Adding value toyour products –worldwide

Exceval™ –designed topreserve thegood taste

Kuraray Poval™, Exceval™, Elvanol™ and Mowiflex™ are the trademarks for polyvinyl alcohols
made by Kuraray. Their key characteristics — outstanding film-forming properties and highbinding strength — add real value to your products. Our polymers are water-soluble, highlyreactive, crosslinkable and foamable. They have high pigment binding capacity, protective
colloid characteristics and thickening effects. The physical and chemical properties of Kuraray
Poval™ make it ideal for a wide variety of applications, ranging from adhesives through paper andceramics to packaging films. Many of our polymers are food contact-approved and thus suitablefor food applications. Ecologically Kuraray Poval™ is advantageous due to its biodegradability andthe fact that combustion does not generate residues. It is available in various particle sizes fromgranules to fine powders.

Exceval™

Exceval™

Kuraray produces its wide range of Kuraray Poval™ grades in Japan, Singapore, Germany andthe USA. Kuraray’s global production and service network make us your partner of choice forinnovative high-quality PVOH resins.

Non-metallised film
applications

Metallised film
applications

Kuraray – Here to Innovate.

Packaging films preserve a wide range of various food. Typically 2-layer constructions of PE, PP, PET and PA are usedin the food industry − among other things for confectionery, bread, frozen meat products, rice and cereal products.
Most of these materials are supplied as finished films withFlexi-printing. A thin layer of Exceval™ of less than a few μm is
coated directly with or without primer on these different substrates. In order to protect Exceval™ from humidity, Exceval™
can be top-coated or laminated with substrates that have low
water vapour permeation. PE is mainly used as welding layer
in this construction. Other typical applications of transparent
barrier films are, for example, lids to closed food trays.

Metallised film such as PET, SiOx-coated PET and new
high-barrier metallised BOPP are used in a wide variety offood packaging applications where either a high barrier orstriking appearance is required, for example, in crisp packaging (BOPP) or coffee packaging. In addition, vacuum-metallised papers are employed as liners for cigarettes, packaging
for pharmaceutical products, dairy products, confectionery
and gift wrapping, wet glue label and outer liner for carton.
Pinholes in a metallised substrate are the main pathway forpermeation. Pinholes account for the majority of the oxygen permeation but only for about 20% of the water vapour
permeation. Most of the water vapour permeation through ametallised layer is due to nano-scale defects on the surface.
The main way to improve the gas barrier properties of sucha construction is to perform the metallization on top of apolymeric gas barrier layer like Exceval™. With Exceval™ thepinholes will be filled with this polymeric gas barrier substrateand consequently the overall gas barrier performance of theRealisation increases significantly. Furthermore, the use ofExceval™ as a polymeric gas barrier layer will avoid the necessity of performing a seeding metallization process that
contributes significantly to the deterioration of the flexibilityof the packaging film.

Keeping it crisp and aromatic:
Exceval™ coatings provide excellent
protection for fresh food.

Exceval™ –Attractive
protection
for your food

Headquarters
Kuraray Co., Ltd.
Tokiwabashi Tower
2-6-4, Otemachi
Chiyoda-ku
Tokyo, Japan 100-0004
Phone: +81 3 67 01 1000
infopoval.jp@kuraray.com

Kuraray Poval™
product portfolio
Please contact your local
Kuraray office to discuss theright Kuraray product foryour needs.

Kuraray America, Inc.
2625 Bay Area Blvd.,
Suite 600 Houston, TX77058
United States of America
Phone: +1 800 423 9762

Kuraray Asia Pacific Pte., Ltd.
250 North Bridge Road
#10-01/02 Raffles City Tower
Singapore 179101
Phone: +65 6337 4123

info.kuraray-poval@kuraray.com

infopoval.sg@kuraray.com

Kuraray Europe GmbH
Philipp-Reis-Str. 465795 Hattersheim am Main,
Germany
Phone: +49 69 305 85 351

Kuraray China Co., Ltd.
Unit 2207, 2 Grand Gateway
3 Hongqiao Road, Xuhui District,
Shanghai 200030, China
Phone: +86 21 6119 8111

info.eu-poval@kuraray.com

infopoval.cn@kuraray.com

04_2023

Exceval™ –performancethat is simply
convincing

Exceval™

The solution
for barrier
requirements

Frequently
asked
questions

Oxygen Transmission Rate

Viscosityof Exceval™ compared to standard polyvinyl alcohol
at 20 °C, cm³.2μm·m¯²·day¯¹·atm¯¹

Exceval™ is the trademark of Kuraray’s chlorine-free barrier resin, especiallydesigned for the requirements of the barrier coating industry. The new
Ethylene-Modified copolymer is water-soluble like standard polyvinyl alcohol.
However, coatings made of Exceval™ absorb significantly less humidity at
average temperature conditions. Therefore, Exceval™ provides coatings withexcellent gas barriers, e.g. towards oxygen, nitrogen and carbon dioxide – evenat elevated relative humidity. Furthermore, the resulting coatings are highly
transparent and glossy, have a strong chemical resistance, and provide goodadhesion to metal as well as excellent printability.

Exceval™

of low-viscous Exceval™ grades
Viscosity (mPa·s)

PVA

50 °C

20 °C

1.000

100

10.000

10

1.000

1100

0.1

0.01

165

70

75

80

85

90

0510

relative humidity (%)

15202530

concentration (%)

How much material isrequired to achieve a high gas
barrier level?

How to dissolve Exceval™?

A dry weight of 1-2μm is enough to achieve ahigh gas barrier level (permeation less than 1
cm³·m¯²·day¯¹·atm¯¹).

Exceval™ should be dispersed in cold water andthen be heated to 95°C inner temperature andkept there for 2 hours. The solution should thenbe cooled down slowly.

How do I improve the barrier
properties?

of Exceval™ compared to standard barrier coating materials
at 20 °C, cm³.20μm·m¯²·day¯¹·atm¯¹

Upon storage at low temperature an Exceval™
solution may gel. Storage at elevated temperature as well as addition of isopropanol (IPA) will
reduce the gelling tendency.

PANHow can possible foaming ofExceval™ solutions be prevented during solving andapplication?

10010PVDC
MXD-61EVOH 26%
0.1Exceval™
0.01
0Because of the need to control gas and water vapour permeation simultaneously while providing mechanical performance,
the structure of a packaging film will consist of several layers,
each of them contributing to one or several properties of thefilm construction. A base layer that may be constituted ofpolyolefin materials, have low water vapour permeation andalso providing some mechanical resistance will be combinedwith an Exceval™ oxygen barrier layer. In such a structure
there are also further layers that provide specific functionalities like primers, adhesives, inks, etc.

Increasing the coating temperature will reducethe viscosity. Depending on the coating temperature the total solid content can be adjusted.
By increasing the solid content the drying time
can be reduced.

Storage of Exceval™ solutions!

Oxygen Transmission Rate

Exceval™

Exceval™ enables a barrier of less than 1 cm³·m¯²·day¯¹·atm¯¹(very high oxygen barrier) even at high degrees of relative
humidity. Exceval™ can be applied as a solvent free, chlorine-free and environmentally-friendly waterborne coatingon numerous substrates and provides superior barrier levelcompared to traditional coatings.

solutions are forming a film upon drying. Incontrast, PVDC needs elevated temperatures toenable particles coalescing to form a film.

1060

Applications devisedfor your products

How can I increase the coatweight?

102030

40

50

60

7080

90100

relative humidity (%)

The Oxygen Transmission Rateof a PE film coated with Exceval™ and metallised is analysed at 23 °C,65 % RH, in 100 % Oxygen atmosphere:

Oxygen Transmission Rate
cm³·m¯²·day¯¹·atm¯¹

InitialAfter 20 Cycles
Gelbo-Flex-Test

Towards O 2-Side

< 0.1

< 0.1

Towards N 2-Side

< 0.1

< 0.1

Exceval™
showoutss
perf tanding
ogas b rmanceeven arrier la as
yer −
afte
r2
of th 0 torsio
nse film.

Adding 10% isopropanol to Exceval™ will considerably reduce the foam formation in the dissolving vessel. The subsequent addition of IPA
reduces the foam formation on the gravure rolls.
IPA will also significantly improve the wetting ofExceval™ on the plastic substrate. Furthermore,
reducing the viscosity of the Exceval™ solution
contributes to a reduction of the foam formationon the gravure rolls.

What total solid content can I
prepare?
Typically a 10-15% solution should be made.

At what temperature do I
need to dry?
No specific temperature is needed as Exceval™

Crystallisation is the driving force behind thebarrier performance of Exceval™. Any temperature treatment will improve the barrier performance. Storage of the coated film at elevatedtemperatures (50°C for several days) will allow
the improvement of the gas barrier level.

How to improve the water resistance?
Crosslinking will improve the water resistance;
however, the crosslinking ratio will reduce thebarrier performance. A metal binding complex
is preferred in order to combine good water resistance while maintaining the excellent barrier
level.

Can I print on Exceval™?
Yes, it has a very good affinity printing inks.

Does torsion affect barrier
performance?
To estimate the flexibility of the packaging film,
the barrier properties are evaluated before andafter mechanical torsion (Gelbo Flex test). Even
after 20 torsions Exceval™ barriers demonstrate
outstanding performance.