APPLICATION INFORMATIONNEW GENERATION CLAY TECHNOLOGY FOR EFFICIENTPOLYOLEFIN REINFORCEMENT
TP-A 402

New generation clay technology for efficient polyolefin reinforcement

Contents
03 The challenge
04 The solution – BYK-MAX CT 4270
05 Reduced density
06 Increased scratch resistance
08 Improved processability
08 Conclusion

03

The challenge
To access a broad range of applications from TPO bumpers andinterior/exterior automotive trim to many other durable goods,
polypropylene (PP) needs reinforcement. Talc is often used toprovide reinforcement because it is a low-cost option.
However, as a mineral, talc has a higher density, increasing thedensity of compounds and overall part mass. A­ dditionally, using
talc in PP compounds reduces both scratch resistance and design
flexibility (due to interference with the strength and appearanceof knit/weld lines).
While talc provides a low-cost reinforcement option, it does notenable decreased density and improved scratch resistance goals.

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New generation clay technology for efficient polyolefin reinforcement

The solution – BYK-MAX CT 4270
BYK-MAX CT 4270 is a controlled blend of specific gradesof clays (mixed ­morphology) that offers reduced density,increased scratch resistance and improved processability
without negatively affecting part cost. Whereas 12-18 % ofvarious grades of talc is required to meet desired physicalproperties, only 5 % of BYK-MAX CT 4270 is required. The
physical property benefits of clay reinforcement have beenrecognized for many years. However, clay has been more
expensive and has required the use of grafted PP additives
and special processing to manufacture compounds. These
have all increased the cost of using clay and prevented morewidespread acceptance. To counteract these, BYK developed
BYK-MAX CT 4270 using a proprietary blend of clays
to provide greatly increased exfoliation using standard
processing techniques. These factors combine to utilize
the benefits of clay with no increase in part cost.

BYK-MAX CT 4270 – Morphology improvement
Montmorillonite clay

BYK-MAX CT 4270

G. 01

BYK-MAX CT 4270
Product type
Organically modified clay
Application
TPO and PP compounds
Key benefits•R educed density/massreduction• Increased scratch resistance• Improved processability

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New generation clay technology for efficient polyolefin reinforcement

Reduced density
Density reduction is an important trend in the automotiveindustry. Reducing the weight of vehicles results in improved fuelconsumption, thus reducing the carbon dioxide emissions thatare driving global climate change. Additionally, mass reduction willremain a key to the range of electric vehicles.
In an internal BYK study, bumper grades using BYK-MAX CT 4270
were developed and compared to commonly available bumper
grades using talc. To match the properties of the 12 % talc
compound only 5 % of clay was required, resulting in a 7 %density reduction.

BYK-MAX CT 4270 – TPO development formulations
Parameter

GoalTalc 12 %control

5 % BYK-MAX CT 4270
Formulation A

Formulation B

Formulation C

Formulation D

Density

Minimize

0.986

0.923

0.920

0.923

0.918

Melt Flow Index

35+2723252123

Flexural Modulus (MPa)

1600+

1400

1600

1520

1241

1345

Izod Impact Strength 23 °C

5555

21233632

Izod Impact Strength -30 °C77.0

3.6

3.4

4.1

4.0

Dart Impact Strength 23 °C

264

264

280256264

264

Dart Impact Strength -30 °C

240 (DF)240 (DF)112 (BF)

152 (BF)

176 (DF)

216 (DF)HDT at 0.45 MPa–102.5

100.0

101.0

94.2

96.6

HDT at 1.8 MPa

≥ 50

53

55

56

54

56

DF: Ductile failure, BF: Brittle failure

T. 01

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New generation clay technology for efficient polyolefin reinforcement

Increased scratch resistance
Similar to automotive exterior, both weight and cost
reduction are key trends for interiors as well. In addition,
removal of coatings reduces cost and the environmental
impact of VOC during the coating application process. The
transition to PP based materials for interiors reduces cost,weight and emissions. However, this transition has been
hindered by the reduction in scratch resistance when using
talc reinforced PP. Substituting talc by BYK-MAX CT 4270
enables this transition without impair scratch resistance.

BYK-MAX CT 4270 – Scratch performance improvement
PP/talc: particles of about 10 micron
are observed on scratch line

PP/BYK-MAX CT 4270:
less whitening observed

As can be seen in the example on the right, talc particles inthe walls of the scratch are very visible and reflect more lightmaking the scratches more visible than neat polymer.
BYK-MAX CT 4270 does not produce the same effect due
to its finer dispersion.
The Erichsen Five Finger Scratch test is commonly used toevaluate the scratch resistance of polymer surfaces. This
test uses fingers with different loads to ­create scratches inthe surface which are then evaluated using the lightness
scale from a spectrophotometer. The greater the change inlightness from the unscratched to the scratched area, themore visible the scratch. The data below demonstrates howa system using B­ YK-MAX CT 4270 dramatically outperforms
systems using talc.

G. 02

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New generation clay technology for efficient polyolefin reinforcement / Increased scratch resistance

BYK-MAX CT 4270 – Scratch test improvement
BYK-MAX CT 4270 5 %Talc 6 µm 18 %Talc 1 µm 18 %G. 03

BYK-MAX CT 4270 – Scratch test data
Change in brightness

BYK-MAX CT 4270 5 %Talc 6 µm 18 %Talc 1 µm 18 %∆L 5 N force

0.0

1.2

1.2

∆L 7 N force

0.2

1.9

1.6

∆L 10 N force

0.3

2.6

2.2

∆L 15 N force

0.5

4.1

4.1
T. 02

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New generation clay technology for efficient polyolefin reinforcement

Improved processability
The processability of a material can enable molding
thinner parts at ­shorter cycle times. This provides weightand cost savings. To enable this, a material must flow
easily and set up quickly. The use of BYK-MAX CT 4270
as a reinforcement results in a material that flows moreeasily under injection molding pressure and enables
lower molding temperatures. These lower temperatures
shorten cycle times an average of 5 %.
Even though mold temperatures were decreased asshown in the table, max injection pressure was also
reduced 10 %.
BYK-MAX CT 4270
Door inner panel
development

BYK-MAX CT 4270 – Molding condition improvements
Material

PP/talc

PP/BYK-MAX CT 4270

Hot Runner

240 °C

220 °C

Nozzle240 °C

210 °C

Middle230 °C

205 °C

Rear

210 °C

200 °C
T. 03

Conclusion
BYK-MAX CT 4270 is an excellent reinforcing agent for PP
that doesn’t suffer the challenges of talc. Replacing talc withBYK-MAX CT 4270 offers advantages that are important tothe automotive industry including 7 % density reduction andimproved scratch resistance for unpainted surfaces while

maintaining other required physical properties.
BYK-MAX CT 4270 provides these benefits at equivalent
formula costs and additional savings through cycle time
reduction enabled by lower molding temperatures.

11/2021
TP-A 4BYK-Chemie GmbH
P.O. Box 10 02 4546462 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®,BYK®-MAX®, BYK®-SILCLEAN®, BYKANOL®, BYKETOL®, BYKJET®, BYKO2BLOCK®, BYKOPLAST®, BYKUMEN®, CARBOBYK®, CERACOL®, CERAFAK®,CERAFLOUR®, CERAMAT®, CERATIX®, CLAYTONE®, CLOISITE®, DISPERBYK®, DISPERPLAST®, FULACOLOR®, FULCAT®, GARAMITE®, GELWHITE®,
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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
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