Silicone rubber elastomer in the high consistency rubber or heat cure rubber (HCR) form can be formulated to use the addition cure Platinum catalyzed system rather than the peroxide cure. This presentation compares the two systems and outlines how the Pt addition cure system can be cost competitive.

1. AB Specialty Silicones
RAW MATERIAL SOLUTIONS
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2. A B S P E C I A L T Y S I L I C O N E S | W A U K E G A N , I L | W W W . A N D I S I L . C O M
Outline
• History of platinum cure
• Addition cure applications
• Basic silicone cure chemistry
• HCR peroxide versus HCR platinum cost
calculator
• Practical considerations
• Mechanical property considerations
• Process considerations
• Commercial considerations
• Conclusion

3. A B S P E C I A L T Y S I L I C O N E S | W A U K E G A N , I L | W W W . A N D I S I L . C O M
The Platinum …Standard
 ChloroPlatinic Acid developed by J.L. Speier for batch reactions to create new
organic / Silicone hybrid chemistry.
• Not well suited for curing rubber
 The platinum catalyzed reaction of a silicone hydride with the silicone vinyl
group to create rubber goes back to the original work in the 1960s of Bruce
Ashby who became famous for the Ashby platinum catalyst. Patent US3159601
 This work was extended by Bruce Karstadt in 1970 when he patented the
platinum vinyl siloxane complex that we still use today. Patent US 3715334 and
US 3775452
 The benefits of utilizing this addition cure between the vinyl and silicon
hydride's include a very rapid cure speed and the absence of decomposition
byproducts typical when curing using traditional peroxide.

4. A B S P E C I A L T Y S I L I C O N E S | W A U K E G A N , I L | W W W . A N D I S I L . C O M
Platinum Catalysts for Silicone Crosslinking
Karstedt catalyst
Ligand: Andisil 2827
Ashby catalyst
Ligand: Andisil MVC

5. A B S P E C I A L T Y S I L I C O N E S | W A U K E G A N , I L | W W W . A N D I S I L . C O M
Addition Cure Application history
• In the first applications the high cost but very low level of by-products make Addition
cure a natural for medical applications
 Pharmaceutical Tubing by extrusion is the first major market
 Implants for joint and reconstructive surgery
• Food contact applications became popular
 Cake molds
 Spatulas and utensils
• Other applications developed as LSR formulations became more specialized
 HVI for electrical infrastructure
 Over-molding low temperature plastic
• Most Addition cure applications are still based on LSR technology
 2 component liquid systems
 Limited ability to customize the formulation
• Specialized expensive injection machines
• Expensive custom tooling
• HCR Addition cure is now readily available from ABSS

6. A B S P E C I A L T Y S I L I C O N E S | W A U K E G A N , I L | W W W . A N D I S I L . C O M
Addition cure HCR
• Emerging molded goods applications;
 Spark Plug Boots
 Connector seals
• Balance between Vinyl and SiH level is important
 More chemical information needed, less empirical vs Peroxide
 Limited information available for VMQ Base vinyl levels
 VMQ Gum not readily available and requires addition of Fumed silica
• Few commercial offerings
 Addisil line from Momentive
• Limited shelf life in 1K compound
• Customization difficult
 2K compounds
• Available from some custom compounders
• Simple 2 roll addition of Platinum / Inhibitor Masterbatch
• In-House mixing of Base and other raws is most cost effective
 Use short shelf life to advantage
 Use formulation expertise of Raw Material supplier such as ABSS
 Custom compound to meet customer Price and Property targets

7. A B S P E C I A L T Y S I L I C O N E S | W A U K E G A N , I L | W W W . A N D I S I L . C O M
Si
O
Si
O
Si
D
Si
O
Si
O
Si
O
Si
H
N M
Pt
Si
O
Si
O
Si
O
Si
N M
Si
O
Si
O
Si
+
ADDITION CURE
Vinyl Terminated Polydimethylsiloxanes

8. A B S P E C I A L T Y S I L I C O N E S | W A U K E G A N , I L | W W W . A N D I S I L . C O M
Si
O
Si
O
Si
D
Pt
+
H
Si
O
Si
O
Si
H
D
Si
O
Si
O
Si
D
Si
O
Si
O
Si
H
D
ADDITION CURE
Addition Cure-Chain Extension Reaction

9. A B S P E C I A L T Y S I L I C O N E S | W A U K E G A N , I L | W W W . A N D I S I L . C O M
VMQ Peroxide cure
• Cross-link occurs through random
abstraction of a methyl Hydrogen
• Residual Peroxide ROH and R’OH
Andigum H110-0
Andigum H101-1
Peroxide activation
Radical on Polymer
Cross-link through methyl group

10. A B S P E C I A L T Y S I L I C O N E S | W A U K E G A N , I L | W W W . A N D I S I L . C O M
VMQ Platinum Addition cure
C1142A; Pt
Andisil MQH
Andisil CE
Andisil XL
Andigum H110-0

11. A B S P E C I A L T Y S I L I C O N E S | W A U K E G A N , I L | W W W . A N D I S I L . C O M
Addition cure compound
Description INGREDIENT Note PPHR density volume $/lb Cost
VMQ Gum
Andigum
H110-0
0.04%
Vinyl 97 0.97 100.00 $1.75 169.75
VMQ Gum
Andigum
H101-8 8% Vinyl 3 0.97 3.09 $6.00 18.00
Fumed Silica Andifil AS 200
200m2/g
m 25 2.2 11.36 $2.75 68.75
Process Aid Andisil OH 40 5 0.98 5.10 $3.40 17.00
Filler Min-u-sil 5 20 2.65 7.55 $0.65 13.00
Inhibitor Andisil MVC 0.1 0.997 0.10 $60.00 6.00
CrossLinker Andisil XL 10 4 0.98 4.08 $4.75 19.00
Platinum
Catalyst C1142A 5ppm 0.0375 $ 800.00 $30.00
s. g.1.17
Formula cost per pound 2.24
$/lb
compound

12. A B S P E C I A L T Y S I L I C O N E S | W A U K E G A N , I L | W W W . A N D I S I L . C O M
Comparison Peroxide compound cost
Description INGREDIENT Note PPHR density volume $/lb Cost
VMQ Gum
Andigum
H110-0
0.04%
Vinyl 97 0.97 100.00 $1.75 169.75
VMQ Gum
Andigum
H101-8 8% Vinyl 3 0.97 3.09 $6.00 18.00
Fumed Silica Andifil AS 200 200m2/gm 25 2.2 11.36 $2.75 68.75
Process Aid Andisil OH 40 5 0.98 5.10 $3.40 17.00
Extending
filler Min-u-sil 5 20 2.65 7.55 $0.65 13.00
Coagent TIAC 0.1 1.16 0.09 $15.00 1.50
Peroxide DBPH 0.7 0.877 0.71 $6.00 4.20
Specific Gravity 1.17
Formula cost per pound $1.94
$/lb
compound

13. A B S P E C I A L T Y S I L I C O N E S | W A U K E G A N , I L | W W W . A N D I S I L . C O M
Economics of molding
• One component addition cure commercial product for
molding
 $4.50 per pound
• Car companies want annual 5% reduction in cost every
year for 5 years
• Assume existing Tooling and Presses
 Same # of operators
 Same Max temp during cure
# Cavities Cure time, Minutes Parts per 8 hr shift
Platinum 128 1 61,440
Peroxide 128 5 12,288

14. A B S P E C I A L T Y S I L I C O N E S | W A U K E G A N , I L | W W W . A N D I S I L . C O M
Part Weight,
lbs
Material/
Part cost
Conversion
cost, $/hr
0.064 $ 75.00
Platinum 0.1435 $ 0.00977 $ 0.15
Peroxide 0.1240 $ 0.04883 $ 0.17
Bottom line part cost
• Cost in use is lower
• Shorter Cycle time in existing tooling offsets higher material cost
• Faster cure offers opportunity for lower cost with further process
optimization
• Conversion cost is Labor, Overhead, Fixed cost, SG&A
Cost per Part

15. A B S P E C I A L T Y S I L I C O N E S | W A U K E G A N , I L | W W W . A N D I S I L . C O M
Adjustments to further reduce cost
Sample Curative Duro Tensile, psi Elongation % Tear, ppi
HS-3431 DBPH, 0.7% 28 903 480 62
XL 10 / Pt 1095 634 111
HS-3471 DBPH, 0.7% 66 1272 287 102
XL 10 / Pt 72 1080 299 130
• Better properties allow increase in extending fillers and further cut costs
• Lower temperature cure is possible, as low as 120C
• More basic formulating tools are available to optimize properties
 Standard Andisil XL Cross-linkers, from 0.95 to 7 mm/gm
• Custom products with Phenyl are available
 Wide range of Vinyl Gum, from 0.04% up to 8% vinyl
 Other Vinyl sources such as Vinyl resin and organic additives (TIAC)

16. A B S P E C I A L T Y S I L I C O N E S | W A U K E G A N , I L | W W W . A N D I S I L . C O M
Pros and Cons of Addition cure
• Limitations of Addition cure
 May need investment in mixing equipment
 1K compound has a limited shelf life
 2K compound requires mixing prior to use
 Cure inhibition contaminants can cause problems
• Facility controls usually needed to avoid cross contamination
• Benefits of addition cure
 Cost savings for specific parts
 Can use existing tooling and equipment
• Smaller tooling / fewer cavitations to reach same production rate
 Greater formulating flexibility; Phenyl, Fluoro substitution possible
 No post cure needed
 Can be food contact or Medical Grade; CFR 21 Part 177.2600; ISO 10993-5

17. A B S P E C I A L T Y S I L I C O N E S | W A U K E G A N , I L | W W W . A N D I S I L . C O M
Conclusions
 Step change in curing speed
 Thoughtful implementation can create significant cost
savings
 Provides clear differentiation from competitors
 Increased utilization of exiting equipment and tooling
 Versatile chemistry for custom compounds
 Less risk of competing with the Majors
 Raw material suppliers like ABSS with expertise can
provide technical support
 ABSS has All the basic raw materials available in one stop

18. A B S P E C I A L T Y S I L I C O N E S | W A U K E G A N , I L | W W W . A N D I S I L . C O M
ABSS Rubber Product line