Evaluation of Treated Aluminosilicate Microspheres in EPDM and Silicone ElastomersProcessing and Performance Effects Using Solid Microsphere Process Aids

Erick Sharp ACE Products and Consulting, LLC Uniontown, OH

Miles DearthSpherix Mineral ProductsLexington, SC

2017 INTERNATIONAL ELASTOMER CONFERENCE

DESIGN OF EXPERIMENT Processing & performance effects using solid microsphere process aids.

Elastomers Chosen …

The factors selected for this experiment are the types of treatment on spheres, part level of spheres

and elastomer type.

Factors Selected for EPDM …

Control without Spheres vs. Surface –Treated Aluminosilicate Spheres (D50=3 micron) vs. Non-Treated

Silica Nanospheres (150nm, compacted)

Factors Selected for Silicone …

With and without surface treated aluminosilicate spheres

Dependent variables that were measured:

� Rheology � Dispersion � Physical Properties � Mixing Cycle Time

Technical Requirements

�Non-Halogen FR Filler System

�Very Low VOC – Low Shrinkage

�High Tear Strength

�Dimensional Stability

�Reduced Scrap Rates

�Reduced Mixing Cycle-Time

�Greater Calendaring Efficiency

EPDM ROOFING

Material PHR

Vistalon 3702 60.00

Vistalon 9301 40.00

N550 85.00

Hard Clay 40.00

Hydral 710 30.00

Mistron Vapor 35.00

Sunpar 2280 80.00

ZnO 5.00

Stearic Acid 1.00

Carbowax 3350 1.00

Sulfur 1.00

BBTS 3.00

ZDBC 0.80

NSD or TASC 6.0

Total Parts (w/o and with) 381.8 387.8

EPDM ROOFING - FORMULATION

NSDNano Silica (neat) (150 nm)

TASCSulfur Reactive Aluminosilicate Ceramic (3 micron)

Microspheres Evaluated:

EPDM ROOFING – MIXING PROCEDURE

Upside Down Mixing Mixer Duration

Fillers and Spheres

(if present)

Ram Down

(Floating)0 - 40 Seconds

Small Powders Ram Down 40 - 100 Seconds

Oil Sweep 100 Seconds

EPDM Drop180, 160, or 140

Seconds

EPDM ROOFING - PROCESSING

Control (without spheres) NSD 6.0 phr TASC 6.0 phr

Mix at 180 Seconds Mix at 160 Seconds Mix at 160 Seconds

Mix at 140 Seconds Mix at 140 Seconds Mix at 140 Seconds

Absent Spheres NSD 6.0 phr TASC 6.0 phr

Observations Testing

Probe Temperature Durometer ASTM D2240-05

Mixing Yield (%) Tensile Strength ASTM D624-06a

Total Power (kWh/sec.) Oscillating Disc Rheometer ASTM D2084-11

Appearance Mooney Viscosity ASTM D1646-07 (2012)

EPDM ROOFING - PROCESSING

Control (A) Control (B) NSD (A) NSD (B) TASC (A) TASC (B)

Mix Time – Seconds 180 140 160 140 160 140

Yield Percentage 99.0% 96.7% 98.8% 99.1% 99.2% 99.9%

Probe Temperature °F 209 190 202 209 215 195

95.00% 96.00% 97.00% 98.00% 99.00% 100.00% 101.00%

TASC (A)

98.8%NSD (A)

96.7%Control (B)

99.0%Control (A)

99.9%TASC (B)

96.7%

99.9%NSD (B)

EPDM ROOFING – MDR RHEOLOGY 350°F/12’/42% STRAIN

Control (A) Control (B) NSD (A) NSD (B) TASC (A) TASC (B)

Tc90 5.68 6.13 5.52 6.81 6.56 6.15

ML 2.69 2.66 2.66 2.59 2.50 2.52

MH 25.19 24.56 23.62 23.40 25.59 25.24

ML (1+4) 212°F 54.46 52.93 54.71 53.55 52.08 52.48

EPDM ROOFING – PHYSICAL PROPERTIES

Control (A) Control (B) NSD (A) NSD (B) TASC (A) TASC (B)

Durometer 67 65 67 67 67 67

Tensile (psi) 1472 1460 1356 1393 1556 1493

Elongation (%) 617 626 624 613 640 611

300% Modulus 687 664 650 646 718 724

Tear Die C (lb/in) 193 188 190 183 203 202

EPDM - TENSILE STRENGTH

-7.88% NSD (A)

-4.59% NSD (B)

TASC (A) 5.71%

TASC (B) 2.26%

-10.00% -8.00% -6.00% -4.00% -2.00% 0.00% 2.00% 4.00% 6.00% 8.00%

Percent Difference From Control A

NSD (A) 1.13%

-2.08% NSD (B)

TASC (A) 3.73%

-3.00% -2.00% -1.00% 0.00% 1.00% 2.00% 3.00% 4.00% 5.00%

Percent Difference From Control A

EPDM - ELONGATION

-2.40% TASC (B)

-5.39% NSD (A)

-2.71% NSD (B)

TASC (A) 4.51%

-8.00% -6.00% -4.00% -2.00% 0.00% 2.00% 4.00% 6.00% 8.00% 10.00%

Percent Difference From Control A

EPDM – 300% MODULUS

TASC (B) 9.04%

-1.55% NSD (A)

-2.66% NSD (B)

TASC (A) 5.18%

-4.00% -2.00% 0.00% 2.00% 4.00% 6.00% 8.00%

Percent Difference From Control A

EPDM – TEAR DIE C

TASC (B) 7.45%

SILICONE EXTRUSION

�Better Dispersion

�Lower Standard Deviation

�Dimensional Stability

�Surface Finish

�Die Flow Rate

�Tear Properties

�Cycle Times

Material PHR

70 EXT Base 100.00

10 Micron Mineral Filler 36.00

Heat Stabilizer 1.00

DBPH – 50 1.00

Black Pigment 1.00

Peroxide-reactive microspheres (D50 = 3 micron) PR-TASC 5.00

SILICONE EXTRUSION - FORMULATION

SILICONE EXTRUSION - PROCESSING

About the ExperimentThis experiment was run on a 1.2 liter tilt body lab mixer

�Silicone base and additives were mixed for 30 seconds

�Mineral filler was added and the compound mixed to 30°C

�PR-TASC was added with the silicone base and other additives

SILICONE EXTRUSION - PROCESSING

Process Step Control (Mix Time) TASC (Mix Time)

Add polymer, additives and PR-TASC 30 Seconds 30 Seconds

Add mineral filler mix to 32°c 210 Seconds 160 Seconds

Mixer Discharge

Mineral filler on mixer walls

and agglomerated particles

on the surface of the batch

Small amount of PR-TASC

above the ram. No mineral

filler powder visible

Mill Rough edges Smooth

0 50 100 150 200 250

CONTROL

TASC

Total Cycle Time

The total cycle time of the PR-TASC batch was 21% faster than the control batch.

SILICONE EXTRUSION – TOTAL CYCLE TIME

190 SEC.

240 SEC.

Durometer 1.2%

Tensile -2.1%

Elongation 1.5%

Modulus -0.6%

Tear Die B 21.6%

-5.0% 0.0% 5.0% 10.0% 15.0% 20.0% 25.0%

Percent Difference From Control

SILICONE % DIFFERENCE FROM CONTROL

CONCLUSION – EPDM ROOFING

EPDM Roofing

� Microspheres show improvements in EPDM mixing efficiency.

� Not all microspheres behave the same way.

� Compatibilized, functional microspheres show promise in pushing the cycle time beyond

current limits without sacrificing physical properties.

� In some cases as is shown in this study, higher physical properties can be obtained while

pushing cycle time down.

In a model Silicone extrusion compound:

� A 3.5% loading of compatibilized, peroxide-reactive microspheres yielded a 21% reduction

mixing time.

� In addition, there were no unmixed filler agglomerates both at the mixer and in milling

compared to the control which exhibited some undispersed solids.

� A 3.5% loading of reactive microspheres exhibited no statistically significant change in

Durometer, Mooney viscosity and physical properties.

� The use of microspheres yielded a 21.6% increase in Die B tear.

CONCLUSION – SILICONE EXTRUSION

Thank You