. Heat mixed solution to 66 to 71°C (150 to 160°F). Dissolve
1.5 grams of 2024 bare aluminum chips per liter of mixed solution. Gentle
agitation will help aluminum dissolve in about 24 hours.
To FPL etch panels, place them in the above solution at 150 to 160°F (66 to
71°C) for 12 to 15 minutes.
Note: Review and follow precautionary information provided by chemical
suppliers prior to preparation of this etch solution.
3. Rinse immediately in large quantities of clear running tap water.
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Surface Preparation
(continued) 4. Dry – air dry approximately 15 minutes followed by force dry at 140°F
(60°C) maximum for 10 minutes (minimum).
5. Both surface structure and chemistry play a significant role in determining the
strength and permanence of bonded structures. It is therefore advisable to
bond or prime freshly primed clean surfaces as soon as possible after surface
preparation in order to avoid contamination and/or mechanical damage.
Please contact your 3M sales representative for primer recommendations.
B. Oakite Degrease
Oakite 164 solutions (9-11 oz./gallon of water) at 190°F ± 10°F (88°C ± 5°C) for 2
minutes. Rinse immediately in large quantities of cold running water.
C. MEK/Abrade/MEK
Wipe surface with a methyl ethyl ketone (MEK) soaked swab, abrade and wipe
with a MEK soaked swab.* Allow solvent to evaporate before applying adhesive.
*Note: When using solvents, extinguish all ignition sources, including pilot lights,
and follow the manufacturer’s precautions and directions for use.
D. Isopropyl Alcohol Wipe Only Surface Preparation
Wipe surface with an isopropyl alcohol soaked swab.* Allow solvent to evaporate
before applying adhesive.
*Note: When using solvents, extinguish all ignition sources, including pilot lights,
and follow the manufacturer’s precautions and directions for use.
E. Isopropyl Alcohol/Abrade/Isopropyl Alcohol Surface Preparation
Wipe surface with an isopropyl alcohol soaked swab, abrade using clean fine grit
abrasives, and wipe with an isopropyl alcohol soaked swab.* Then allow solvent
to evaporate before applying adhesive.
*Note: When using solvents, extinguish all ignition sources, including pilot lights,
and follow the manufacturer’s precautions and directions for use.
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3M™ Scotch-Weld™
Epoxy Adhesive
DP420 Black • DP420 NS Black • DP420 Off-White • DP420 LH
Storage Store products at 60-80°F (15-27°C) for maximum shelf life.
Shelf Life These products have a shelf life of 24 months from date of manufacture in original
containers at room temperature
Precautionary
Information
Refer to Product Label and Material Safety Data Sheet for health and safety information before using this
product. For additional health and safety information, call 1-800-364-3577 or (651) 737-6501.
Technical Information The technical information, guidance, and other statements contained in this document or otherwise
provided by 3M are based upon records, tests, or experience that 3M believes to be reliable, but the
accuracy, completeness, and representative nature of such information is not guaranteed. Such
information is intended for people with knowledge and technical skills sufficient to assess and apply
their own informed judgment to the information. No license under any 3M or third party intellectual
property rights is granted or implied with this information.
Product Selection and Use Many factors beyond 3M’s control and uniquely within user’s knowledge and control can affect the use
and performance of a 3M product in a particular application. As a result, customer is solely responsible
for evaluating the product and determining whether it is appropriate and suitable for customer’s
application, including conducting a workplace hazard assessment and reviewing all applicable
regulations and standards (e.g., OSHA, ANSI, etc.). Failure to properly evaluate, select, and use a 3M
product and appropriate safety products, or to meet all applicable safety regulations, may result in injury,
sickness, death, and/or harm to property.
Warranty,
Limited Remedy,
and Disclaimer
Unless a different warranty is specifically stated on the applicable 3M product packaging or product
literature (in which case such warranty governs), 3M warrants that each 3M product meets the
applicable 3M product specification at the time 3M ships the product. 3M MAKES NO OTHER
WARRANTIES OR CONDITIONS, EXPRESS OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
ANY IMPLIED WARRANTY OR CONDITION OF MERCHANTABILITY, FITNESS FOR A
PARTICULAR PURPOSE, OR ARISING OUT OF A COURSE OF DEALING, CUSTOM, OR USAGE
OF TRADE. If a 3M product does not conform to this warranty, then the sole and exclusive remedy
is, at 3M’s option, replacement of the 3M product or refund of the purchase price.
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liable for any loss or damage arising from or related to the 3M product, whether direct, indirect, special,
incidental, or consequential (including, but not limited to, lost profits or business opportunity), regardless
of the legal or equitable theory asserted, including, but not limited to, warranty, contract, negligence, or
strict liability.
ISO 9001: 2008
This Industrial Adhesives and Tapes Division product was manufactured under a 3M quality system registered to ISO 9001: 2008 standards.
Industrial Adhesives and Tapes Division
3M Center, Building 225-3S-06
St. Paul, MN 55144-1000
800-362-3550 • 877-369-2923 (Fax)
www.3M.com/structuraladhesives
3M and Scotch-Weld are
trademarks of 3M Company.
©3M 2012 78690097106