HMC Electronics 40840 User Manual

Technical Data Sheet

LOCTITE®408™

June-2007

PRODUCT DESCRIPTION

LOCTITE®408™ provides the following product
characteristics:

Technology Cyanoacrylate
Chemical Type Alkoxyethyl cyanoacrylate
Appearance (uncured) Transparent, colorless to straw

colored liquid

LMS

Components One part - requires no mixing
Viscosity Very low

Cure Humidity
Application Bonding

Key Substrates Metals, Plastics and Elastomers

LOCTITE®408™ has low odor and low blooming properties
and is particularly suitable for applications where vapor control
is difficult. The product provides rapid bonding of a wide range
of materials, including metals, plastics and elastomers.
LOCTITE®408™ is particularly suited for bonding porous or
absorbent materials such as wood, paper, leather and fabric.

TYPICAL PROPERTIES OF UNCURED MATERIAL

Specific Gravity @ 25 °C 1.1
Flash Point - See MSDS
Viscosity, Cone & Plate, mPa·s (cP):

Temperature: 25 °C, Shear Rate: 3,000 s

-1

4 to 10

LMS

Viscosity, Brookfield - LVF, 25 °C, mPa·s (cP):

Spindle 1, speed 60 rpm 4 to 10

TYPICAL CURING PERFORMANCE

Under normal conditions, the atmospheric moisture initiates the
curing process. Although full functional strength is developed
in a relatively short time, curing continues for at least 24 hours
before full chemical/solvent resistance is developed.

Cure Speed vs. Substrate

The rate of cure will depend on the substrate used. The table
below shows the fixture time achieved on different materials
at 22 °C / 50 % relative humidity. This is defined as the time to
develop a shear strength of 0.1 N/mm².

Fixture Time, seconds:

Steel 30 to 120
Aluminum <3
Zinc dichromate 10 to 20
Neoprene <5
Rubber, nitrile <5
ABS 5 to 10
PVC 15 to 30
Polycarbonate 10 to 15
Phenolic 5 to 15
Wood (pine) 10 to 20
Leather 5 to 10

Cure Speed vs. Bond Gap

The rate of cure will depend on the bondline gap. Thin bond
lines result in high cure speeds, increasing the bond gap will
decrease the rate of cure.

Cure Speed vs. Humidity

The rate of cure will depend on the ambient relative
humidity. The best results are achieved when the relative
humidity in the working environment is 40% to 60% at 22°C.
Lower humidity leads to slower cure. Higher humidity
accelerates it, but may impair the final strength of the bond.

Cure Speed vs. Activator

Where cure speed is unacceptably long due to large gaps,
applying activator to the surface will improve cure speed.
However, this can reduce ultimate strength of the bond and
therefore testing is recommended to confirm effect.

TYPICAL PROPERTIES OF CURED MATERIAL

Cured for 1 week @ 22 °C

Physical Properties:

Coefficient of Thermal Expansion, ISO 11359-2, K

-1

476×10

-6

Coefficient of Thermal Conductivity, ISO 8302,
W/(m·K)

0.26

Glass Transition Temperature, ISO 11359-2, °C 172

Electrical Properties:

Volume Resistivity, IEC 60093, Ω·cm 130×10

15

Surface Resistivity, IEC 60093, Ω 11.9×10

15

Dielectric Breakdown Strength, IEC 60243-1, kV/mm 25
Dielectric Constant / Dissipation Factor, IEC 60250:

1-kHz 4.57 / 0.03
1-MHz 4.08 / 0.03
10-MHz 3.97 / 0.04

TYPICAL PERFORMANCE OF CURED MATERIAL

Adhesive Properties

Cured for 10 seconds @ 22 °C

Tensile Strength, ISO 6922:

Buna-N N/mm² ≥4.5

LMS

(psi) (≥652)

Cured for 72 hours @ 22 °C

Tensile Strength, ISO 6922:

Buna-N N/mm² 9 to 15

(psi) (1,300 to 2,200)

Steel (grit blasted) N/mm² 12 to 20

(psi) (1,700 to 2,900)

Lap Shear Strength, ISO 4587:

Steel (grit blasted) N/mm² 17 to 23

(psi) (2,500 to 3,300)

Aluminum (etched) N/mm² 4 to 17

(psi) (580 to 2,500)

Zinc dichromate N/mm² 0.5 to 3

(psi) (70 to 440)

ABS N/mm² 8 to 11

(psi) (1,200 to 1,600)

PVC N/mm² 1 to 5

(psi) (150 to 730)

Documentation Provided By HMC Electronics

33 Springdale Ave. Canton, MA 02021

http://www.hmcelectronics.com

[phone]

TDS LOCTITE®408™, June-2007

Phenolic N/mm² 1 to 3

(psi) (150 to 440)

Polycarbonate N/mm² 6 to 11

(psi) (870 to 1,600)

Nitrile N/mm² 0.5 to 1.5

(psi) (70 to 220)

Neoprene N/mm² 0.5 to 1.5

(psi) (70 to 220)

TYPICAL ENVIRONMENTAL RESISTANCE

Cured for 1 week @ 22 °C

Lap Shear Strength, ISO 4587:

Steel (grit blasted)

Hot Strength

Tested at temperature

% Strength @ 22 °C

Temperature, °C

140

120

100

80

60

40

20

0

-40 -20 0 20 40 60 80 100 120

Heat Aging

Aged at temperature indicated and tested @ 22 °C

% Initial Strength @ 22 °C

Exposure Time, hours

125

100

75

50

25

0

0 1000 2000 3000 4000 5000

100 °C

80 °C

60 °C

Chemical/Solvent Resistance

Aged under conditions indicated and tested @ 22 °C.

% of initial strength

Environment °C 100 h 500 h 1000 h 5000 h

Motor oil 40 85 75 60 55

Unleaded gasoline 22 90 80 75 65

Ethanol 22 100 90 110 110

Isopropanol 22 95 100 100 120

Water 22 65 30 30 5

98% RH 40 45 40 35 0

Lap Shear Strength, ISO 4587:

Polycarbonate

% of initial strength

Environment °C 100 h 500 h 1000 h 5000 h

Air 22 75 60 65 75

98% RH 40 85 70 80 85

GENERAL INFORMATION
This product is not recommended for use in pure oxygen

and/or oxygen rich systems and should not be selected as
a sealant for chlorine or other strong oxidizing materials

For safe handling information on this product, consult the
Material Safety Data Sheet (MSDS).

Directions for use

1.

Bond areas should be clean and free from grease. Clean
all surfaces with a Loctite®cleaning solvent and allow to
dry.

2.

Loctite®Primer may be applied to the bond area. Avoid
applying excess Primer. Allow the Primer to dry.

3.

LOCTITE®Activator may be used if necessary. Apply the
LOCTITE®Activator to one bond surface (do not apply
activator to the primed surface where Primer is also
used). Allow the Activator to dry.

4. Apply adhesive to one of the bond surfaces (do not apply
the adhesive to the activated surface). Do not use items
like tissue or a brush to spread the adhesive. Assemble
the parts within a few seconds. The parts should be
accurately located, as the short fixture time leaves little
opportunity for adjustment.

5.

LOCTITE® Activator can be used to cure fillets of product
outside the bond area. Spray or drop the activator on the
excess product.

6. Bonds should be held fixed or clamped until adhesive has
fixtured.

7. Product should be allowed to develop full strength before
subjecting to any service loads (typically 24 to 72 hours
after assembly, depending on bond gap, materials and
ambient conditions).

Henkel Loctite Americas
+860.571.5100

Henkel Loctite Europe

+49.89.9268.0

Henkel Loctite Asia Pacific

+81.45.758.1810

For the most direct access to local sales and technical support visit: www.loctite.com

Documentation Provided By HMC Electronics

33 Springdale Ave. Canton, MA 02021

http://www.hmcelectronics.com

[phone]