ADHESIVES&SEALANTS

INDUSTRY

Hybrid Adhesive Formulations | Renewable Isocyanate Blocking Agent | OEM Testing Requirements

Serving the Global Formulator, Manufacturer & End User

AUTOMOTIVEASSEMBLY

October 2020
Volume 27, Issue 10
www.adhesivesmag.com

TABLE OF
CONTENTSADHESIVES&SEALANTS

INDUSTRYOCTOBER 2020 | VOLUME 27, ISSUE 10

20

Hybrid Adhesive Formulations | Renewable Isocyanate Blocking Agent | OEM Testing Requirements

ADHESIVES&SEALANTS

INDUSTRY

Adhesives in Automotive Assembly
Advanced sealants and adhesives in vehicle assembly effectively and safely
address key applications that have traditionally employed mechanicalfasteners while adding design freedom to today’s modern vehicles.

Serving the Global Formulator, Manufacturer & End User#assembly #automotive #electronics

30

Industry Assembles Virtually at The ASSEMBLY Show
The ASSEMBLY Show is virtual this year—early access began inAugust, the event is being held October 27-28, and on-demand login
opportunities will last through June 2021. #events #assembly #bonding

AUTOMOTIVEASSEMBLY

32

Put Some Moxie in Your Epoxy
The addition of a low-viscosity, blocked polyurethane prepolymer improves
the strength and reduces the cure time of epoxy adhesives.
#epoxies #polyurethanes #hybridadhesives

40

Renewable Alternative: Cashew Nutshell Liquid-Based
Isocyanate Blocking Agent
A high-purity cardanol derived from renewable cashew nutshell liquid
offers chemical features that can be successfully used in epoxy andpolyurethane adhesives and sealants. #biobased #epoxies #polyurethanes

50

Going Above and Beyond OEM Testing Requirements
The best practice in testing procedures involves incorporating additional
quality control and testing standards beyond those required by OEM
partners. #testing #qualitycontrol #surfacetreatment

53

Performance Testing of Hydrophilic Coatings on Medical Devices
It is vital to choose the right testing methods to create certainty andpredictability in the manufacture and use of hydrophilic coatings for
implantable medical devices. #medical #coatings #testing4

ASI • October 2020 • www.adhesivesmag.com

October 2020
Volume 27, Issue 10
www.adhesivesmag.com

On the cover:
Image courtesy of Sika Automotive.

COLUMNS
From the Editor .......................8
M&A Corner ..........................18
Strategic Solutions ................46
Ask Dr. Dave .........................61

DEPARTMENTS
Company News ......................10
People in the News ................13
International Calendar ............15
Services Marketplace .............58
Classifieds ............................59
What's New ...........................60
Ad Index ...............................62

FEATURE
ARTICLE#assembly #automotive #electronics

Polyurethane adhesive beadapplied on backlight waiting
installation to vehicle inassembly line.

Adhesives in Automotive Assembly
Advanced sealants and adhesives in vehicle assembly effectively and safely address
key applications that have traditionally employed mechanical fasteners while adding
design freedom to today’s modern vehicles.

By Greg Moran, Vice President
and Head Global
Automotive Marketing,Sika Automotive

20

T

ransportation has evolved tremendously over the last century.
From horse and buggy to steam power, the internal combustion
engine, multi-speed powertrains, and the latest push forhybrids and electrification—the way things move has changed
tremendously. Not only have power systems evolved, so too have theconstruction and finishes of vehicles, including steel body enclosuresand the addition of windscreens, plush interiors, and electronic systems.

ASI • October 2020 • www.adhesivesmag.com

FEATURE ARTICLE
Adhesives have also evolved over the last 100-plus
years, in both formulations and applications in
vehicle assembly. Advanced sealants and adhesives
in vehicle assembly effectively and safely address
key applications that have traditionally employedmechanical fasteners (e.g., rivets, welds, screws,
and clinches) while adding design freedom totoday’s modern vehicles.
The use of adhesives is by no means new, but theirgrowing use enables design trends that even 10 years
ago were improbable. Driving the growth of adhesive
use are global megatrends in the ever-changing worldof assembling vehicles (see Table 1, p. 22).
As illustrated in Figure 1, it is quite easy to seethat occupants in today’s advanced vehicles are
surrounded by adhesives. And while they are neverseen, adhesives are critical to vehicle performance,
aesthetics, and comfort.
For adhesive suppliers and users, the selectionof products and chemistries is based on multiple

factors, including the materials to be joined, joint
design assembly method (automated or manual,room temperature or heated dispense), and curing
process (heated or cold curing). Further, theperformance requirements of the adhesive/substrateinterface (i.e., the joint) must be determined. Is thefunction bonding or sealing, rigid or flexible, crashor non-crash, or general assembly? Performancerequirements must also be accounted for, whether
the adhesive is located in the body structuralassembly or in visible panels and hang-on parts
where class A surfaces exist that cannot exhibit
bond line read through (BLRT).
Today’s world of mixed materials brings additional
considerations with regard to delta/alpha (/).
Different materials expand and contract atdifferent rates (e.g., aluminum, steel, or carbon
fiber). Adhesives can and do play a crucial role incompensating for materials’ different expansion
coefficients and, in effect, can serve as the interface
allowing for these differentials. Figure 2 (p. 22)shows a basic breakdown illustrating chemistries

Figure 1. Typical automotive sealant and adhesive applications.

www.adhesivesmag.com • October 2020 • ASI

21

FEATURE ARTICLE
Table 1. Megatrends driving adhesive usage.
Global Megatrend

Effects

Solutions

Increasing global CO2 regulations and mileage
requirements

Weight reduction; lightweight design approaches
introduce mixed material bonding (multiple steels,
aluminum, carbon fiber, advanced plastics)

Adhesives as joining agents with or without
mechanical fixations

Lightweighting through metal reduction activities invehicle body structure and body panels

Reduced vehicle dynamics and safety

Structural adhesive bonding of body assembly andaddition of structural inserts at critical body nodes tomaintain functions; reinforcements of thinner panel
skins

Increasing global crash safety requirements in all
regions

Need for enhanced design of vehicle body
constructionMore use of structural crash adhesives in strategic
locations along with mechanical and lightweight
structural inserts

Growing production and mainstream penetration ofelectric vehicles in all regions through 2030

Traditional mechanical drivetrain components
replaced with batteries/packs, chargers, controllers,and drive motors

E-vehicles benefit from mixed material construction
enabling lightweighting for range enhancement;
e-components require advanced functional adhesives
for performance, thermal conductivity, de-bondon demand, heat-resistant potting; unique acoustic
treatments

Global regulations and sustainability initiatives

Regional agencies’ (REACH, TSCA, etc.) positions on
chemical use

Adhesives suppliers already self-policing foralternative formulation materials while maintaining
high-performance; low monomeric content and MDIfree formulations for classification-free alternatives

and performance parameters with overlaps
depending on performance requirements.

Figure 2. A sweet spot requirement for mixed materials.

Adhesive chemistries include epoxies,
polyurethanes, methylmethacrylates, rubber-based
anti-flutters, PVC, butyls, bitumens, thermoplastics,
and in-component manufacturing silicones. Products
are chemically cured (i.e., two-component A/B witha base and an activator base), “boosted” to ensure
faster rates of cure (polyurethanes), or cured solely
by heat or moisture condensation. Adhesives arealso rated with modulus-hardness and elongationflexibility.
Adhesive applications can be organized by theareas where the majority of assembly operations are
performed: body shop, paint shop, and trim shop. In
addition, multiple sub-assemblies from component
suppliers add in at various stations in the process.
In the Body Shop
Widely used in vehicle body shop (body in white,or BIW) assembly applications—and regularly
applied in concert with mechanical fixation—hotcured epoxy technologies are the product of choice.
This also holds true for the hang-on parts such as
22

ASI • October 2020 • www.adhesivesmag.com

doors, hoods, and liftgates. A variety of productperformance ranges are available that are specific to
the required applications of sealing, semi-structural,
structural, or crash. Products are specification
driven, and OEMs typically have similar but slightly
differing requirements.

FEATURE ARTICLE
Injection-molded fiber reinforced plastic (FRP)
inserts designed to the contours of cavity placement
can be secured either by pre-molded epoxy
coatings or body shop adhesives for even higher
performance. As mass is removed, structural inserts
compensate for the differentials. The inserts areplaced strategically through modeling performanceand are added to strategic nodes to add rigidity
and improve NVH and/or crash performance whererequired. Typical crash applications include frontal
crash, side crash, or roof crush to prevent impact
intrusion to the passenger compartment. This
technology approach allows for lightweighting efforts
to be achieved while maintaining or even enhancing
structural integrity and vehicle dynamics.
Typical application of epoxy body shop adhesive duringassembly process.

In addition, rubber-based anti-flutter adhesives bondthe larger panels such as roof bows to roof skins andhoods to frames while providing firm but flexible
joining to eliminate vibration. BIW adhesives must
be corrosion tested and qualified for applications
through rigorous tests and test methods, including
crash testing.
Adhesives also function to prevent galvanic corrosion
between dissimilar substrates. Application is doneat component suppliers for hang-on parts and in
the production line for BIW completion. Epoxy
and rubber-based products cure in the bake ovens
following assembly and e-coat.
Adhesives also add physical and audible comfort
to interiors by improving vehicle dynamics andmanaging acoustic performance behind the scenes.
Structural adhesives stiffen the body structureby joining the various components of the BIW.
Additional opportunities to add stiffness and safety
are available through the selective use of lightweightgeometric structural reinforcements as alternatives
to heavier metal reinforcement.
24

ASI • October 2020 • www.adhesivesmag.com

To further address comfort, highly engineered“baffle” products—combinations of Nylon andthermoplastic materials provided as engineeredparts or extruded tapes—are added to vehicle body
cavities during assembly to block airborne noise
paths in the pillars of the vehicle, along the beltline,
and throughout the sills for watertight applications.
The thermoplastic material expands in the bakeovens to seal the cavities. To eliminate structureborne noise, “adhesives” include applications ofconstrained layer dampers in butyl and bitumen,
bitumen damping patches, melt sheets, or liquidapplied coatings known as LASD. Between baffle
and damping, applications can be optimized throughfull vehicle testing in acoustic labs for highly tuned
combinations and optimal efficiencies.
In the Trim Shop
Direct glazing of glass (e.g., windshields, sidelights,
and decorative glass) is also accomplished in trim
typically using one-component polyurethane-based
products. Component assemblies added to thevehicle in the trim shop also benefit from adhesives.

The move toward the use of more and larger glass
elements in vehicles such as sunroofs and wideopen panoramic roofs (WOPR), coupled with new

FEATURE ARTICLE
Anti-flutter adhesives are used toprovide flexible bonds for vehicle
panels subject to vibration, as
shown here with the roof panel tothe roof bow.

combinations of plastics usedin their housings, has led tothe development of specificchemistries that enable reliable
adhesion. These are fed to theline typically as assemblies,
but are installed in trim. New
high-performing headlamps, taillamps, spoilers, antennas, andautomated sensing door handles
also join the vehicle body here,
and all benefit from advanced
adhesives use, typically at theTier 1 component manufacturers.
Adhesives also enable theevolution of the visible vehicle
interior, enhancing the personalenvironment while answering thechallenges of mixed materials(e.g., PVC, TPO, and ABS tovinyl, plastic, and leather skins),
affording high-end possibilities
not only for luxury vehicles but
also providing plushness to all
vehicle levels. Thermoplastic
coatings, reactive urethanes, andwater-based coating products
are used to laminate door skins,
armrests, headliners, consoles,
load floors, and steering wheels
with materials to add the soft
touch to the cabin environment.
Further, spray adhesives usedin flocking applications add thesoft surfaces to glove box andconsole compartments, as well as

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www.adhesivesmag.com • October 2020 • ASI

25

FEATURE ARTICLE
Today’s sophisticated headlamps
require the use of equallysophisticated adhesives to enablelong-term performance and fast TAKT
time testing at the line.

the various seals seen in typicalopenings in the vehicle (e.g.,
doors and liftgates).
Automobiles as Computing
Platforms
When we look back several
decades, a notable evolution has
been the conversion of vehicles tocomputing platforms with highperforming systems. Accessory
systems such as active cruise
control, lane departure, back-up
cameras, automated park systems,
automated braking, traction
control, vehicle guidance, infotainment, wirelessnetworking, satellite guidance, and heated accessories
such as seats and steering wheels have added moreadhesive use to vehicles.

Most prominent in these categories are the variety
of system ECUs, controllers, harnesses, sensors,and in-dash and overhead displays. We take thesesystems for granted, but their performance is enabledthrough encapsulation, potting, bonding, and sealing
processes for long-term durability and performance.
Typical chemistries here are two-part polyurethane,
epoxies, and two-part silicone chemistries.
Electrification Evolution or Revolution?
The most current megatrend driving automobiles
is the electrification of our industry, and only
history will decide the correct terminology. While
headlines drive the news, the wave of conversion
is actively underway. The remaining question is
only how consumers will embrace the shift. With
electrification, the groundwork is also solidified forthe next megatrend.
26

ASI • October 2020 • www.adhesivesmag.com

New vehicles in this class rely on advanced bodylightweighting for extended range capability and tocompensate for the weight of added componentry.
Body structures must accommodate new systems,
including batteries, battery packs, electric drive
motors, on-board chargers, and a new seriesof electronics. In addition, while different, theelimination of traditional drivetrain components also
simplifies assembly.
Two major paths of thought have emerged withmany design approaches: offering traditional vehicle
types that offer electric variants including hybrid
and full electric versions, or specially designed bodyarchitecture specific to the electric-only versions.
Further vision in this direction also potentially includes
a sled and a top-hat variant that allows multiple
vehicle models with a common drivetrain/drive module.
Within all approaches, we can expect that adhesives willremain a primary technology for enabling the migration.
Indeed, opportunities exist for expanded adhesive
usage, as battery packs require both heating and cooling

FEATURE ARTICLE
Typical constrained layer damper for
structure-borne noise abatement.

systems to operate at maximum
performance; heat is both an enemy
and an ally to peak functionality,
depending on the geographic
locations of vehicle operation. In
addition, added protection will be
required for battery packs in case ofcollision events.
There is no doubt, regardless ofthe design approaches taken,
that functional adhesives provide
unique performance characteristics,
including faster cure, thermal
conductivity, and heat insulation,
as well as fire-rated adhesives andcoatings and selective reinforcement techniques forbattery pack safety. All of these factors will enable
the design choices made.
Future Growth
What does the future hold for automotive adhesive
usage? Growth. From adhesive manufacturers’ orapplicators’ perspectives, considerations continue tobe driven by global megatrends and include:• More value-add approaches for assembly using
adhesives in automated applications for reduction/
elimination of mechanical fixation and labor costs• Novel product chemistries combining the benefitsof multiple chemistries in use today to newbaseline formulations with combined benefits• Continued and increased use of mixed materials
require consideration of joining methods that
accommodate unique / challenges and theelimination of BLRT on Class A surfaces• Cure-on-demand technologies, as well as allowance forfast fixation similar to spot welding prior to full cure
• De-bond on demand for serviceability, particularly
in electric vehicle componentry where service
must be performed28

ASI • October 2020 • www.adhesivesmag.com• New approaches to acoustic solutions in electricvehicles due to the absence of traditional engine
and transmission noise and new frequencies innoise transmission• Lower bake temperatures experienced by design
where heat does not penetrate metals fully, or
through sustainability initiatives by manufacturers(utility savings)• Continued regulations regarding chemical
ingredients/formulations and regional moves
toward “odor-free” adhesive products (e.g.,
Europe and China)• Enhanced use of modeling adhesive performancein “virtual” analysis to predict performance andfailure in conjunction with or prior to prototype
build levels
There is no doubt that adhesive chemistries’ use andversatility will continue to flourish in enabling theresults of the megatrends that continually change ourindustry. The global adhesives supplier base is readyto meet the next big design challenges. ASI
For more information, contact the author at (248) 577-1024 or
moran.greg@us.sika.com, or visit https://automotive.sika.com.