Advantages Of Copolymer Waxes In Masterbatches

Containing Carbon Black And Other Polar Pigments

A. Uner, O. Reich

1

2

Waxes in masterbatch

Waxes are used in masterbatch to disperse pigments or additives

consistent coloration with high color strength

Waxes enhance process reliability and reduce cost through less downtime

high masterbatch flowability

high output during manufacturing of MB

prevent fiber cracking during spinning

Waxes provide release effect on hot metal surface and improve surface

properties, such as

gloss

smoothness

hydrophobicity

3

Typical choices

PE Homopolymers

nonpolar

different degrees of branching

broadly applicable, good “all-rounder”

different melt viscosities

Micronized

spherical or irregular particles available

very low agglomeration (spherical particles)

fast and efficient distribution, rapid melting (fast)

Copolymers

typically ethylene/vinyl acetate copolymers, more polar then PE

high performance waxes especially with polar pigments like Carbon Black

Polarity of pigments

Organic pigments generally not very polar, but still noticeably different:

4

5

Polarity of pigment and the wax

Dispersing with non-polar homopolymer wax

Luwax® A, Luwax® AL 3, Luwax® AF 32

wetting of pigment particle by adhesion

suitable for variety of pigments

Dispersing with polar ethylene copolymer wax

Luwax® EVA 3

polar groups coordinate on the pigment

particle surface

more efficient wetting of the pigment

primary pigment

particle

PE wax

PE wax with

functional group

primary pigment

particle

Dispersing mechanism

® = Registered trademark of BASF in many countries

6

Benefit of better dispersing

An alternative wax can disperse better under the same conditions and

increase the color strength

or …

use of a better wax maintains the same color strength with less pigment

reduce the production cost of the masterbatch

additionally

a more effective wax facilitates the production of

highly concentrated masterbatches

7

Wax evaluation: methods

Performance of waxes can be investigated with various test programs:

preparation of masterbatch in extrusion process

measurement of back pressure value (filter test)

color strength evaluation, 1:10 white dilution, 5 % titanium dioxide

8

Twin Screw Extruder

9

Measurement of Back Pressure Values

Transportation unit Filter unit

Zone 1 Zone 2 Zone 3 Zone 1 Zone 2 Zone 3

160 280 280 285 285 285

1 Extruder

2 Melt pump

3 Filter pressure sensor

4 Sieve with plate

10

Back pressure value is used to compare the

dispersion performance of different waxes

0

5

10

15

20

25

30

35

0 20 40 60

time [min]

pressure [bar]

wax 1

wax 2

pmax1

pmax2

11

Example: Carbon Black

Luwax® EVA 3 (filter back pressure)

0

1

2

3

4

5

6

7

8

without wax Luwax® A Luwax® EVA 3

Masterbatch formulation:

25 parts Carbon Black (Printex 60)

65 parts LD-polyethylene

10 parts wax

back pressure value [daN/g]

12

Carbon Black agglomerates

without wax

Reduced number and size of

Carbon Black agglomerates

with Luwax EVA 3

Microscopic pictures:

Example: Carbon Black

Luwax® EVA 3 (extrusion results)

13

Example: Carbon Black

Luwax® EVA 3 (color strength)

Formulation:

25 parts Carbon Black (Printex 60) Extension 1:20

65 parts LD polyethylene (Lupolen 1800 S)

10 parts wax

Luwax A

color strength = 100 %

Luwax EVA 3

color strength = 120 %

High concentration masterbatches

Non-polar Luwax® A: back pressure increases at high pigment concentration

Polar Luwax® EVA 3: high pigment concentrations achievable without increasing

back pressure; outperformed benchmark14

5.3

6.3

5.2

6.4

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

40% Pigm. 50% Pigm. 50% Pigm. 50% Pigm.

Back pressure value [daN/g]40% versus 50% Carbon Black, 10% wax

Lu

wax

®A

Lu

wa

x®

A

Lu

wax

®E

VA

3

Ben

ch

mark

EV

A c

op

ol.

80.0

90.0

100.0

110.0

120.0

130.0

P.R. 57.1 P.V. 23 P.Bk. 7

Luwax® A

Luwax® EVA 3

15

Results – color strength

Luwax® EVA 3 especially superior with polar Carbon Black and PRE57.1

16

Example: Pigment Blue 15:3

Comparison of different wax technologies

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

Luwax® A Luwax® EVA 3 PE degradationwax

FT wax

Back pressure value (daN/g)Masterbatch recipe

30 parts Pigment Blue 15:3

55 parts LDPE MFI 20

15 parts wax

0

20

40

60

80

100

120

Luwax® A Luwax® EVA 3 PE Degradationwax

FT wax

Relative color strength (%)

color strength measurement

of specimen obtained by

addition of Lupolen 1800 S

affording a pigment

concentration of 4 %

17

Adjustment of the parameters

co

lor

str

en

gth

shear force

operating

shear force

maximum color strength

specification

18

Adjustment of the parameters

co

lor

str

en

gth

shear force

specification

operating

shear force

maximum color strength

19

Adjustment of the parameters

co

lor

str

en

gth

shear force

specification

operating

shear force

maximum color strength

20

Adjustment of the parameters

co

lor

str

en

gth

shear force

specification

operating

shear force

maximum color strength

pigment conc. X

pigment conc. Y

21

Summary: wax selection

Luwax® EVA 3 is a very efficient dispersing agent for polar pigments,

e.g. Carbon Black, Pigment Red 57.1 (“lake pigments”).

Luwax® EVA 3 disperses Carbon Black and polar pigments very

efficiently due to its pronounced polarity and thus better wetting properties.

For non-polar pigments homopolymers such as Luwax® A are common.

For special purposes Luwax® A can be replaced by other homopolymers:

Luwax® AL 3 (lower melt viscosity)

Luwax® AF 32 (micronized; faster mixing and homogenization).

The best wax choice has to be established on the individual equipment

with individual formulation.

22

General guidelines

Pigments Waxes Polyethylene waxes

Micronized

polyethylene

wax

Ethylene

Copolymer

Quantity Quantity Luwax® A Luwax® AL 3 Luwax® AF 32 Luwax® EVA 3

Organic pigments 30 – 40 % Approx. 10 %

Inorganic

pigments30 – 50 % Approx. 6 – 8 %

Carbon black 30 – 40 % Approx. 15 %

Titandioxide,

chalk, Barium

sulfate

40 – 70 % Approx. 5 %

Additives

Antioxidants 40 – 70 % Approx. 8 %

UV-stabilizers 30 – 50 % Approx. 15 %

Blowing agents 30 – 40 % Approx. 30 %

23

Influence of the plastic type

PE waxes can be used in all kind of plastics.

The type of plastic has very low influence on the dispersing effect.

The interaction between pigment or additive and wax determines the quality of the

dispersion.

PVC PE PP PA POM PS ABS ASA PET EVA PIB SBR PC

Luwax® A

Luwax® AL 3

Luwax® EVA 3

DISCLAIMER

24® = Registered trademark of BASF in many countries

This document, or any answers or information provided herein by BASF, does not constitute a legally binding obligation of BASF. While the descriptions, designs, data and information contained herein are presented in good faith and believed to be accurate, they are provided for your guidance only. Because many factors may affect processing or application/use, we recommend that you make tests to determine the suitability of a product for your particular purpose prior to use. It does not relieve our customers of the obligation to perform a full inspection of the products upon delivery or any other obligation. The claims and supporting data provided in this publication have not been evaluated for compliance with any jurisdiction’s regulatory requirements and the results reported may not be generally true under other conditions or in other matrices. Users must evaluate what claims and information are appropriate and comply with a jurisdiction’s regulatory requirements. NO WARRANTIES OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, ARE MADE REGARDING PRODUCTS DESCRIBED OR DESIGNS, DATA OR INFORMATION SET FORTH, OR THAT THE PRODUCTS, DESIGNS, DATA, OR INFORMATION MAY BE USED WITHOUT INFRINGING THE INTELLECTUAL PROPERTY RIGHTS OF OTHERS. IN NO CASE SHALL THE DESCRIPTIONS, INFORMATION, DATA, OR DESIGNS PROVIDED BE CONSIDERED A PART OF OUR TERM SAND CONDITIONS OF SALE.

Safety

We know of no ill effects that could have resulted from using our products for the purpose for which they are intended and from processing them in accordance with current practice. According to the experience we have gained up to now and other information available at our disposal, our products do not exert any harmful effects on health, provided that they are used properly, due attention is given to the precautions necessary for handling chemicals, and the information and advice given in our safety data sheet are observed.

Labelling

Details about the classification and labelling of our products and further advice on safe handling are contained in the current safety data sheets.