JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 98

thermoset

Reformable epoxy adhesive film

L&L Products introduces L-F610, an innovative resin film combining
the adhesion and mechanical benefits of an epoxy with the processing speed of a thermoplastic. This amorphous material exhibits excellent adhesion to a variety of substrates while retaining the handling
ease and versatility of a thermoplastic. The resin can be used in a
variety of forms, including as an adhesive or as the matrix in a composite laminate. Due to its affinity with epoxy thermoset resins, it is
a material of choice for combining with thermoset composites based
on epoxy.

uture composite manufacturing
will require simplified processes
and a reduction of manufacturing
cycle times. Over the past few years, L&L
Products has focused on creating innovations for the composite industry based on
these needs. In this regard, thermoplastics
are a material of choice, and interest in this
class of materials is growing. One of L&L's
newest innovations is a reformable epoxy
adhesive film. Designated L-F610, this film
combines the adhesion and mechanical
properties of an epoxy with the processing
ease of a thermoplastic. L-F610 will facilitate new opportunities for the manufacture
of composite parts, panels and laminates.

combined with an expected high affinity to
epoxy and metallic substrates, can lead to
interesting properties for some composite
and adhesive applications.
The first application developed from this
resin is the L-F610 reformable epoxy
adhesive film. This film is obtained by processing the L-TE01 resin by calendering
extrusion. The result is a clear, dry-to-thetouch film - making it easy to handle. The
film acts as a hot melt film adhesive, bonding substrates together by heating the resin
and allowing the assembly to cool down.
Some lap shear specimens were produced

By
Laurent Meistermann - R&D Manager,
Brandon Madaus - Materials Development
Technical Specialist
L&L Products

to evaluate the strength of such assemblies.
The resulting values (see Figure 1) show
impressively high lap shear strength for
a thermoplastic adhesive. Without any
specific surface treatments, values as high
as 15MPa on galvanized steel, and 13Mpa
on sandblasted aluminium and cleaned
epoxy GF composite, can be obtained.
With a chemical etching treatment on the
aluminium, the lap shear strength can reach
18MPa. Despite the resin's relatively low
glass transition temperature (80°C), the
assembly still exhibits a strength as high
as 14MPa at 80°C and excellent strength
properties at low temperatures (see Figure

Properties
The L-F610 film is based on the recently
developed L-TE01 resin, an amorphous
thermoplastic resin obtained by linear
polymerization of epoxy monomers. The
tensile results obtained on injectionmoulded samples from the pure resin show
a modulus of 3GPa, a tensile strength of
60MPa and an elongation at break of 40%.
This high strength and outstanding elongation at break for an epoxy-based product,

Fig. 1: L-F610 lap shear values at room temperature and evolution with testing temperature on aluminium
(bond line 0.25mm)

98 jec composites magazine / No95 March 2015

JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015