OBA Carrier
and co-binder
for Coated Paperand Board

Kuraray Poval™

Why is paperand boardcoated?
Paper and board are coated in order to improve the printability. A pigment
coating increases the smoothness and reduces the porosity of the paperand board which influences ink absorption. When printing on a coated paper
the ink stays more on the surface of the paper giving a higher print gloss
and a more brilliant and more detailed print. The coating colors consist ofpigments like clay and calcium carbonate, latex and additives. The additives
are crosslinkers to increase wet strength, optical brightning agents (OBA)
to increase whiteness and co-binders to give strength, water retention andviscosity to name a few.

OBA Carrier

Increased whitenessby using Kuraray Poval™
as a OBA carrier
CIE whiteness (D65, with UV) 1 part OBA

By adding Kuraray Poval™ to coating color containing opticalbrightening agent (OBA), the CIE Whiteness of the paper canbe increase with up to 15%. Kuraray Poval™ interacts with theOBA increasing the efficiency of the OBA. The recommended
addition level of Kuraray Poval™ is 1:1 ratio with the OBA,but further increasing the Kuraray Poval™ dosage will further
increase the CIE whiteness and also reduce whiteness reduction over time.

120115110105

10000,51,01,5 pts

Kuraray Poval™ 4-98

00,40,81,2 pts

low mwt NaCMC

02,04,06,0 pts

starchPigment coatings

Kuraray Poval™ as co-binderand water retention aid inpigment coatings
Kuraray Poval™ has multiple tasks in a pigment coating. Besides acting as a carrier of OBA it also acts as a binder andwater retention aid in the coating color. Polyvinyl alcohol isthe strongest binder available for paper coating and increasing the Kuraray Poval™ dosage will give possibilities to reduce
total binder amount and through this reduce costs.
In the example on the right we have reduced the total binder
content from 10,5 parts to 9 parts and at the same time increasing the dry strength. We have reduced the SB-latex levelfrom 10 parts to 7 and increased the Kuraray Poval™ content
from 0,5 parts to 2 parts.

Kuraray Poval™ has a positive effect on water retention. Whenincreasing the the amount of Kuraray Poval™ in your coatingrecipe the ÅAGWR water retention will be reduced.

Coating colour
Calcium Carbonate: 80 pts
Clay: 20
OBA: 0,5 pts
CMC: 0,3 pts
Solid content: 66,7 %Dry pick, m/s
151413121110
98Parts PVOH 0,512

SB latex

1097Total binder

10,5109ÅAGWR water retention, g/m 2140
120
100
8060
40
20
0
00,51

1,52Parts Kuraray Poval™

Kuraray Poval™,
Elvanol™ and Exceval™
products for coatedPaper and Board
Low molecular weight and fully hydrolyzed KurarayPoval™ is commonly used as co-binder and OBAcarrier in coated paper and board. Which product isused depends on what the viscosity requirements areand if direct food contact approval is needed.
Please contact your local Kuraray office
to discuss the right productfor your needs.

2,5

3

3,5

Adding value toyour products –worldwide
Kuraray Poval™, Exceval™, Elvanol™ and Mowiflex™ are the trademarks for polyvinyl alcohols
made by Kuraray. Their key characteristics — outstanding film-forming properties and high binding strength — add real value to your products. Our polymers are water-soluble, highly reactive,crosslinkable and foamable. They have high pigment binding capacity, protective colloid characteristics and thickening effects. The physical and chemical properties of Kuraray Poval™ makeit ideal for a wide variety of applications, ranging from adhesives through paper and ceramics
to packaging films. Many of our polymers are food contact-approved and thus suitable for foodapplications. Ecologically Kuraray Poval™ is advantageous due to its biodegradability and the factthat combustion does not generate residues. It is available in various particle sizes from granules
to fine powders.
Kuraray produces its wide range of Kuraray Poval™ grades in Japan, Singapore, Germany and theUSA. Kuraray’s global production and service network make us your partner of choice for innovative high-quality PVOH resins.
Kuraray – Here to Innovate.

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

09_2021