LOCTITE ECCOBOND UF 3578

Harmonization Code : 3907300090 | Polyacetals, other polyethers and epoxide resins, in primary forms; polycarbonates, alkyd resins, polyallyl esters and other polyesters, in primary forms

Main features

Fast heat-cure adhesive designed for underfill and fixture applications
Thixotropic and fluorescent for controlled flow and optical inspection
Reflow-compatible for SMT processes

Product Description

LOCTITE® ECCOBOND UF 3578 is a one-component, heat-curable epoxy underfill designed to provide mechanical reinforcement and encapsulation in surface mount PCB assemblies. Its thixotropic, fluorescent formulation makes it especially well-suited for applications involving capacitors, resistors, connectors, and WLCSPs, where precise flow control and post-process inspection are critical.

This adhesive offers fast curing at 120 °C in just 10 minutes and is fully compatible with solder reflow processes, eliminating the need for separate curing stages. LOCTITE® ECCOBOND UF 3578 ensures excellent mechanical strength and thermal protection while maintaining ease of use.

Applications

Underfill for WLCSP, capacitors, resistors, and connectors
Reinforcement and protection in SMT and PCB assembly
Electronics requiring fast cure and reflow-process compatibility
Optical inspection environments (fluorescent visibility)

Product Family
UF3578

1. Select Package Type

30cc Syringe

Catalog Product

Unlike other products we offer, the products listed on this page cannot currently be ordered directly from the website.

Shortest leadtime

Shipping in 8 - 12 weeks

Contact for Pricing

Packaging

TDS, SDS & Technical documents

Specifications
Additional Information

Technical Specifications

General Properties

Color

Color
The color

Black

Density (g)

1.4 g/cm3

Shelf Life Shelf Life Shelf life is the amount of time after manufacturing that a product is guaranteed to retain its properties. It differs vastly per product and it is based on temperature and storage conditions. The properties can be guaranteed for the temperature and time range indicated on the TDS since those are the ones tested to be the best for the product.
Shelf Life @ 5°C	183 days

Physical Properties

Thixotropic index

Thixotropic index
Thixotropic Index is a ratio of a material s viscosity at two different speeds in Ambient temperature, generally different by a factor of ten.

A thixotropic material s viscosity will decrease as agitation or pressure is increased. It indicates the capability of a material to hold its shape. Mayonnaise is a great example of this. It holds its shape very well, but when a shear stress is applied, the material easily spreads.

It helps in choosing a material in accordance to the application, dispense method and viscosity of a material.

3.9

Viscosity

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

55,000 mPa.s

Thermal Properties

Coefficient of Thermal Expansion (CTE) Coefficient of Thermal Expansion (CTE) CTE (Coefficient of thermal expansion) is a material property that is indicative of the extent to which a material expands with a change in temperature. This can be a change in length, area or volume, depending on the material. Knowing the CTE of the layers is helpful in analyzing stresses that might occur when a system consists of an adhesive plus some other solid component.
Coefficient of Thermal Expansion (CTE) , α1 Coefficient of Thermal Expansion (CTE) , α1 CTE α1 (alpha 1) is the slope of the Coefficient of thermal expansion in a temperature range below the Glass transition temperature (Tg). It explains how much a material will expand until it reaches Tg.	39 ppm/°C
Coefficient of Thermal Expansion (CTE), α2 Coefficient of Thermal Expansion (CTE), α2 CTE α2 (alpha 2) is the slope of the Coefficient of thermal expansion in a temperature range above the Glass transition temperature (Tg). It explains the extent to which a material will expand after it passes Tg.	138 ppm/°C

Glass Transition Temperature (Tg)

Glass Transition Temperature (Tg)
The glass transition temperature for organic adhesives is a temperature region where the polymers change from glassy and brittle to soft and rubbery. Increasing the temperature further continues the softening process as the viscosity drops too. Temperatures between the glass transition temperature and below the decomposition point of the adhesive are the best region for bonding.

The glass-transition temperature Tg of a material characterizes the range of temperatures over which this glass transition occurs.

121 °C

Additional Information

Cure Profile

10 minutes at 120 °C (standard cure)

*Compatible with standard solder reflow processes

Thawing Instructions

Allow container to reach room temperature before use.
After removing from the freezer, set the syringes to standvertically while thawing.
Thaw time typically 1 hour for 30/55cc syringe .
Consult handling guide for more information.
DO NOT open the container before contents reach 25 °Ctemperature. Any moisture that collects on the thawed containershould be removed prior to opening the container.
DO NOT re-freeze. Once thawed to 25 °C, the adhesive shouldnot be re-frozen.

Storage & Handling