3M 3738

Harmonization Code : 3214.10.00 | Putty and other mastics | Resin cements, caulking compounds and other mastics

3M 3738

Main features

  • 2,875 cP Melt Viscosity at 191 deg C
  • 50-Second Open Time
  • 375 psi Douglas Fir Shear

Product Description

3M Hot Melt Adhesive 3738 is a tan, 100% solids thermoplastic hot-melt adhesive for bonding wood, corrugated materials, selected plastics, and foundry sand cores. The recommended application range is 177 to 196 deg C, with a typical viscosity of 2,875 cP at 191 deg C by Brookfield Thermocel testing. Typical open time is 50 seconds for a 3.2 mm bead on a nonmetallic surface at 24 deg C. The adhesive sets as it cools, with typical Douglas fir-to-Douglas fir overlap shear of 375 psi. Its typical temperature-resistance result is 54 deg C under a 14 kPa dead load.

Key features

  • 2,875 cP application viscosity: Typical viscosity at 191 deg C is measured with Brookfield Thermocel spindle 27 at 10 rpm.
  • 50-second open time: This typical maximum application-to-joining interval applies to a 3.2 mm bead on a nonmetallic surface at 24 deg C.
  • 375 psi wood overlap shear: This typical bond-strength result applies specifically to Douglas fir bonded to Douglas fir.

Applications

Foundry sand cores; cabinetry and woodworking; corrugated packaging; furniture and upholstery; point-of-purchase displays; sound damping; general industrial assembly.

Technical Specifications

General Properties
Color
The color
Tan
Density (g)
0.95 g/cm3
Physical Properties
Open time
0.83 minutes
Viscosity
Viscosity is a measurement of a fluid’s resistance to flow. Viscosity is commonly measured in centiPoise (cP). One cP is defined as the viscosity of water and all other viscosities are derived from this base. MPa is another common unit with a 1:1 conversion to cP. A product like honey would have a much higher viscosity -around 10,000 cPs- compared to water. As a result, honey would flow much slower out of a tipped glass than water would. The viscosity of a material can be decreased with an increase in temperature in order to better suit an application
2,875 mPa.s
Thermal Properties
Flash Point
The flashpoint of a solvent is the lowest possible temperature at which it can vaporize to form an ignitable vapor. Flashpoint is often confused with “autoignition temperature”, which is the temperature at which a solvent ignites without an ignition source.
288 °C
Temperature Resistance
Temperature resistance is the maximum temperature that the material or product can withstand for a period of time. The temperatures listed should be considered as guidelines for an operating temperature of about 30 minutes. Typically, the material can withstand much longer times at temperatures about 20°C lower and can withstand much higher temperatures for short, intermittent times.
54 ˚C
Chemical Properties
Melting Point
86
Other Properties
Storage Temperature
16 - 27 °C

Additional Information

Technical properties

As-supplied / before-processing properties

Values are typical and not specifications.

PropertyValueUnitMethod / condition
ColorTan-Solid adhesive
Density0.95g/cm^3Solid adhesive
Recommended application temperature177 to 196deg CHot-melt application
Viscosity2,875cP191 deg C; Brookfield Thermocel #27 at 10 rpm
Open time50s3.2 mm bead on nonmetallic substrate at 24 deg C
Delivery time35s25 x 76 mm PG cartridge
Technical properties

After-processing / final-state properties

Values are typical and not specifications.

PropertyValueUnitMethod / condition
Heat resistance54deg CHighest temperature supporting a 14 kPa dead load
Ball and ring melt point86deg CASTM E28-67
Overlap shear strength375psiDouglas fir bonded to Douglas fir
Peel strength13piwFlexible canvas bonded to Douglas fir

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