F u n c t i o n a l F i l m s

グンゼ株式会社 電子部品事業部

GUNZE Electronic Components Division

High Light-fast IndiumTin Oxide FIlm

MultifunctionalOptical Clear Adhesive

High HardnessHigh Durability Film

Functional FilmsHigh-functionality films from Gunze help to achieve higher added value in the market.

High-functionality films are at work in a variety of fields, including electronic components, automobiles, building materials, medicine, and food packaging. These films require a high level of mechanical durability to withstand pro-cessing, environmental durability to withstand use, and other similar charac-teristics. Optical performance is also necessary for ensuring clean, beautiful operation of displays. There are increasing opportunities for people to use touch panels in consum-er products like smartphones and tablet PCs, as well as applications like ordering systems in restaurants and car navigation devices. Touch screens have become a routine part of modern life. Going forward, these devices will function as daily necessities, and take on forms that can be operated easily by anyone. High-functionality films are used here as well, and we are continuing their evolution. By using the technology we have cultivated in the develop-ment of high-functionality films for optical applications, Gunze develops and sells high-functionality films that can be used not only for optical applica-tions, but also in many other products. We help achieve even higher added value in various markets by exploiting thin layer technologies for high hard-ness and optical performance.

By using our unique optical design technology, we perform deposition of ITO (Indium Tin Oxide), a transparent, electrically conductive film. We offer ITO films suitable for automotive and outdoor applications, with superior light-fastness while maintaining high visibility.

OCA (Optical Clear Adhesive) has high transparency, ability to track printing level differences in decorative printing, and measures to address issues of peeling and air bubbles. At the same time, it is provided with multifunctionality to suppress migra-tion, cut UV rays, and resist outgas-sing.

This film, with a maximum pencil hardness of 9H, was created through organic-inorganic hybridization. It is an optical film which, in addition to high hardness, has both high heat resis-tance and high light-fastness.

1

●Features

Transparent Conductive Film Resistant to UV Rays

●What is ITO film?In this film, ITO̶indium tin oxide, whose main raw material is the rare metal In (indium)̶is deposited on a film. ITO has the distinguishing feature of being highly transparent and electrically conductive, and is used in the electrodes for displays and similar devices. However, since it is metal, special technology is needed to deposit it on a thin, flexible film.

●Development of film materials using core technologiesGunze is working to develop products that make use of the functional thin film formation technologies for film surfaces (sputtering, wet coating) that we have cultivated for optical applications. In films used as a transparent, conductive material, ITO is deposited onto a film surface with a thickness of a few tens of nanometers, but if this technique is used alone, the patterning of the ITO film ends up being visible (Fig. 1). This is a fatal issue for displays and other optical applications, and it is essential to ensure this patterning cannot be seen. In addition, ITO film has a tendency to degrade when exposed to sunlight for a long time, and this was previously an issue for use in automobiles and outdoors. Using our original optical design technology, we at Gunze improved this problem, and thus were able to develop and offer transparent conductive film that is resistant to UV rays.

●Crystallization of metal filmCrystallization of the metal film is essential for ITO film. Ordinarily, commer-cial ITO films are sold while still uncrystallized, and annealing treatment is performed on the buyer side. At Gunze, we perform crystallization with our in-house annealing equipment, and thereby provide ITO film with a stabi-lized resistance value.

ITO film has outstanding light-fastness, and is suitable for automotive and outdoor applications. The whitening phenomenon, which occurs due to long-term exposure to sunlight, has been improved (see Fig. 2).

Resistant to degradation due to UV rays!

High-sensitivity, low-resistance ITO film!

●Lower resistance

●Lineup

To realize larger screens for applications such as displays, it is necessary to reduce the resistance of transparent conductive film. However, lowering resistance makes it even more difficult to provide the invisible characteristic. Gunze is working to lower resistance while improving this problem and maintaining high visibility, and our aim is to produce high-sensitivity ITO films suitable for large-sized applications.

(Fig. 2) Whitening phenomenon

After improvement

(Fig. 1) Invisible characteristic

With Without

Image) Xenon lamp irradiation test, after 500 hr at 60 W/m2, comparison of surface condition of ITO film (comparison with our company's product)

【Basic composition】ITO

Index Matching Layer

Clear Hard Coat

Clear Hard Coat

PET Film

*The above are actual measured values, not guaranteed values.

Model no.Film thickness Surface resistance value Total light transmittance HAZEb* Invisible characteristic

125μmIPF-19H125-01 IPF-20G125-01 IPF-21H188-01 IPF-22G188-01

188μm80Ω/□89%1%2

GOOD

150Ω/□89%1%1.8GOOD

80Ω/□89%1%2

GOOD

150Ω/□89%1%1.8GOOD

Material: PET250

200

150

100

50

0

ITO resistance value （Ω/sq）

2012 2013 2014 2015 2016 2017 2018（year）

Reduction of resistance

150

8050

Ω/□

Ω/□Ω/□

*Annealing is a type of heat treatment for removal, by heating, of internal strain that arises in processes where films and other resins cool.

Before improvement

High Light-fast Indium Tin Oxide Film

2

●NNX Series / NNE Series : Adhesives for suppressing shorting of metal wiring

●What is OCA (Optical Clear Adhesive)?OCA is an optical adhesive sheet in film form, used for bonding. It is used when bonding various adherends such as glass, acrylic, polycar-bonate, and film. Adhesive materials used in displays must be optical-ly uniform and transparent, and there must be no peeling or air bub-bles, because this will directly affect display performance.

●High-quality, high-performance adhesive (OCA) is used in display devices, which are becoming increasingly thin and lightweight. OCA must have high transparency, ability to track printing level differences in decorative printing, measures to address issues of peeling and air bubbles, and functions to suit the use environment. Gunze is working to solve these problems and improve the function of OCA, by making use of material design and coating technology. In addition to the issues of peeling and air bubbles, there is a need for characteristics such as not degrading under UV rays, and thus the necessary charac-teristics of OCA must be selected according to the adherend to be bonded. As examples of high-functionality OCA, we offer our own OCA provided with functions to suppress migration, cut UV rays, and resist outgassing.

There is often metal wiring on the surface of the adherend. If a voltage is applied in an environment with a high level of moisture (humidity), a problem occurs with silver and other metal wiring in that shorting occurs due to movement of ionized metal between electrodes. This phe-nomenon is called migration. Gunze enables suppression of migration with an adhesive based on our unique blending design.

Suppressing migration

【Basic composition】

【Adherend】

【Test sample】

Suppressing migration

Ag Ag Ag

PET Film

PET Film

Adhesive

Ag Ag AgTest conditionsAg wiring: L/S 60/90μm60℃ 95%RH 240 hrDC16V

NNX Conventional product

Does not occur Occurs

OCA

Release PET

Release PET

OCAOCA

Glass+Film

Film+Film

●NNE Series : Adhesive that protects the underlayer from UV rays

Previously, there was a problem that the underlayer degraded and yellowed when installed outdoors with long-term exposure to sunlight. This OCA is provided with a function for cutting UV rays, while maintaining migration suppression functionality. This is suitable for protect-ing the underlayer from UV ray degradation and improving light-fastness.

Cutting UV rays

Transparent Optical Adhesion

Multifunctional Optical Clear Adhesive

Development of adhesives by exploiting core technologies

3

●Outgas-resistant OCA : Adhesive that suppresses occurrence of air bubbles due to outgassing

Adherends have various materials, properties, and characteristics, and thus there is a need to select a suitable OCA. Particular care is needed for plastic substrates such as acrylic or polycarbonate. If an OCA with no countermeasures is used, there will be problems with air bubbles forming as time passes. This is called “outgassing.” These plastic substrates have high water absorbency, and it seems that one factor underly-ing outgassing is that moisture remaining in the substrate in the fabrication process is affected by the passage of time and changes in the environment, and turns to gas. What connects the adherends is OCA. Gunze proposes OCA provided with an outgas suppression function as well as a function to cut UV rays, a combination which was previously regarded as difficult.

Polycarbonate compatible, Developed product

Testcomposition

Testconditions

Conditionphoto

PolycarbonateOutgas-resistant OCAGlass

85℃／90%R.H.×500 hr

85℃／90%R.H.×500 hr

PolycarbonateGeneral adhesiveGlass

【Test sample】

Suppression of underlayer degradation by cutting UV rays

Design to suppress yellowingBy using our company's blending design, we both provide UV absorption, and suppress the increase in yellowing (b*)

Blank glass

PET Film

ITOAdhesive

Test conditions：Xenon lamp 60 W/m2 240 hr(irradiation from blank glass surface side)

NNE75 Conventional product

Suppresses yellowingΔE=0.2

Yellowing occursΔE=2.7

Outgas-resistantOCA

Generaladhesive

Item

b*

ΔE

b*

ΔE

0.4

-

0.3

-

0.4

0.06

0.6

0.28

Initialvalue

After120 hr

■Outgas-resistance function ■UV-cutting function

No air bubbles or peeling

Air bubbles and peeling occur

Test conditions: Xenon lamp 60 W/m2

【Adherend】

OCA

●Lineup

Thickness

Total lighttransmittance

HAZE

Adhesive strength

Migration suppressionUV cuttingOutgas-resistance Acid free

Adhesivefunctions

Model no.NNX Series NNE Series

μm

%

%

N/25mm

90.4

0.5

10.0

NNX50M

●

●

NNX75M

●

●

NNE75M

●

●

●

NNEA0M

●

●

●

Outgas-resistant OCATBD

●

●

●

NNXA0M

●

●

NNXA2M

●

●

JIS K7361-1 Measurement sample composition: Film / Adhesive layer / Blank glass

JIS K7136 Measurement sample composition: Film / Adhesive layer / Blank glass

13.5 (for glass)12.2（for polycarbonate） Conforms to JIS Z0237

Measurement method

90.5

0.5

11.0

90.5

0.5

11.5

90.5

0.5

13.5

50 75 100

90.5

0.5

10.8

90.6

0.5

11.7

75 100

90.3

0.6

100125

*The above are actual measured values, not guaranteed values.

Glass+

Polycarbonate film,acrylic film

【Adherend】

OCAOCA

Glass+Film

Film+Film

provided withUV-cutting(　　　　)

Functional Films

4

Pencil hardness expresses the hardness of coated films, and is stip-ulated by a JIS standard. Pencil hardness is used when measuring the scratch resistance of resin, plastic, and coated films, and in the JIS standard there are 17 levels in the range 6B‒9H. HD film achieves the maximum value of 9H.

The term “glass transition point” is used for plastic. The motion of molecules is limited at or below a certain temperature, and in this case the plastic exhibits the property of hardness. However, when heated to that temperature or higher, the plastic enters a state where molecules move more easily, and in this case it exhibits the property of softness. This temperature is called the glass transition point (Tg). With HD film, a glass detection point is not detected. Even at high temperatures, it does not easily soften, and it has heat resistance to fabrication processes and similar stresses. (200°C)

Resistant to scratching!

High durability!

■Surface hardness comparison

■ High durability

50 100 150 200 250

←endo

Heat Flow（mW）

Temperature（℃）

0.5

Glass transition pointHighly heat-resistant

film substrate

COP (CycloOlefin Polymer)

Polycarbonate

DSC measurement

Ordinary3H PET

9H HD

Pencil hardness 4H～9H 3H H 3H H

PETFilm type PC PES COPHD

Tg（℃）

UV ray durabilityXenon lamp　60W/m2

>200

◯

69

△

150

△

223

×

160

△

PETFilm type PC PES COPHD

Protection FilmHD

Film

Protection Film

【Basic composition】

HD FilmPET

Hard Coat

Hard Coat

●What is HD film (high-durability film)?A hard coat is essential to provide PET film with hardness. However, there have been problems such as the high diffi-culty of achieving 9H, and degradation of the hard coat due to UV rays. Through mold fabrication, Gunze has realized films in organic-inorganic hybrid material units. Hybridiza-tion allows this film to simultaneously achieve high hard-ness, high heat resistance, and high light-fastness.

●For applications requiring high durability

HD film has a maximum pencil hardness of 9H, and reduces weight and thickness while maintaining hardness on a par with acrylic sheet. It is suitable for applications requiring high durability such as car navigation systems, and the out-ermost cover of smartphones and tablet PCs.

High-Hardness Film

High Hardness High Durability Film

5

In the case of a PET film provided with a hard coat, there is the problem that degradation occurs due to UV rays.

HD film is formed in a single layer, and since there is no hard coat, there is no separation due to UV rays.

●Lineup

*The above are actual measured values, not guaranteed values.

■UV ray durability (0hr) (528hr)

HDFilm

Hard coatPET Hard coat separation

■Optical isotropy

■Optical characteristics

Cross-section of film

Clear appearance

AG appearance

Non-filler, bumpy profile formed on surface

Ordinary PET HD Film

Retardation（nm） <10 >100 <10 12 <10

PETFilm type PC PES COPHD

200μm

91~92%

1.0%以下

9H

68°

>200

<10

4%

550gf×100times,no scratches

100μm

90~91%

16±4%

9H

85°

>200

<10

<2%

550gf×100times,no scratches

Film thickness meter (contact type)

JIS K7361-1

JIS K7136

JIS K5600（750gf）

Steel wool (#0000)

Water

DSC method

KOBRA

380 ～ 780nm

HD900CCSA HD900AG7CS4 Remarks

Film thickness

Total light transmittance

HAZE

Pencil hardness

Steel wool

Contact angle

Glass transition point（Tg）

Retardation（nm）

Average reflectance

Model no.

The characteristic of having two or more indices of refraction, due to factors such as crystal structure or macromolecule orientation, is called "birefrin-gence." Birefringence is expressed by the refractive index difference, and the product of the refractive index difference and film thickness is called retar-dation (phase difference). Materials such as PET film exhibit birefringence and have high retarda-tion, and thus when light passes through, the light interferes and produces iridescent unevenness. HD film has low retardation, and iridescent unevenness does not occur, even through polar-ized sunglasses.

Anti-glare (AG) treatment is one way to provide low-reflection functionality. AG treatment is gen-erally achieved by adding particles a few μm in size (called filler) to hard coat. With HD film, AG treatment can be performed by directly forming a bumpy contour on the surface, and there is no need for application of hard coat.

No occurrence of iridescent unevenness!

Functional Films

F I N E R I N T E R F A C Ec r e a t e s b e t t e r r e l a t i o n s h i p s .

●Please be aware that specifications are subject to change without prior notice due to product improvement. ●This catalog is current as of July 2019.

GUNZE LimitedELECTRONIC COMPONENTS DIVISION

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Contact us

http://www.gunze.co.jp/denzai/