Serv News
6
SYLOID® Matting Agents in Printing Inks
Printing Inks are mostly highly pigmented systems applied at
relatively low film thickness whose main visual feature is colour.
Gloss level is often a feature of secondary importance. However,
where reduced gloss or matting is desired, micronised silicas of
the SYLOID® type give excellent results.
Apart from matting, SYLOID® silicas also have other beneficial
effects in ink systems. These can fall into one of 3 categories:
• modification of surface properties
• modification of viscosity behaviour
• control of printing properties
The table alongside summarises the potential function of
SYLOID® silicas in different ink types and indicates the most
appropriate SYLOID® features in each case to aid grade
selection.
(1) Unnecessary for UV cured Inks
(2) This is not usually the primary property for which the
SYLOID grade was introduced
It should also be borne in mind that ink-makers often manufacture
and supply the overprint varnishes for their ink systems as well as
a variety of speciality coatings applied by methods in-common
with traditional printing processes. These may also be matted
depending on the desired final gloss of the printed or coated
surface. In such cases, the same general rules will apply as
COMMON
QUESTIONS
PHILIP GREEN, PATRICK
JOHNSON PAINT TECHNOLOGY
CONSULTANTS
NUMBER 7
What is flash rusting and how can I
prevent it?
Recently this is a question that we have
been asked quite frequently by people
who make premium quality water based
products based mostly on pure
acrylics or Styrene acrylics as well
as other polymer types.
Type of Ink
Desired Function
SYLOID® Grade
All
Matting
Fine untreated
(or treated) grades
SYLOID 244 or C
803
Offset Lithographic,
Letterpress and
Flexographic Inks
Surface properties
e.g. Anti-blocking,
Anti-set-off (1), Slip
Due to very low ink
thickness (1- 3µm),
generally finest
untreated grades
SYLOID 244 or C
803
Offset Lithographic,
Letterpress and
Flexographic Inks
Rheological properties. (2)
N.B. also in combination
with Pyrogenic
Silicas
and Bentonites
Depends largely on
application properties desired
Control of water
pick-up
SYLOID® 244
Offset Lithographic
Inks
for clear, unpigmented lacquers of low viscosity. Generally, the
relatively fine particle size, surface treated grades from the ED/C
series, e.g. SYLOID ED 30 or 7000 give optimum results.
possible to dry off the clean metal with hot
dry air.
One should clean the surface with a
water miscible degreaser and rinse to a
water break-free surface and allow to dry
prior to blasting or sanding. If washing
or wet blasting is used washing then an
amine type flash rust inhibitor should be
used in the water.
2. Although the metal was dried after
cleaning or de-rusting the cleaned metal
was left exposed to a humid/damp
atmosphere for more than 3- 4hours.
This type of flash rusting is a big problem
in very humid coastal areas, where the
There are 3 main causes of the
problem:
1. The surface preparation or
de-rusting of the metal substrate
involved a lot of water which was left in
contact with the cleaned metal and caused
the flash rusting.
The best way to prevent this type of
flash rust is to minimize the amount of
water present during cleaning and if
presence of salt aggravates the problem.
The only real method to minimize this
type of flash rusting is to prime the cleaned
and de-rusted metal as soon as possible
(certainly within 2 hours) or use a flash
rust inhibitor in the water.
3. A water based or water containing
primer or primer top coat was applied to
the cleaned and de-rusted metal and the
flash rust appeared with in 30 minutes of
application
This is in some ways both the easiest
and the most difficult type of flash rusting
to minimize
-easy because the addition of low level of
a flash rust inhibiting additive or pigment
will do the job,
-but difficult because if you choose
the wrong flash rust inhibiting additive
or pigment, not only will the flash rust
occur it could actually make it worse. It
all depends on the formulation, volume
solids, resin, pigment/extender and
solvent system being used and the
film build being applied.
Certainly from experience 3-5
g/Lt of Servochem’s Advantex will
help in a lot of situations as will
the using 1-2% of 10-15% solution
of Sodium Nitrite or Sodium or
Ammonium Benzoate. Also using
Modified Zinc Phosphates will often help
but sometimes even more powerful flash
rust inhibitors additives or pigments are
needed.
For further details/help contact the author or
your local Servochem branch.
PQI safety
while painting
THE ROHM AND HAAS Paint Quality Institute (PQI) strives to
create a more informed paint consumer and assists quality paint
manufacturers in their efforts to produce and promote quality
paints.
“Professionals from the PQI have compiled guidelines on
how to avoid unnecessary accidents while undertaking paint
jobs in industrial or commercial environments,” says Nita Jacob,
spokesperson for the Rohm and Haas Paint Quality Institute
(PQI) in South Africa. “Apart from taking extra care while painting,
important steps necessary to achieving the best possible results
include good surface preparation, purchasing quality pure acrylic
paints, using high quality brushes and tools and making sure the
area being painted is well ventilated.”
Use the correct tools
Good quality tools and brushes last longer, speed up a job and
apply the paint smoothly, which enhances durability. Brushes
should feel well balanced when held and their bristles should be
packed tightly and tapered up to the centre of the brush.
Brushes with nylon or polyester bristles are the best choice
since they hold their shape and maintain the proper stiffness
regardless of the amount of water they are exposed to. Natural
bristles will swell as they absorb water from the paint and will not
apply the paint evenly.
When using oil based paints, brushes made with synthetic
materials or natural fibres can be used.
Brushes should be dampened prior to painting. Water can
be used water for acrylic paints and paint thinner for oil or alkyd
paints.
For extra protection the painter should use safety glasses,
goggles or a face shield and a dust-mask and gloves are
recommended for sanding and scraping.
A NUMBER OF IMPORTANT FACTORS need to be considered
when selecting an appropriate defoamer for any aqueous coating
that is under development or reformulation. Perhaps the most
important questions to be answered are:
Careful preparation for a safe paint job
• What are the final requirements regarding defoaming
performance?
• What shear forces are available for the incorporation of the
defoamer?
• What is the contribution of the defoamer to the final costs of
the formulation?
• Do any side effects occur or are there any problems possible
when using the selected defoamer?
Preparation is the key to any successful paint job and this applies
to safety too. It is important that the painter makes sure he has
sufficient time to complete a job so he doesn’t have to rush it
to finish it, because this is exactly when careless mistakes and
accidents occur. The painter must make sure he takes regular
breaks during the paint job too - there is no point being tired on
top of a ladder.
Speaking of the ladder, the painter should make sure it’s in
good condition and check the shoulders between the rails. The
Golden Rule here is to always support the ladder at four stable
points.
Now to the paint
The selection of paint may seem like an easy decision requiring
nothing more than appropriate colour choice and a quick cost
comparison. However, the proper way to choose an interior paint
involves more than colour preference and price.
The Paint Quality Institute urges consumers to invest in a
quality paint. Quality paints made with pure acrylics invariably
offers excellent all round performance. These paints ensure extra
years of service, maintain an outstanding appearance and even
help ward off some common problems that can render a paint job
unsightly in a relatively short time period.
This investment will ensure long term cost savings. It means
less frequent painting and also guarantees a long, lasting top
quality finish.
Top quality pure acrylic paints offer a range of performance
advantages – they enable easy stain removal from the painted
surface and can withstand repeated washing or scrubbing, without
eroding or wearing through.
Pure acrylic paints are water-based, give off little odour and allow
quick re-entry into newly painted rooms. They also dry fast and can
be cleaned up easily with soapy water. If solvent based products are
chosen – and these include oil based paints, solvent based primers,
paint thinners and white spirits - they do need to be used and stored
with extra care. It is important to dispose of the used rags properly
as they can ignite spontaneously if not spread out to dry.
2 Gold Star Award • 3 Crayvallac® Surface Modifiers
4 Paint Advice • 5 Syloid® Matting Inks • 6 Paint Safety
Defoamer Selection for Aqueous Systems
mineral oil defoamers are: separation tendency during storage
in the paint, gloss reduction, a negative contribution to VOC,
reduced dirt-pick up resistance and occasionally negative impact
on colorant acceptance.
BYK-Chemie has several aqueous mineral oil defoamers, the
most popular are BYK-037 (our workhorse for flat latex paints)
and BYK-038 (suitable from lower to higher gloss latex paints).
These defoamers are especially recommended for those paint
manufacturers who want to use just one defoamer for many
different grades of latex paints from lower to higher PVC.
Silicone defoamers
Once very seldomly used in aqueous paints, today these defoamers
are already very popular in all kinds of aqueous systems, from
high PVC latex paints to high gloss emulsion paints, clearcoats and
industrial aqueous coatings. Many different grades are available
for each area and quality requirement. Chemically all silicone
defoamers are polyether modified dimethyl polysiloxanes (Fig.2)
with a well designed balance of compatibility and incompatibility.
EO polyether chains make the products more compatible, PO
polyether chains and longer dimethylsilicone blocks more
incompatible. In this way a wide range of defoaming properties
can be adjusted.
Figure 1: Incorporation factors of defoamers
Figure 1 deals with the practical considerations from the point
of view of the incorporation. Assuming that an appropriate
defoamer has been selected for the system to be defoamed (tick
mark on circle), the other factors such as dosage level, point of
addition during manufacturing, the duration and the shear forces
of the incorporation need to be optimized.
Not ‘whatever the weather’
Ideally, exterior painting should be undertaken when there is
little or no wind. Painting in direct sunlight should be avoided
as this can cause the water in paint to quickly evaporate before
the paint binder particles can completely fuse into a continuous,
highly durable film. This leads to early paint failures like peeling
and flaking. Oil-based paints must be applied to thoroughly dry
surfaces.
For interior painting, the painter should open the windows to
make sure there is good ventilation.
By carefully adhering to these critical factors in painting, perfect
results will be achieved.
Go to www.paintquality.co.za for invaluable advice on the latest paint trends.
Today the following defoamer classes are available to select
from:
CDP GRAPHICS
5
VOL 25 • MARCH 2007
Mineral oil based products
The most “conventional” of all aqueous defoamers, they are
mainly used on lower cost, higher PVC latex paints where they
provide a reasonable level of defoaming. Due to the higher mineral
oil price their significant cost benefit over silicones is today much
less that it was a few years ago. The major disadvantages of the
Figure 2: Chemical structure of silicone defoamers
Silicone defoamers have no drawbacks regarding gloss
reduction or dirt pick-up behaviour, but they need a well planned
incorporation (a certain speed for a certain time) to provide
the necessary defoaming without cratering. The probably only
disadvantage of the silicones is that they don´t perform very well
under extreme pH conditions (pH above 9.5-10) due to a slow
chemical decomposition.
BYK-Chemie has currently 20 different aqueous silicone
CONT’D ON PG 2
4
3
2
www.paintquality.co.za
CONT’D ON PG 2
Defoamer Selection for Aqueous Systems
defoamer products, from which the most important are
BYK-022 (for medium to high gloss latex paints),
BYK-024 and BYK-028 (for clearcoats, and as a letdown
defoamer for high gloss latex paints) and BYK-1615 (for
high PVC latex paints).
The latest silicone defoamer generation (e.g BYK-1730)
can be used even in the very critical low VOC aqueous
paints formulations. Another new product, BYK-093 has
been developed for those critical systems (wood varnishes,
two-pack aqueous polyurethanes) where “normal”
defoamers loose their defoaming performance during the
storage of the paint.
BYK-017
Shear forces
BYK-044
Grinding
BYK-021
BYK-022
BYK-019
BYK-018
BYK-023
Let Down
BYK-024
BYK-094
BYK-028
Post
Addition
re
Mo
co
mp
i
re
Mo
nc
pa
om
le
tib
ble
ati
BYK-025
Time of incorporation
Figure 3: Selection chart for silicone defoamers
Fig. 3 gives an overview on the most typical silicone
defoamers regarding their incorporation conditions (speed,
duration). The most powerful products (but also the most
critical regarding cratering risk) are BYK-017, BYK-018 and
BYK-019. Defoamers with the best compatibility are BYK028 and BYK-025. This chart allows a systematic selection
of the right defoamer for almost every coating application.
Polymeric defoamers
A new class of defoamers, based on special incompatible
polymers, opens new perspectives for aqueous systems.
These defoamers are chemically stable even at very high pH
values (pH 12), and provide a good alternative to silicones
and mineral oil based products.
BYK-011 is a special polymeric defoamer formulation
which needs relatively high dosage levels (up to 2 %), but
provides excellent compatibility and defoaming in special
systems like aqueous two-pack polyurethanes or alkyd
emulsions.
BYK-012 is mainly used in medium and higher PVC
(above 35 %) architectural latex paints as a very powerful
alternative to mineral oil defoamers. Its main advantage
is the excellent defoaming performance at lowest dosage
levels, as little as
0.05 to 0.1 %, together with very good hydrolitic stability
at high pH and no negative influence on VOC, colorant
acceptance and dirt pick-up.
Please contact the local BYK-Chemie representative for
further information.
New Germany Site
Attains Gold Star
Award for Corporate
Social Responsibility
AT A GLITTERING GALA DINNER on the eve of Thanksgiving,
Rohm and Haas South Africa were awarded the American
Chamber of Commerce Gold Star Award 2006 for community
development and welfare.
This award is the highest
recognition in the category of corporate social responsibility
for American companies operating in South Africa.
This Community Development Award is presented to
companies who demonstrate a valuable involvement and
commitment to their local community, assisting these
communities to become sustainable.
Rohm and Haas South Africa has worked with the Imbumba
community in Ixopo for the past 3 years and the families in this
region have attained great rewards from egg, vegetable and
milk production. The project has aptly been named “Passing
on the Gift” as the families in Ixopo have to pass on goats and
chickens to other families within the community.
In August 2005, 15 members of the project each received
2 Saanen dairy goats and in August this year 15 goats were
passed on to 15 new members of the Ixopo initiative. 25 egg
laying hens will also be passed on before the end of 2006.
With limited resources, it is great to see such generous
rewards for the community.
Seen here with the American Ambassador from left
to right: Dr James Mooney, Ambassador Eric Bost,
Nita Jacob, Dev Moodley, Roberto Bona and Tendai
Chingonzoh
CRAYVALLAC® Surface Modifiers
CRAY VALLEY has been manufacturing the
CRAYVALLAC ® range of surface modifiers for more
than 40 years. These products are stocked and sold
in over 100 countries around the world and is being
introduced to the South African market.
These products complement the basket of products
already available to the Coatings and Allied
industries, through CRAY VALLEY and Servochem
CRAYVALLAC®
Industrial
Coatings
Wood
Varnishes /
Decorative
Coatings
PC
WF 1039
x
x
WW 1074
WW 1077
x
Depending on application, these high performance
products provide
WN 1495
x
x
WN 1875
x
x
WS 1147
x
x
x
x
x
x
x
x
x
x
WN 1265
•
•
•
•
•
•
•
WaterBased
Coatings
x
WN 1135
Slip and scratch resistance
Mar, rub and abrasion resistance
Solvent & Stain resistance and water
repellence
Block resistance
Gloss and matt control
Flow and Levelling
Anti-blocking
Heat resistance
Enhanced sandability
UV resistance
Powder
Coatings
x
WW 1001
These surface modifiers are mainly based on
polyethylene, polypropylene and PTFE.
•
•
•
Inks
APPLICATIONS:
x
x
WN 2000
x
x
WN 3025
x
WF 3200
x
x
x
x
WS 4700
x
x
x
WF 6010
x
x
WS 8050
x
x
WS 8200
x
WF 9200
x
x
WN 9500
WF 9710
x
x
PRODUCTION DESCRIPTION
Crayvallac PC:
Micronised degassing, flow and levelling
Crayvallac WW 1001:
Water based polyethylene wax dispersion for scratch and slip
Crayvallac WF 1039:
Micronised PTFE based for slip, mar and texturing
Crayvallac WW 1074:
Oxidised polyethylene dispersion for control of lubricity
Crayvallac WW 1077:
PTFE modified polyethylene dispersion for surface protection
Crayvallac WN 1135:
Extremely tough polypropylene wax for soft-touch, lubricity and matting
Crayvallac WS 1147:
Isopropanol based polyethylene wax dispersion with PTFE for lubricity and enhanced heat resistance
Crayvallac WN 1265:
Thermally stable micronised amide wax for improved sandability in wood primers and sealers
Crayvallac WN 1495:
Micronised polyethylene wax for scratch and slip
Crayvallac WN 1875:
Micronised plastic for matting
Crayvallac WN 2000:
Micronised polyethylene wax for heat and solvent resistance
Crayvallac WN 3025:
Micronised polyethylene for scratch, slip and solvent resistance
Crayvallac WF 3200:
Micronised polyethylene with PTFE for surface lubricity
Crayvallac WS 4700:
Isopropanol based polyethylene wax dispersion for surface lubricity
Crayvallac WF 6010:
Micronised polyethylene with PTFE for surface lubricity and heat resistance
Crayvallac WS 8050:
Butyl Acetate based polyethylene wax dispersion for surface lubricity
Crayvallac WS 8200:
Butyl Acetate based polyethylene wax dispersion with PTFE for surface lubricity and heat resistance
Crayvallac WF 9200:
Micronised oxidised polyethylene wax with PTFE for surface lubricity, heat resistance and water compatibility
Crayvallac WN 9500:
Modified polypropylene dispersion for matting, improved mar & rub resistance
Crayvallac WF 9710:
Micronised polyethylene wax with a high PTFE modification level for enhanced slip and heat resistance
Technical and Safety Data sheets are available on our website www.crayvallac.com or, contact your local Servochem representative
or CRAY VALLEY South Africa direct, for further details.
THE ROHM AND HAAS Paint Quality Institute (PQI) has re-vamped its
South African website (www.paintquality.co.za) to provide the local paint
market with even more relevant information on the advantages of using
high quality paint and the importance of its correct application.
This easy-to-navigate website offers a wealth of practical advice to both
the novice and the DIY enthusiast. The educational site provides up-to-date
information on what constitutes a quality paint, new paint technology, as
well as the latest techniques and trends. There is also a section on the benefits
of using acrylic paints. The PQI also includes helpful tips on choosing colour
and decorative paint effects.
User-friendly features include step by step instructions on how to create
a good paint finish, a cause and solution section for painting problems and
an onscreen calculator to help work out how much paint is required for each
job. An encyclopaedia has also been included to explain terminology that is
used by manufacturers when describing techniques and ingredients.
“The PQI, which is a brand neutral organisation, encourages improvement
of quality standards in the coatings industry and aims to provide the
consumer with better value for money,” says Nita Jacob, spokesperson for the
Rohm and Haas Paint Quality Institute. “This programme, which involves
close co-operation between the PQI, paint manufacturers, professional
painters and contractors, as well as retailers, brings insight and knowledge
about paint and its valuable role in protection and decoration. Improved
quality and safety standards, as well as responsible care for health and the
environment are also encouraged.
“It is heartening to now see the competitive focus on performance
improvements and the introduction of new, innovative coatings in this
country. Old products are being improved and new technologies are
opening doors to fresh concepts.”
The PQI has recently transformed the look and feel of its global logo
to reflect its expanded colour and design competence, as well as its multinational presence.
The Paint Quality Institute, which originated in the USA in 1989 and now
operates successfully in over 14 countries, strives to create a more informed
paint consumer and assists quality paint manufacturers in their efforts to
produce and promote quality paints.
For help, advice and inspiration go to
www.paintquality.co.za