APPLICATION INFORMATIONFULACOLOR ADDITIVES FOR HIGH-SPEED INKJET PAPERS

K-A 4

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FULACOLOR additives for high-speed inkjet papers

Contents
03 Introduction
04 FULACOLOR pigments
05 Inkjet printing performance
07 Formulating with FULACOLOR
08 Cost effectiveness09 Benefits of FULACOLOR

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Introduction
Inkjet development
The development of high-speed inkjet printers is opening
up new markets for inkjet printing as a result of theability to produce short print runs of documents in fullcolor and with variable information.
These features are especially suited to a number ofmarkets previously dominated by traditional offset
printing, including:• Brochures• Labelling• Packaging• Magazines• Décor paper• Trans-promotional

NoteTo ensure the best appearance
and full functionality, please
open in Adobe Acrobat.

Substrate requirements
These developments pose a number of challenges tothe paper supplier in that:•	uncoated papers do not deliver the image quality
required•	silica-coated papers deliver excellent quality, but thecost is too high for most new markets•	calcium carbonate papers cost less, but the imagequality is usually not acceptable04FULACOLOR additives for high-speed inkjet papers

FULACOLOR pigments
FULACOLOR coating pigments have been designed tocombine image quality needs with the cost effectivenessrequired in paper coatings. When correctly dispersed andformulated, these pigments can be:• used alone or as a partial replacement for silica to provide
a cost-effective alternative without a significant loss ofimage performance• combined with calcium carbonates to produce asignificantly improved image color density whilst
maintaining the low-cost base

SEM image of FULACOLOR particle
Magnification (x 40000)

FULACOLOR is produced from the natural mineralbentonite by controlled treatment with acid, otherwise
known as an “acid-activated clay”:

Production process of FULACOLOR

Treat natural
betonite with acid

Acid leaches awaysome structure

Controlled porosity
is achieved

Properties aredeveloped above
the natural clay

4 µm
G. 01

G. 02

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FULACOLOR additives for high-speed inkjet papers

Inkjet printing performance
Color intensity

Standard inkjet images for color evaluation

The intensity of colored images and text is a primaryconsideration in inkjet technology markets. The highporosity, surface area, and liquid absorption capacity ofFULACOLOR ensures that ink molecules are fixed close to
the coating surface to produce a clear, bright, and vivid
image. The high absorption strength ensures that the image
is permanent and cannot be easily rubbed off. Whencorrectly formulated, paper coatings with FULACOLOR
pigments deliver images of enhanced intensity across thecolor spectrum. In addition, the images are superior to
uncoated or standard calcium carbonate-coated papers
when either dye or pigment-based inks are used (G. 03).
The prints are also comparable with silica-coated papers.

Uncoated paper

FULACOLOR coated paper
G. 03

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FULACOLOR additives for high-speed inkjet papers / Inkjet printing performanceLine bleed/sharpness/clarity

Drying time

A further requirement of inkjet coatings is to provide sharp,clear, and uniform images and text resulting in prints withexcellent definition, readability, and clarity. As shown inG. 04, coatings that contain FULACOLOR-XW produce asharper image than uncoated papers. When also combinedwith a calcium carbonate, it is possible to achieve a linesharpness and image uniformity comparable to thatdelivered by high-cost silica pigments.

As the printing speed increases, the ink drying rate becomes
ever more critical. Rapid drying is essential to prevent
problems of image smearing.

Improvement on ink drying timewith FULACOLOR-XW

Sharpness evaluation images

Uncoated paper

FULACOLOR-XW
coated paper

A combination of controlled particle size distribution andporosity control ensures that coatings with FULACOLOR
pigments have the required pore structure to rapidly remove
the ink solvent from the surface whilst holding the colored
ink molecules at or near the surface and so that they remainbright and clear (G. 05).

FULACOLOR-XW +CaCO3
coated paper

G. 04

5 seconds

5 seconds

10 seconds

10 seconds

Uncoated paper

FULACOLOR-XW
coated paper

G. 05

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FULACOLOR additives for high-speed inkjet papers

Formulating with FULACOLOR
To achieve the optimum performance of FULACOLOR-XW,
complete dispersion is required. For best results, FULACOLOR
should be dispersed in water at a pH of 7.5. The following
procedure for incorporation is highly recommended:

FULACOLOR
dispersion• Weigh the quantity of water required for the desired solids
content into the mixing vessel• Add a caustic reagent to adjust the pH value in the rangeof pH 7– 8 (usually sodium hydroxide is the preferredreagent)• Add FULACOLOR-XW in several aliquots, allowing time forcomplete dispersion after each addition before the next
• As the solids increase, the viscosity will also increase,which may necessitate reducing the aliquot size
• Once FULACOLOR-XW has been added and fully
dispersed, the other formulation components
can be added• The pH may require adjustment at the end for therelevant application

Note:
The amount of water is guided by
the equipment available, thecoating method, coat weight, etc.
The size of the individual aliquots
and the dispersion times dependon the equipment.
Other additives such as wetting
and dispersing agents, defoamers,
optical brighteners, and biocides
can be added as required.

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FULACOLOR additives for high-speed inkjet papers

Cost effectivenessThe inkjet performance enhancements and handling
improvements may be achieved without incurring the highmaterial costs associated with silica coatings. Combinationsof an appropriate ground calcium carbonate andFULACOLOR pigments can provide a particularly costeffective solution. Typical basic formulations to achieve
this performance are shown in Table T. 01.

Relative Cost (%)

Cost of inkjet formulations relative to silica

Coating materials costs

100806040

Formulation

Dry Parts

20AB

FULACOLOR-XW

2040

Ground calcium carbonate

8060

Polyvinyl alcohol11015

Cationic fixative

10102

1

Partially hydrolysed

2

PolyDADMAC fixative required to fix anionic dye based inks

0Ground calcium carbonate

FULACOLOR
formulation A

FULACOLOR
formulation B

Silica

G. 06

T. 01

Formulation A will offer highly cost-effective performancesuitable for most duties, whilst formulation B will offer
better performance for demanding applications at a slightly
increased cost (G. 06).

FULACOLOR additives for high-speed inkjet papers / Cost effectivenessRheology of FULACOLOR dispersions
FULACOLOR pigments have been designed to facilitate thepreparation of coating slurries to a high solids content
relative to silica-based coating colors (G. 07).
This not only improves the quality of the coating but canincrease the coating rate and significantly reduce the drying
load of the coated paper, thus delivering major benefits withrespect to coating production costs.

Viscosity as a function of slurry solids

Viscosity (mPas)

09

1000
800
Silica600
400
FULACOLOR-XW
200015202530

354045Solids (wt %)

G. 07

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FULACOLOR additives for high-speed inkjet papers

Benefits of FULACOLOR
The carefully controlled chemistry, particle size, and porosityof FULACOLOR pigments deliver many benefits to the user,
including:

Fast ink drying

High print
definitionHighly cost-effective
performance

Excellentcolor density

Minimal color/line bleed

MinimalstrikethroughHigh coating slurrysolids capacity

Compatibility withall inkjet ink types

03/2022
K-A 4
BYK-Chemie GmbH
Abelstraße 4546483 Wesel
GermanyTel +49 281 670-0
Fax +49 281 65735

ADD-MAX®, ADD-VANCE®, ADJUST®, ADVITROL®, ANTI-TERRA®, AQUACER®, AQUAMAT®, AQUATIX®, BENTOLITE®, BYK®, BYK®-DYNWET®,
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The information herein is based on our present knowledge and experience. The information merely describes the properties of our products but noguarantee of properties in the legal sense shall be implied. We recommend testing our products as to their suitability for your envisaged purpose
prior to use. No warranties of any kind, either express or implied, including warranties of merchantability or fitness for a particular purpose, are maderegarding any products mentioned herein and data or information set forth, or that such products, data or information may be used without infringing
intellectual property rights of third parties. We reserve the right to make any changes according to technological progress or further developments.
This issue replaces all previous versions.