LOCTITE EA 3981

Harmonization Code : 5906100000 | Adhesive tape of a width not exceeding 20cm

LOCTITE EA 3981

Main features

  • One-Component No-Mix Adhesive
  • Heat Cure as Low as 100 deg C
  • Disposable-Needle/Syringe/Lancet Cannula Bonding

Product Description

LOCTITE® EA 3981 is a one-component, heat-cure epoxy adhesive developed for assembling disposable medical devices. The translucent, slightly amber liquid requires no mixing and fluoresces under ultraviolet light to support inspection during production. It cures at temperatures as low as 100°C and bonds plastics, metals, and glass. The product is specifically designed for bonding stainless steel cannulae into hubs, syringes, and lancets used in needle assemblies. Its combination of rapid thermal curing, adhesion across multiple substrate types, and resistance to environmental exposure supports high-speed medical-device assembly processes.

Key features

  • One-component epoxy: Requires no mixing before application, simplifying material preparation and dispensing.
  • Rapid heat cure: Cures at temperatures as low as 100°C, with documented cure schedules for production processing.
  • UV fluorescence: Produces a positive response under ultraviolet light to support adhesive-presence inspection.

Applications / Suitable for

  • Bonding stainless steel cannulae into plastic hubs
  • Needle, syringe, and lancet assemblies
  • Assembly of disposable medical devices
  • Bonding plastics, metals, and glass
Product Family

LOCTITE EA 3981

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TDS, SDS & Technical Documents

Technical Specifications

General Properties
Component System
Describes the number of components that must be supplied, mixed, or activated before application or cure.
One part
Specific Gravity
Specific gravity (SG) is the ratio of the density of a substance to the density of a reference substance; equivalently, it is the ratio of the mass of a substance to the mass of a reference substance for the same given volume. For liquids, the reference substance is almost always water (1), while for gases, it is air (1.18) at room temperature. Specific gravity is unitless.
1.14
Physical Properties
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
4,000–6,000 mPa.s
Mechanical Properties
Elongation
Elongation is the process of lengthening something. It is a percentage that measures the initial, unstressed, length compared to the length of the material right before it breaks. It is commonly referred to as Ultimate Elongation or Tensile Elongation at break.
2.98 %
Chemical Properties
Water Absorption
1.8 %

Additional Information

Technical properties

As-supplied / before-processing properties

Typical properties of the adhesive before heat curing.

Property Value Unit Method / condition
Technology Epoxy — As supplied
Components One component — Requires no mixing
Appearance Translucent, slightly amber liquid — Uncured material
Fluorescence Positive — Under UV light
Specific gravity 1.14 — At 25°C
Viscosity 4,000–6,000 mPa·s (cP) Brookfield SSA-RVT, 25°C; spindle 14, 50 rpm
Optimal storage temperature 2–8 °C Store unopened in a dry location

After-processing / final-state properties

Typical properties of the heat-cured adhesive under the stated cure and test conditions.

Property Value Unit Method / condition
Shore hardness ≥70 Durometer D ISO 868; cured 30 minutes at 120°C
Glass transition temperature 56 °C ASTM E 228; cured 30 minutes at 125°C
Coefficient of thermal expansion, below Tg 62 × 10-6 K-1 ISO 11359-2; cured 30 minutes at 125°C
Coefficient of thermal expansion, above Tg 193 × 10-6 K-1 ISO 11359-2; cured 30 minutes at 125°C
Elongation at break 2.98 % ISO 527-3; cured 30 minutes at 125°C
Tensile strength 62 N/mm² ISO 527-3; cured 30 minutes at 125°C; 8,970 psi
Tensile modulus 2,383 N/mm² ISO 527-3; cured 30 minutes at 125°C; 345,500 psi
Lap shear strength ≥13.8 N/mm² Etched aluminum, 0.125 mm gap; cured 30 minutes at 120°C; ≥2,000 psi

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