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Evaluation and Characterization of Silane Coupling Agents in Silica Filled
Evaluation and Characterization of Silane Coupling Agents in Silica Filled, Zisnet® Cured, Hydrin® Copolymer Compounds
Overview
• Introduction – Objective – Purpose • Chemistry of ECO & Silanes -- Reviewed • Evaluation Recipes • Original Physical Properties • Aged Properties • Conclusions
Introduction
• Standard compounding technique to use silane coupling agents to enhance properties of mineral filled stocks • Usual data shows Sulfur or Peroxide cure systems • Little if any data on Cl substitution type cures – Zisnet® (TCY) • The purpose of this study is to evaluate a number of commonly available silanes in Hydrin® copolymer; – Zisnet® cure – Mineral filled – Various aging scenarios
Review of Hydrin : Polymer Structure vs Property
CO (homopolymer) ECO (copolymer) GECO (terpolymer)
H2 C C H
O
H2 C
O C H2
H2 C
O C H CH 2 O CH 2 HC
m
CH 2
n
o
Cl
Epichlorohydrin •Polarity •Heat + Chemical •Gas Permeation Resistance
Ethylene oxide •Low Temperature Flex •Electrical – Dissipation •Rebound
Allyl glycidal ether •Unsaturation •Sulfur or Peroxide Cure •Sacrificial Site •O3 Attack •Anti-thermal Antidegradation •Low Temperature Flex
CH 2
Generalized Formulation
Typical Formulation for Polyepichlorohydrin Elastomer: Ingredients Polymer Filler Plasticizer (Ether/Ester) Antioxidant Process Aid Acid Acceptor Curatives phr 100 70 10 1 1 5 1 range, phr 0-130 0-30 0-2 0-3 3-10 0.3-2.0
A critical component!
Non-Lead Cure System
Ingredient (phr) Magnesium Oxide Calcium Carbonate Zisnet® F-PT DPG P.V.I.
Function acid acceptor acid acceptor curative accelerator retarder
Initial 3 5 0.5-1.0
Faster 3 5 0.8 0.2-1.0
Slower 1 5 0.8 0.2-1.0
Readily adjustable to fit your process.
Mechanism -- Lead Free Curing of Hydrin
2, 4, 6-Trimercapto1, 3, 5-triazine Trithiocyanuric acid Zisnet F-PT
SH
SH
N
N
N MgO Heat
N + Mg++ OH
HS
N
S-H SH
HS
N Mercaptide
S-
Polymer chain
N N
CH2-S
S-CH2
+ H20 + MgCl2
Polymer chain
N
Chemistry of Silica, Silane & Polymer
• Unique purpose of coupling agents – Good modifiers because •React with silanol groups on filler surface •Gives a strong bond •Contains a functional group that reacts with the polymer during vulcanization – Added benefits •To ‘wet out’ fillers for better dispersion •To reduce interference of silica with cure system
POLYMER CHAIN
CH2 H2Si O OH Si OH Si Si
CH2
CH2
R
OH OH Si OH Si Si
COUPLING AGENT
SILICA FILLER
Coupling Agents Studied
Trade Name Si-230 Si-263 Si-69 A-189 SCA 98WT Deolink TESPT Z-6940
Chemical Name Chloropropyltriethoxysilane Mercaptosilane Bis (triethoxysilylpropyl) polysulfide Gamma-mercaptopropyltrimethoxysilane Bis (3-triethoxysilylpropyl) tetrasulfide + CaSiO3 Bis (3-triethoxysilylpropyl) polysulfane + TPE Bis (3-triethoxysilylpropyl) + sulfides + silanes
Supplier Degussa Degussa Degussa GE A
dvanced Materials Struktol RT Vanderbilt RT Vanderbilt
Evaluation Recipes
CONTROL HYDRIN® C2000LL HYDRIN® HISIL 532EP PLASTHALL 226 CARBOWAX 3350 STEARIC ACID NAUGARD 445 VANOX MTI CALCIUM CARBONATE MAGNESIUM OXIDE ZISNET® F-PT ZISNET® DPG RETARDER SAFE Si230 Si263 Si69 A189 98WT TESPT Z6940 100 40 10 2 1 1 0.5 5 1 0.8 0.5 0.3 2 2 2 2 2 3.5 2 Si230 Si263 Si69 A189 98WT TESPT Z6940
Rheology
Control Mooney Viscosity ML(1+4) @ 100C 59
Si230 67
Si263 65
Si69 62
A189 59
98WT 67
TESPT 61
Z6940 64
Mooney Scorch ML (1+30) @ 125C Minimum Viscosity T5 (mins) (mins) T35 (mins) (mins) 53 3.8 6.2 60 3.6 5.5 60 2.7 4.2 54 4.6 6.7 51 3.4 5.4 59 4.5 6.6 53 4.6 7.1 54 4.4 6.8
ODR 45’ / 180C / 100 cpm / 3 deg 45’ arc ML (lbf/in) (lbf/in) MH (lbf/in) (lbf/in) Ts2 (mins) (mins) Tc90 (mins) (mins) 11.7 66.6 0.9 6.6 12.9 70.4 1.0 9.4 12.7 75.2 0.9 8.7 12.5 74.7 1.3 17.4 13.0 77.4 1.2 9.4 13.3 75.3 1.1 15.1 12.6 69.0 1.2 11.3 13.1 72.5 1.3 18.4
Original Physical Properties
Control Hardness A, pts M100, psi Tensile, psi Elongation, % 52 188 1460 811
Si230 59 284 1536 648
Si263 58 301 1290 575
Si69 58 275 1212 572
A189 60 343 1453 450
98WT 60 275 1181 588
TESPT 58 247 1262 683
Z6940 60 294 1311 593
Die C Tear, ppi
158
236
205
199
227
202
191
218
Compression Set (Button) 22h / 100C, % 22h / 125C, % 20 33 12 22 10 20 25 37 7 15 24 37 25 39 23 36
DIN Abrasion, Loss, grams
432
301
304
313
230
330
339
335
Compression Set
Compression Set
22 hours on ASTM Button
40
Percent Set
30 20 10 0
Si 26 3 Si 23 0 Si 69 18 9 on tr ol C TE SP Z6 94 0 98 W T A T
100C
125C
Abrasion Resistance (DIN)
Abrasion Resistance
(DIN Method)
500
Wt loss, grams
400 300 200 100 0
Si 23 0 Si 26 3 Si 69 18 9 on tr ol C TE SP Z6 94 0 T 98 W A T
Hot Air Aging
Air Oven 70h / 125C
40
Property Change
20 0 -20 -40
Si 23 0 Si 26 3 Si 69 18 9 on tr ol C TE SP Z6 94 0 98 W T A T
Hardness A, pts
Tensile, %
Elongation, %
Hotter Air Aging
Air Oven 70h / 150C
60 40 20 0 -20 -40 -60
Si 26 3 Si 23 0 Si 69 18 9 C TE SP Z6 94 0 on tr ol 98 W T A T
Property Change
Hardness A, pts
Tensile, %
Elongation, %
Hot Oil Aging
IRM903 Oil 70h / 125C
40 30 20 10 0 -10 -20 -30 -40
Si 23 0 Si 26 3 Si 69 18 9 on tr ol C TE SP Z6 94 0 98 W T A T
Property Change
Hardness A, pts
Tensile, %
Elongation, %
Volume, %
Hotter Oil Aging
IRM903 Oil 70h / 150C
60 40 20 0 -20 -40 -60
Si 23 0 Si 26 3 Si 69 18 9 on tr ol C TE SP Z6 94 0 98 W T A T
Property Change
Hardness A, pts
Tensile, %
Elongation, %
Volume, %
Hot Water Aging
Distilled Water 70h / 100C
60 40 20 0 -20 -40 -60
Si 23 0 Si 26 3 Si 69 18 9 on tr ol C TE SP Z6 94 0 98 W T A T
Property Change
Hardness A, pts
Tensile, %
Elongation, %
Volume, %
Compounders Note: Hydrin® differs from conventional elastomers in that the use of silica filler will REDUCE water swell, compared to that of carbon black fillers.
Conclusions
The use of coupling agents in Hydrin® mineral filled copolymers using t
he Zisnet® cure system are; – Viable to get improved physical properties – Silane A-189 is the best overall choice as it performed best over the entire range of tests – In hot water aging it is best NOT to use coupling agents – The control (no silane) was best • If one is needed use – SCA 98WT or TESPT
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