Rohm and Haas


PARALOID™ K120N-K120ND Acrylic Processing Aid
The Industry Standard for Controlled Fusion, Optimum Processing and Product Quality

Description

Over 35 years ago, Dow introduced the first all-acrylic processing aid, pioneering a technological breakthrough. This addition has made rigid PVC processing possible, and therefore a viable material for many new applications.

Today, PARALOID K120N and K120ND are industry standards, used in the production of bottles, in film/sheet applications and in the construction industry, representing a high proportion of the total sales of the world’s acrylic processing aids for vinyls.

In addition to faster fusion, PARALOID acrylic processing aids offer many attractive rheological features and improve the quality and finish of the product. These benefits will be evident from the results of the tests shown in this brochure.

By dramatically shortening the fusion time, PARALOID K120N and K120ND can increase production output and improve yield.

Improved fusion also permits a broader range of processing temperatures and conditions. Other processing benefits include improved melt-elasticity and reduction of plate-out and melt fracture.

PARALOID acrylic processing aids improve product quality in terms of surface gloss and finish, more even thickness and weight, weld-line strength, tensile strength and impact efficiency.

These benefits are obtained with the use of both PARALOID K120N and K120ND. In addition, PARALOID K120N and K120ND comply with the FDA and most European food packaging regulations.* PARALOID K120ND is generally chosen by manufacturers requiring excellent dispersibility and good optical properties, under low-shear processing conditions.

The PARALOID K120N/K120ND production process has obtained the ISO 9002 quality assurance certification.

Performance in Processing

Using a PARALOID processing aid to change the polymer melt rheology provides the processors with a material that adapts to wide operational conditions and allows increased throughput. The addition of these products to PVC formulations improves the fusion behaviour and results in a more homogeneous melt. The high molecular weight of the processing aids also results in higher melt strength and higher rupture stress.

Fusion

PARALOID processing aids give a significant improvement to fusion, with faster fusion speed and higher fusion torque.

Brabender Rheology Test (Sn-Stabilised)

This test shows the effect of changing rotor speed on rheology, with a bowl temperature of 150°C.

Without Processing Aid K120ND, 1 phr

20 RPM

40 RPM

60 RPM

20 RPM

40 RPM

60 RPM

Fusion time (s)

518

138

36

296

78

30

Fusion torque (Nm)

60.7

68.1

78.6

66.4

75.7

78.4

Fusion temperature (°C)

162

160

156

164

161

156

Equilibrium torque (Nm)

40.6

32.9

29.1

41.0

35.0

29.7

Sn Formulation

S PVC K60

100

Sn mercaptide stabiliser

1.4

Glycerol mono-oleate

1.0

High molecular weight complex ester

0.6

This test shows the effect of changing bowl temperature on rheology, with a rotor speed of 40 RPM.

Without Processing Aid K120ND, 1 phr

 

140°C

150°C

160°C

140°C

150°C

160°C

Fusion time (s)

260

138

66

178

78

54

Fusion torque (Nm)

70.5

68.1

75.3

68.3

75.7

80

Fusion temperature (°C)

159

160

163

165

161

161

Equilibrium torque (Nm)

39.2

32.9

27.9

39.7

35.0

28.7

Brabender Rheology Test (Pb-Stabilised)

Similar results are found in Pb-stabilised formulations.

 

Without
Processing Aid

K120N, 1 phr

K120N, 2 phr

Fusion time (s)

82

68

50

Fusion torque (Nm)

54.6

58.5

65.6

Fusion temperature (°C)

166

166

164

Equilibrium torque (Nm)

32.5

33.0

34.0

Pb Formulation

S PVC K57

100

Tri-basic Pb sulphate

4

Tri-basic Pb stearate

0.25

N Pb stearate

0.15

Calcium stearate

0.75

Partially esterified wax of montanic
acid saponified with calcium

0.20

High molecular weight paraffin wax

0.15

CaCO3

5.00

Pigment

0.01

PARALOID K120N processing aid

as indicated

Melt Strength and Homogenisation

The marked increases in melt strength and homogenisation provided by the addition of PARALOID K120N and K120ND translate into reduced melt fracture and more detailed thermoforming, giving deeper draws without tearing.

Rheotens Melt Elongational Test (Sn-Stabilised)

The addition of PARALOID processing aids significantly improves the elongational properties, resulting in better thermoforming and blow moulding. The increased stress at break translates into reduced melt fracture and improved surface finish.

The Rheotens test, which measures elongation and stress of polymer melts, characterises melt elastic properties directly from the extruder, and predicts the performance of compounds in the molten state.

 

Without
Processing Aid

K120N, 2 phr

K120ND, 2 phr

Elongation (%)

450

710

770

Die swell (%)

1.5

1.8

1.8

Stress at break (N/mm2)

5.0

8.8

9.7

Sn Formulation

S PVC K57

100

Sn mercaptide stabiliser

1.5

Glycerine tri ester

1.0

Ester of montanic wax acid with
Dihydric alcohol

0.4

Ester of montanic wax partially
saponified with calcium

1.0

PARALOID BTA 736

10.0

PARALOID processing aid

as indicated

Parison Extrusion Tests

These tests, on Ca/Zn and Sn formulations, show the effect of PARALOID processing aids on flow time and weight, which translates into better control of wall thickness.

Sn-Stabiliser

 

Total Weight (g)

Flow Time (s)

Relative Die-Swell

Without processing aid

93.96

23.4

*

K120N, 0.25 phr

92.01

23.1

1.00

10.50 phr

95.13

24.0

1.03

K120N, 0.75 phr

95.89

24.3

1.06

K120N, 1.00 phr

99.14

25.2

1.09

K120N, 1.50 phr

103.89

26.1

1.14

K120ND, 0.25 phr

93.59

23.4

1.02

K120ND, 0.50 phr

96.34

24.0

1.08

K120ND, 0.75 phr

100.50

25.2

1.10

K120ND, 1.00 phr

105.50

26.4

1.16

K120ND, 1.50 phr

113.16

28.2

1.23

Sn Formulation

S PVC K57

100

Octyl-Sn mercaptide stabiliser

1.5

Fatty acid of polyol

0.5

Epoxidised soya bean oil

0.25

Ester of montanic wax partially
saponified with calcium

0.25

Ca/Zn-Stabilised

 

Total Weight (g)

Flow Time (s)

Bottle Weight (g)

Without processing aid

105.0

22.0

39.1

K120N, 0.2 phr

106.3

23.5

39.6

K120N, 0.5 phr

107.6

24.0

40.3

K120ND, 0.2 phr

108.2

24.0

40.3

K120ND, 0.5 phr

111.7

25.0

41.8

Ca/Zn Formulation

S PVC K57

100

Calcium hydroxy stearate

0.3

Zn octoate 23%

0.085

Epoxidised soya bean oil

5.75

Ester of montanic wax partially
saponified with calcium

0.75

Stearoyl Benzoyl methane

0.20

Glycerine tri ester

1.5

Polar PE wax

0.15

PARALOID BTA 736-S

6.0

 

Ca/Zn Formulation

S PVC K57

100

Calcium hydroxy stearate

0.3

Zn octoate 23% Zn

0.085

Epoxidised soya bean oil

5.75

Ester of montanic wax partially
saponified with calcium

0.75

Stearoyl Benzoyl methane

0.20

Glycerine tri ester

1.5

Polar PE wax

0.15

PARALOID BTA 736-S

6.0

Heat Stability

The addition of PARALOID K120N and K120ND processing aids does not adversely affect heat stability.

Dynamic Heat Stability (Ca/Zn-Stabilised)

Typical Powder Properties

 

K120N

K120ND

Bulk density aerated (g/cm3)

0.408

0.452

Bulk density packed (g/cm3)

0.491

0.541

Powder flowability,
through 5-mm funnel (s)

10.9

9.4

Fines level, 325 mesh (%)

12.9

11.2

Performance in Finished Products

PARALOID processing aids, in addition to enhancing the performance of processing, give a clear benefit to the finished products. Through good dispersion, the processing aid improves the surface quality without affecting organoleptic properties.

By insuring good fusion and the homogenisation of other additives, the addition of PARALOID processing aids will optimise the physical properties of the finished product.

Surface Quality

The addition of a PARALOID processing aid improves manufacturing production and gives a finished product the high gloss and excellent surface quality required.

Melt Fracture

Melt fracture, which is related to the compound formulation and to the shear stress, shear rate, and temperature of processing, limits manufacturing production rates and can reduce the quality of the finished product.

The photographs below show how PARALOID K120ND reduces the melt fracture of extruded rods, greatly improving the surface quality.

Clarity Test

Because PARALOID processing aids are fully compatible with PVC, they do not affect the optical properties. In critical applications, K120ND is generally chosen for its superior performance.

 

K120N, 1.0 phr

K120ND, 1.0 phr

LT (%)

92.0

92.7

Haze (%)

3.2

2.8

Yellowness index

3.3

3.1

Ca/Zn Formulation

S PVC K57

100

Calcium hydroxy stearate

0.3

Zn octoate

0.078

Epoxidised soya bean oil

5.75

Ester of montanic wax partially
saponified with calcium

0.75

Stearoyl Benzoyl methane

0.20

Glycerine tri ester

1.5

Polar PE wax

0.15

PARALOID BTA 736-S

6.0

Dispersion

PARALOID K120N and K120ND processing aids help dispersion of compounding additives, and do not contribute to gel formation. For critical applications, K120ND has an especially good rating.

Inflated Parison Test (Sn-Stabilised)

Dispersion Rating

 

Low Shear

High Shear

K120N

8

4

K120ND

3

1

Sn Formulation

S PVC K58

100

Sn mercaptide stabiliser

1.5

Fatty acid of polyol

0.5

Epoxidised soya bean oil

0.25

Ester of montanic wax partially
saponified with calcium

0.25

Dioctyl phthalate

5.0

Organoleptic Properties
(Ca/Zn-Stabilised)

PARALOID K120N and K120ND processing aids used in Ca/Zn-stabilised formulations for food products, such as water bottles, have a negligible effect on taste. In the following test, bottles made with a formulation including the PARALOID processing aids are filled with mineral water, which is then compared to the same mineral water in glass bottles.

Dimensional Control

The addition of PARALOID K120N processing aid gives better control of wall thickness in extruded profile and pipe. This better control increases efficiency and output, and thereby reduces production costs.

The results in the following tables were obtained from one-month extended trials producing large pipes of various diameters and wall thicknesses.

Wall Thickness Variations

 

Without
Processing Aid

K120N, 0.4 phr

K120ND, 0.8 phr

Wall thickness variation (%)

8.5

6.72

2.62

Wall thickness range (%)

15.32

12.25

5.11

Variation from nominal thickness (%)

12.38

8.41

3.42

Wall Thickness and Output Variations

 

Without
Processing Aid

K120N, 0.8 phr

Pipe Production, Wall Thickness

Minimum - maximum (mm)

5.15 to 5.50

4.27 to 4.50

Range (mm)

0.35

0.23

Thickness variation (%)

3.38

2.62

Variation from nominal thickness (%)

20.9

3.42

Pipe Output

Metres/hour

68.5

68.5

Kg/hour

558.1

498.5

Pipe Weight

Kg/metre - measured

8.05

7.09

Standards and Formulations

Test Standards and Descriptions

Test

Standard

Optical

ASTM-D1003-61

Yellowness index

ASTM-D1925-70

Inflated Parison Test

In this test, the parison is extruded vertically from the Bekum die to the floor. The hot parison is then squeezed between two vertical plates and allowed to cool. The cold parison is removed from between the plates and cut carefully into 10-cm segments. Each segment is weighed and plotted against the parison length. The segment weights are plotted back to the zero length, to give the weight/cm of the first part of the parison exiting the Bekum die.

The die swell is calculated as the ratio of the zero-length weight of the parison with processing aid to the zero-length weight of the parison without processing aid.

Rheotens Extensiometer

The Rheotens Extensiometer is an instrument designed to measure elongation and stress of polymer melts. The Rheotens Extensiometer is comprised of an extrusion gear assembly, a programmer, and a chart recorder.

The programmer is used to control the speed and acceleration of two cogged wheels in the extrusion gear assembly. The polymer melt strand is passed between the two cogged wheels, and the chart recorder records the force and velocity.

The operator first sets the speed and acceleration, typically to the same linear speed as the extrudate, and then places the polymer melt strand between the two cogged wheels. The speed is then increased, and the resulting elongation and stress can be charted.

Recommended Formulations

Corrugated Land Drainage Pipe

S PVC K67

100.0

Tri-basic Pb sulphate

1.00

Di-basic Pb stearate

1.25

Calcium stearate

1.00

Stearic/Palmatic acid

0.30

High molecular weight paraffin wax

0.20

Glycerol mono-stearate

0.40

CaCO3

8.00

Pigment

as required

PARALOID K120N processing aid

2 to 3

Calendered Film and Sheet

S PVC resin K60

100.0

PARALOID BTA 736-S

6.0

PARALOID K120N

1.0

PARALOID K175

1.0

Di-n Octyl-Sn mercaptide stabiliser

1.0

Glycerol mono-oleate

1.0

Ester of montanic acid with
ethylene glycol

0.4

Blue toner

0.006

Violet toner

0.011

Cosmetics and Toiletries Bottle

S PVC resin K57

100.0

PARALOID BTA 736-S

7.0

PARALOID K120N

1.2

PARALOID K175

0.6

Di-n Octyl-Sn mercaptide stabiliser

1.3

High molecular weight complex
fatty acid ester with calcium

0.4

Polar polyethylene wax

0.25

Tri glycerol ester of hydroxy
saturated fatty acid

1.2

Blue toner

0.006

Violet toner

0.01