Henkel s Solutions for Touch Panels & Displays

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Henkel offers complete engineering services for projects demanding

expertise and support beyond the limits of standard technical

services. Our engineers provide the following value-added services.

• On-site engineering assistance and consultation

• Joint product development programs

• Contract lab services and testing

• Prototype testing

• Custom formulations

Engineering Services

Achieving more with less

Our commitment to leadership in sustainability is deeply embedded in our values.

With our revised Sustainability Strategy for 2030, we are building on our strong

track record. At the same time, we are aiming to address one of the central future

challenges: to decouple growth from resource consumption. At the heart of this

strategy is therefore the simple, yet challenging, ambition: to achieve more with

less. It aims to create more value for our customers, consumers, communities and

the company alike, while simultaneously reducing the environmental footprint.

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www.Loctite.com/loca

your totaL SoLution providEr for adhESivES,

SEaLantS and functionaL coatingS

Through close customer partnership,

industry know-how and engineering

support, we enable innovative design

for handheld devices and displays

customer

intimacy

Through close collaboration and

intimate knowledge of customer

applications and processes, Henkel

creates exciting solutions that

enable innovation.

Engineering

Support

With unsurpassed development,

engineering and field support –

Henkel provides the expertise to

empower customers to improve

quality, efficiency and innovation.

global

capabilities

We are the global

technology leader with an

extensive network to support

the customers’ value stream.

innovation

Leader

As the innovation leader

in sealing, bonding and coating

– Henkel delivers solutions to

meet fast design changes and

developmental challenges.

design

partnership

Our experienced team of

engineers provide

documented design and

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LOCTITE

Liquid Optically Clear

Adhesives (LOCAs)

The primary function of an

optically clear adhesive in a

display is to eliminate reflection

loss and/or glare caused by air

gaps between touch panel layers.

Today the majority of touch

panels are small (< 4’’), resistive

and capacitive touch panels that

are used in mobile devices. These

small touch panels are normally

assembled using an optically clear

double sided tape.

But the touch panel market is

rapidly changing. As the average

touch panel size increases

with tablets and monitors

becoming more common and the

performance requirements of

optically clear adhesives increases,

table 1

illustrates the clear

performance and manufacturing

advantages of LOCA over OCA

tape which will drive the rapid

adoption of LOCA over the next

several years.

Performance Comparison: LOCA vs. OCA Tape

Benefits of LOCA

In mobile devices, laptops, tablets, monitors and television sets, the majority of the designs

today do not have a touch panel and have at least one air gap between the cover glass and

the LCD module. Over the next several years, the touch interface will become ubiquitous in

displays and manufacturers will strive to improve the customer experience by:

• improving the viewing experience

— with LOCA and A / R glass you can increase contrast ratio by 400% in sunlight. Henkel has

minimized loss due to reflection by matching the refractive index (1.5) to glass and PMMA.

• increasing display ruggedness

— for large gaps up to 1 mm, you can increase the falling ball impact resistance by up to 3X.

• Extending battery life

— by reducing light loss due to reflection, the end user can get a superior viewing

experience with less power consumption greatly extending battery life.

• Extending display product life

— LOCA makes a display more durable to heat, moisture and temperature cycling.

• Enabling thinner designs

— LOCA will absorb the impact of a given load when compared to an assembly with an air

gap, allowing for thinner designs while protecting the display surface.

taBLE 1

Loca

oca tape

Gap Filling

(Edge of Ink Coating) Excellent General / poor

Repairability Repair can be done at pre-curing

stage Cannot be done

Assembly Process Can be fully automated Semi-automated

Adhesion / Reliability High Low

Large Panel More suitable Less suitable

Inventory Size independent Various pre die cut needed

Surface Preparation Less demanding More demanding

Equipment Adhesive application, assembly at

ambient or vacuum, pre-cure and full cure

Roller lamination and autoclave

EnhancE diSpLayS with SupErior pErformancE

and EaSy procESSaBiLity

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Typical LOCA Applications

cover Lens

touch panel Sensor

Loca

direct Bonding

display module

Loca

cover Lens Bonding

dam Loca

SEE pagE 6 SEE pagE 7 SEE pagE 11

Loca

Glass or PMMA with ink

Typical gaps are ~100 - 150 um

Typical gaps are ~200 - 300 um

Used to control the flow of the LOCA

Typically open or closed cell LCD or OLED

Typically glass or films with a flexible

printed circuit connector

cover Lens

cover Lens Bonding

touch panel Sensor

direct Bonding

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Cover Lens Bonding

Introduction

Bonding the cover lens to the touch panel sensor is generally

straight forward when both are made of glass. Normally a

fast curing, high strength, refractive index matched LOCA is

desired and many are available which can meet the needs of

the application. In this case, the key differentiators are often

related to the manufacturing consideration such as the LOCA

application time, cure time and first pass manufacturing yield.

When using a plastic cover lens or film touch panel sensor, the

plastic is more difficult to adhere to than the glass and it has

different coefficients of thermal expansion than the glass. This

make the application more challenging and a very high strength

LOCA such as LOCTITE

®

_{3193HS is typically required.}

common materials

• Glass or PMMA

• ITO coated glass

• ITO coated PET films

typical gap

• 100 - 150 micron

Key performance requirements

• Low viscosity

• High durometer / modulus

• High adhesion to glass & plastic

• > 99% transmission

• < 1% haze

• < 1 yellowness (b*)

typical reliability requirements

• HT: 80 °C for 1,000 hours

• HTHH: 60 °C / 90% RH for

500 hours

• TC: -40 °C / 80 °C for 500 cycles

• UV: UV aging for 500 hours

recommended adhesives

• High performance

,

second generation – LOCTITE

®

₃₁₉₄

• General purpose

,

first generation – LOCTITE

®

₃₁₉₅

• PMMA

cover lenses

– LOCTITE

®

_3193HS

• Film

touch panel sensors

– LOCTITE

®

_3193HS

• Secondary heat cure

– LOCTITE

®

₃₁₉₂

• Secondary moisture cure

– LOCTITE

®

₅₁₉₂

characteristics LoctitE® 3192 LoctitE® 3193hS LoctitE® 3194 LoctitE® 3195 LoctitE® 3800 LoctitE® 5192

Chemistry Acrylic Acrylic Acrylic Acrylic Acrylic Silicone

Curing Method 1 UV / Heat

(80 ºC / 1 hour) UV UV UV UV UV / Moisture

Full Cure Energy (mJ/cm2₎

(@ 100 mW/cm2_UVA, MPMA UV Source) 4,000 3,000 2,000 3,000 2,000 5,000 Viscosity (cP @ 25 °C) 4,000 - _5,000 4,600 - _6,800 1,800 - _2,800 3,000 - _4,000 2,500 - _3,500 3,500 - _5,500 Hardness (Shore 00) 56 65 60 22 45 65 Shear Modulus-G' (Kpa, Rheometer) 83 8,830 78 42 100 70 Elongation 100% 300% 150% 250% 1000% 100% Refractive Index 1.49 1.51 1.51 1.51 1.47 1.41 Transmittance (%) (average 380 - 780 nm) > 99 > 99 > 99 > 99 > 99 > 99 Volume Shrinkage (%) 3.00 3.10 3.00 1.56 3.00 0.54

Adhesion - Glass to Glass,

100 μm (MPa) 1.1 7.6 5.0 1.2 1.6 0.4

Adhesion - Glass to Polarizer (Nitto Denko AG

254 μm gap) (MPa) - - - - 0.86 0.59 Adhesion - Glass to Polarizer (LG Bare 254 μm gap) (MPa) - - - - 0.85 0.63 Yellowness (b*) 0.30 0.10 0.01 0.41 0.10 0.19 Haze (%) < 0.20 0.09 0.12 < 0.20 0.11 0.04 Dielectric Constant (1 MHz) 4.69 3.24 2.83 2.45 3.93 3.10

1. _{UVV curable for all products except LOCTITE}®_{5192 & LOCTITE}®_{5192DM, while it needs to be tested according to actual} conditions.

Selector Guide

Cover Lens

LOCA

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Introduction

As the end users expectation of the displays appearance and

durability increases, direct bonding is becoming more and

more common. Direct bonding is much more challenging than

cover lens bonding for a variety of reasons. First, LOCA for

direct bonding must prevent MURA issue while maintaining

high adhesion strength. Second, the polarizer film that is the

top layer of the LCD display modules is harder to bond than

glass. Lastly, due to end devices’ designs, there can inevitably

be shadow areas between LCD and touch or cover lens. Henkel

has developed a variety of direct bonding adhesives that were

specifically formulated for this application and are used in mass

production applications today.

common materials

• ITO coated glass

• Glass or PMMA

• Polarizer film

typical gaps

• ~200 - 300 micron

Key performance requirements

• Low viscosity

• Low durometer / modulus

• Low shrinkage

• High adhesion to glass & plastic

• > 99% transmission

• < 1% haze

• < 1 yellowness (b*)

typical reliability requirements

• HT: 80 °C for 1,000 hours

• HTHH: 60 °C / 90% RH for

500 hours

• TC: -40 °C / 80 °C for 500 cycles

• UV: UV aging for 500 hours

recommended adhesives

• Ultra low MURA

,

second generation

– LOCTITE

®

_{3191, LOCTITE}

®

_{3198 and}

LOCTITE

®

₃₁₉₉

• General purpose

,

first generation – LOCTITE

®

₃₁₉₆

• Ultra fast curing

– LOCTITE

®

_{3191 and LOCTITE}

®

₃₁₉₉

• Secondary moisture cure

– LOCTITE

®

₅₁₉₂

• Excellent side cure

– @ 365 nm LED: LOCTITE

®

₃₁₉₁

and LOCTITE

®

₃₁₉₆

– @ 405 nm LED: LOCTITE

®

_3191,

LOCTITE

®

_{3196 and LOCTITE}

®

₃₁₉₉

characteristics LoctitE® 3191 LoctitE® 3196 LoctitE® 3198 LoctitE® 3199 LoctitE® 5191 LoctitE® 5192 LoctitE® 5193 LoctitE® 3196pr

Chemistry Acrylic Acrylic Acrylic Acrylic Silicone Silicone Silicone Acrylic

Curing Method 1

UV UV UV UV UV UV / _Moisture UV / _Moisture UV / 7389 _primer

Full Cure Energy (mJ/ cm2_{) (@ 100 mW/cm}2

UVA, MPMA UV Source) 1,000 3,000 2,000 1,000

1,000 - 3,000 5,000 1,000 - 3,000 3,500 Viscosity (cP @ 25 °C) 1,800 - _2,800 3,200 - _4,200 3,600 - _5,200 _2,8001,800 - 2,200 - _3,200 3,500 - _5,500 2,400 - _3,400 3,200 - _4,200 Hardness (Shore 00) 5 11 5 8 68 65 70 3 Shear Modulus-G' (Kpa, Rheometer) 10 17 13 14 119 - 208 70 114 - 205 16 Elongation 300% 300% 700% 400% 130% 100% 120% 200% Refractive Index 1.47 1.51 1.52 1.47 1.41 1.41 1.41 1.51 Transmittance (%) (average 380 - 780 nm) > 99 > 99 > 99 > 99 99.61 > 99 99.7 > 99 Volume Shrinkage (%) 1.60 1.39 1.10 1.60 < 0.50 0.54 < 0.70 1.26 Adhesion - Glass to Glass, 100 μm (MPa) 0.7 1.0 0.7 0.6 0.3 0.4 0.5 0.9 Adhesion - Glass to Polarizer (Nitto Denko

AG 254 μm gap) (MPa) 0.20 0.37 0.29 0.27 0.17 0.59 0.23 0.33 Adhesion - Glass to Polarizer (LG Bare 254 μm gap) (MPa) 0.19 0.21 0.24 0.25 0.23 0.63 0.23 0.20 Yellowness (b*) 0.05 0.18 0.06 0.16 0.07 0.19 0.04 0.09 Haze (%) < 0.20 < 0.20 < 0.10 0.10 0.20 0.04 0.10 0.20 Dielectric Constant (1 MHz) 2.73 2.51 2.29 2.61 2.87 3.10 2.88 2.58

1. _{UVV curable for all products except LOCTITE}®_{5192 & LOCTITE}®_{5192DM, while it needs to be tested according to actual conditions.}

Direct Bonding

Selector Guide

Cover Lens / ITO

LCD Module

Dam LOCA LOCA

LoctitE® _{7389 - primer for LoctitE}® _3196pr

Blue Green Clear Color

Acetone Solvent

1 - 2 Viscosity (cP @ 25 °C)

0.8 Specific Gravity

10 – 20 seconds Evaporation Time

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Selector Guide

Introduction

Effective cleaners are critical to ensuring that a manufacturing process has the lowest total

cost of ownership. Henkel has developed two cleaners that are developed specifically for

LOCTITE LOCAs. LOCTITE

®

_{SF 7190 is a hand wipe cleaner designed to remove dust, finger}

prints and small cured particles of LOCA. This is a fast evaporating solvent that is designed

for manual processes. LOCTITE

®

_{SF 7191 is a slow evaporating, high flash point solvent that is}

designed for automated processes that will remove the LOCA after it has been fully cured.

These cleaners are compatible with all LOCTITE

®

_{LOCAs except:}

• LOCTITE

®

_3193HS

• Any LOCTITE

®

_{LOCA on SiO2 hard coat}

common materials

• ITO coated glass

• Glass

• PMMA

typical gaps

• ~100 - 300 micron

characteristics

LoctitE

_{hand wipe cleaner}

®

Sf 7190

LoctitE

_{fully cured cleaner}

®

Sf 7191

Chemical Type Hydrocarbon Limonene

Physical State Liquid Liquid

Color Colorless to light yellow Colorless to light yellow

Odor Medium solvent odor Citrus odor

Flash Point (CC) ( °C) < 5 °C 35 °C

Specific Gravity

(25 °C) 0.70 - 0.80 0.92 - 0.95

Solubility in Water

(kg/m3₎ Not soluble Can be emulsified in water

Solubility in Acetone Miscible Miscible

Evaporation Time 5 - 10 seconds < 20 minutes

LOCA Cleaner

typical hand wipe cleaning process

1.

Dip the clean cloth, q-tip, wipe, etc… into the cleaner.

2.

Manually wipe the surface removing the LOCA residue and other contaminations.

3.

If necessary, perform a final wipe with IPA or

ethanol to reduce the evaporation time.

typical fully cured cleaning process

1.

Disassemble the display to expose the cured LOCA. This is normally done via a wire cutting process.

2.

Soak the cured LOCA in the cleaner for an extended period, normally 0.5 to 2 hours, using a soaked cloth, dipping process or spraying process. The exposure time will vary by the LOCA type, thickness, substrate type, etc.

3.

If needed, use a plastic squeegee to remove large areas

of softened LOCA.

4.

If needed, use LOCTITE®_{SF 7190 hand wipe cleaner to} remove any small cured particles of LOCA.

5.

If needed, manually wipe surface with IPA or ethanol to reduce the evaporation time.

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Selector Guide

Introduction

OGS (or G2) touch panel in some manufacturing processes requires temporary bonding

adhesive to temporarily fixate pieces of small glass after chemical strengthening on a large

carrier glass and debond them after ITO patterning. Henkel’s LOCTITE

®

_{3214 and 3215 with}

proven commercial success provide a solution for the manufacturing of OGS touch panels.

Key benefits:

• Can resist 240 °C for 3 hours with no delamination or cracking

• No contamination to photoresist or ITO deposition processes

• Resistant to solvent exposure with no delamination or cracking

common materials

• Glass after chemical strengthening

• Carrier glass

Temporary Bonding Adhesive

characteristics

LoctitE

®

₃₂₁₄

_LoctitE

®

₃₂₁₅

Chemistry Acrylate Acrylate

Curing Method 1 _UV _UV

(@ 100 mW/cm2_{UVA, MPMA UV Source)} 8,000 8,000

Viscosity (cP @ 25 °C) 3,100 - 5,000 10,500 - 15,500

Hardness (Shore 00) 64 68

Shear Modulus-G' (Kpa, Rheometer) 230 265

Elongation 100% 100%

Refractive Index 1.49 1.50

Transmittance (%) (average 380 - 780 nm) > 98 > 98

Volume Shrinkage (% ) 1.95 1.75

Adhesion - Glass to Glass, 100 μm (MPa) 0.9 1.2

Yellowness (b*) 0.46 0.48

Haze (%) 0.19 0.27

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Product Selector Guide

characteristics

cover Lens Bonding

direct Bonding

dam

temporary Bonding

LoctitE® 3192 LoctitE® 3193hS LoctitE® 3194 LoctitE® 3195 LoctitE® 3800 LoctitE® 3191 LoctitE® 3196 LoctitE® 3196pr LoctitE® 3198 LoctitE® 3199 LoctitE® 5191 LoctitE® 5192 LoctitE® 5193 LoctitE® 3195dm LoctitE® 3198dm LoctitE® 3199dm LoctitE® 5191dm LoctitE® 5192dm LoctitE® 3214 LoctitE® 3215

Chemistry Acrylic Acrylic Acrylic Acrylic Acrylic Acrylic Acrylic Acrylic Acrylic Acrylic Silicone Silicone Silicone Acrylic Acrylic Acrylic Silicone Silicone Acrylate Acrylate

(80 ºC /1 hour) UV UV UV UV UV UV UV / 7389 primer UV UV UV UV / Moisture UV / Moisture UV UV UV UV UV UV UV

(@ 100 mW/cm2_{UVA, MPMA UV Source)} 4,000 3,000 2,000 3,000 2,000 1,000 3,000 3,500 2,000 1,000 1,000 - 3,000 5,000 1,000 - 3,000 3,000 2,000 1,000 1,000 - 3,000 5,000 8,000 8,000

Viscosity (cP @ 25 ºC) 4,000 - 5,000 4,600 - 6,800 1,800 - 2,800 3,000 - 4,000 2,500 - 3,500 1,800 - 2,800 3,200 - 4,200 3,200 - 4,200 3,600 - 5,200 1,800 - 2,800 2,200 - 3,200 3,500 - 5,500 2,400 - 3,400 30,000 - 40,000 22,000 - 34,000 > 50,000 32,000 - 47,000 40,000 - 60,000 3,100 - 5,000 10,500 - 15,500

Hardness (Shore 00) 56 ShA 65 60 22 45 5 11 3 5 8 68 65 70 60 16 20 50 42 64 68

Shear Modulus-G' (Kpa, Rheometer) 83 8,830 78 42 100 10 17 16 13 14 119 - 208 70 114 - 205 150 100 30 58 - 126 47 230 265 Elongation 100% 300% 150% 250% 1000% 300% 300% 200% 700% 400% 130% 100% 120% 150% 400% 300% 270% 150% 100% 100% Refractive Index 1.49 1.51 1.51 1.51 1.47 1.47 1.51 1.51 1.52 1.47 1.41 1.41 1.41 1.51 1.53 1.48 1.41 1.41 1.49 1.50 Transmittance (%) (average 380-780nm) > 99 > 99 > 99 > 99 > 99 > 99 > 99 > 99 > 99 > 99 99.61 > 99 99.7 > 99 > 99 > 99 99.45 > 99 > 98 > 98 Volume Shrinkage (% ) 3.00 3.10 3.00 1.56 3.00 1.60 1.39 1.26 1.10 1.60 < 0.50 0.54 < 0.70 1.30 1.10 1.60 < 0.50 0.40 1.95 1.75

100 μm (MPa) 1.1 7.6 5.0 1.2 1.6 0.7 1.0 0.9 0.7 0.6 0.3 0.4 0.5 0.9 0.8 0.5 0.4 0.7 0.9 1.2

Adhesion - Glass to Polarizer

(Nitto Denko AG 254 μm gap) (MPa) - - - - 0.86 0.20 0.37 0.33 0.29 0.27 0.17 0.59 0.23 1.00 0.76 0.75 0.21 - - -Adhesion - Glass to Polarizer

(LG Bare 254 μm gap) (MPa) - - - - 0.85 0.19 0.21 0.20 0.24 0.25 0.23 0.63 0.23 0.90 0.73 0.44 0.15 - -

-Yellowness (b*) 0.30 0.10 0.01 0.41 0.10 0.05 0.18 0.09 0.06 0.16 0.07 0.19 0.04 0.51 0.21 0.10 0.14 0.33 0.46 0.48 Haze (%) < 0.20 0.09 0.12 < 0.20 0.11 < 0.20 < 0.20 0.20 < 0.10 < 0.10 0.20 0.04 0.10 0.10 0.02 0.10 0.20 0.17 0.19 0.27 Dielectric Constant (1 MHz) 4.69 3.24 2.83 2.45 3.93 2.73 2.51 2.58 2.29 2.61 2.87 3.10 2.88 2.38 2.63 2.71 2.78 2.85 - -Ordering Information IDH Number 50 ml 1578031 1577094 1538409 1544709 1880142 1755709 1592427 1800005 1712267 1734856 1826856 1606702 1809254 1565002 1738829 1734849 1831542 1602358 1763816 1749793 1 kg 1559815 1559814 1537894 1541655 - 1536154 1591827 1800002 - 1734864 1827480 - - 1564703 1738785 1734848 1831625 1602333 - -Other - - - 1610566 (2 kg) 1880141 (2 kg) - - 1800269 (2 kg) 1701583 (2 kg) - 1827067 (2 kg) 1608213 (300 ml)_{1608215 (18 kg)} 1809250 (300 ml) 1809511 (18 kg) - - - 1763707 (2 L) 1749795 (2 L)

1. _{UVV curable for all products except LOCTITE}®_{5192 & LOCTITE}®_{5192DM, while it needs to be tested according to actual conditions.}

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Cleaners