The recommended starting point for platinum catalysts is 20 ppm platinum or 0.05-0.1 parts of complex per 100 parts of vinyl-addition silicone formulation. Rhodium catalyst starting point is 30 ppm based on rhodium. Other platinum concentrations are available upon request.
Relative activity at room temperature:
SIP6829.2 < INRH078 < SIP6833.2 < SIP6832.2 < SIP6830.3 < SIP6831.2LC < SIP6831.2
Precious Metal Catalysts for Vinyl-Addition Silicone Cure
| Product code | Name | Platinum % in solvent | Density | CAS | Comments |
|---|---|---|---|---|---|
| SIP6829.2 | Platinum carbonyl cyclovinylmethylsiloxane complex | 2.1% in vinylmethylcyclicsiloxanes | 1.02 | [73018-55-0] TSCA | catalyst for Si-H addition to olefins - silicone vinyl-addition cure catalyst employed in elevated temperature curing silicones |
| SIP6830.3 | Platinum-divinyltetramethyldisiloxane complex | 3-3.5% in vinyl-terminated PDMS, neutral | 0.98 | [68478-92-2] TSCA | catalyst for Si-H addition to olefins - silicone vinyl-addition cure catalyst employed in room temperature curing silicones |
| SIP6831.2 | Platinum-divinyltetramethyldisiloxane complex | 2.1-2.4% in xylene | 0.90 | [68478-92-2] TSCA | “hot” catalyst employed in room temperature curing silicones flashpoint: 38 °C |
| SIP6831.2LC | Platinum-divinyltetramethyldisiloxane complex | 2.1-2.4% in xylene | 0.90 | [68478-92-2] TSCA | low color flashpoint: 38 °C |
| SIP6832.2 | Platinum-cyclovinylmethylsiloxane complex | 2-2.5% in cyclic methylvinylsiloxanes, neutral | 1.02 | [68585-32-0] TSCA | catalyst for Si-H addition to olefins - silicone vinyl-addition cure catalyst employed in moderate elevated temperature curing silicones |
| SIP6833.2 | Platinum-octanaldehyde/octanol complex | 2.0-2.5% in octanol | 0.84 | [68412-56-6] TSCA | catalyst for Si-H addition to olefins - silicone vinyl-addition cure catalyst increases flammability resistance of silicones |
| INRH078 | Tris(dibutylsulfide)rhodium trichloride | 3.0-3.5% rhodium in toluene | 0.91 | [55425-73-5] TSCA | catalyst for Si-H addition to olefins - silicone vinyl-addition cure catalyst, less susceptible to inhibition employed in moderately elevated temperature curing silicones |
Poisons for platinum catalysts used in vinyl-addition crosslinking must be avoided. Examples are:
- Sulfur compounds (mercaptans, sulfates, sulfides, sulfites, thiols, and rubbers vulcanized with sulfur will inhibit contacting surfaces)
- Nitrogen compounds (amides, amines, imides, nitriles)
- Tin compounds (condensation-cure silicones, stabilized PVC)
The following are the most common materials employed to modify aspects of platinum-cured vinyl-addition silicones.
Inhibitors and Moderators of Hydrosilylation
| Product code | Name | Molecular Weight | Boiling Point (°C/mmHg) | Density | Refractive Index | Flashpoint (°C) | CAS |
|---|---|---|---|---|---|---|---|
| SID4613.0 | 1,3-divinyltetramethyldisiloxane | 186.40 | 139 | 0.811 | 1.4123 | 24 | [2627-95-4] TSCA |
| SIT7900.0 | 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane | 344.66 | 110/10 | 0.998 | 1.4324 | 112 | [2554-06-5] TSCA |
Adhesion Promoters
| Product code | Name | Molecular Weight | Boiling Point (°C/mmHg) | Density | Refractive Index | Flashpoint (°C) | CAS |
|---|---|---|---|---|---|---|---|
| SIA0540.0 | Allyltrimethoxysilane | 162.26 | 146-148 | 0.963 | 1.4036 | 46 | [2551-83-9] TSCA |
Special Crosslinkers
| Product code | Name | Molecular Weight | Boiling Point (°C/mmHg) | Density | Refractive Index | Flashpoint (°C) | CAS | Comments |
|---|---|---|---|---|---|---|---|---|
| SIP6826.0 | phenyltris(dimethylsiloxy)silane | 330.68 | 91/2 | 0.942 | 1.440 | 87 | [18027-45-7] TSCA | crosslinker for medium refractive index vinyl-addition silicone elastomers |
| SIT7278.0 | tetrakis(dimethylsiloxy)silane | 328.73 | 188-190 | 0.886 | 1.3841 | 67 | [17802-47-2] TSCA | crosslinker for Pt cure 2-component RTVs |
| SIT8372.4 | trifluoropropyltris(dimethylsiloxy)silane | 350.63 | 98-99/40 | 0.962 | 1.3753 | -- | [3410-32-0] TSCA |
Acetoxy Crosslinkers for Condensation Cure Silicones
| Product code | Name | Molecular Weight | Density | Melting Point (°C) | Flashpoint (°C) | CAS | Comments |
|---|---|---|---|---|---|---|---|
| SID2790.0 | Di-t-butoxydiacetoxysilane, tech-96 | 292.40 | 1.0196 | -4 | 95 | [13170-23-5] TSCA | adhesion promoter for silicone RTVs |
| SIE4899.0 | Ethyltriacetoxysilane | 243.28 | 1.143 | 7-9 | 106 | [17689-77-9] TSCA | liquid crosslinker for silicone RTVs |
| SIM6519.0 | Methyltriacetoxysilane, 95% | 220.25 | 1.175 | 40 | 85 | [4253-34-3] TSCA | most common crosslinker for condensation cure silicone RTVs vapor pressure, 94 °C: 9 mm |
| SIM6519.2 | Methyltriacetoxysilaneethyltriacetoxysilane 80:20 blend | -- | -- | -- | -- | [4253-34-3] | liquid crosslinker blend for silicone RTVs |
| SIV9098.0 | Vinyltriacetoxysilane | 232.26 | 1.167 | -- | 88 | [4130-08-9] TSCA | -- |
Alkoxy Crosslinkers for Condensation Cure Silicones
| Product code | Name | Molecular Weight | Density | Melting Point (°C) | Flashpoint (°C) | CAS | Comments |
|---|---|---|---|---|---|---|---|
| SIB1817.0 | Bis(triethoxysilyl)ethane (hexaethoxydisilethylene) | 354.59 | 0.957 | [16068-37-4] TSCA | additive to formulations that enhances adhesion | ||
| SIM6555.0 | Methyltriethoxysilane | 178.30 | 0.8948 | [2031-67-6] TSCA | |||
| SIM6560.0 | Methyltrimethoxysilane | 136.22 | 0.955 | -78 | 8 | [1185-55-3] TSCA | viscosity: 0.50 cSt |
| SIT7110.0 | Tetraethoxysilane (tetraethylorthosilicate, TEOS) | 208.33 | 0.9335 | -77 | 46 | [78-10-4] TSCA | vapor pressure: 20 °C/11.8 mm viscosity: 0.8 cSt |
| SIT7777.0 | Tetra-n-propoxysilane | 264.44 | 0.9158 | < -80 | 95 | [682-01-9] TSCA | viscosity: 1.66 cSt |
| SIV9220.0 | Vinyltrimethoxysilane | 148.23 | 0.970 | 28 | [2768-02-7] TSCA | melting point: 148.23 °C viscosity: 0.6 cSt |
Oxime Crosslinkers for Condensation Cure Silicones
| Product code | Name | Molecular Weight | Density | Melting Point (°C) | Flashpoint (°C) | CAS | Comments |
|---|---|---|---|---|---|---|---|
| SIM6590.0 | Methyltris(methylethylketoximino) silane, tech-95 | 301.46 | 0.982 | -- | 90 | [22984-54-9] TSCA | neutral crosslinker for condensation cure silicones |
| SIV9280.0 | Vinyltris(methylethylketoximino) silane, tech-95 | 313.47 | 0.982 | -- | -- | [2224-33-1] TSCA | -- |
Enoxy (Acetone) Crosslinkers for Condensation Cure Silicones
| Product code | Name | Molecular Weight | Density | Melting Point (°C) | Flashpoint (°C) | CAS | Comments |
|---|---|---|---|---|---|---|---|
| SIV9209.0 | Vinyltriisopropenoxysilane, tech-95 | 226.35 | 0.926 | -- | -- | [15332-99-7] TSCA | -- |
| Product code | Name | Molecular Weight | Density | CAS | Comments | Use Level % |
|---|---|---|---|---|---|---|
| SNB1100 | Bis(2-ethylhexanoate)tin tech-95 (tin II octoate) | 405.11 | 1.28 | [301-10-0] TSCA | contains free 2-ethylhexanoic acid catalyst for two-component condensation RTVs highest activity, short pot life, does not cause silicone reversion | 0.1-0.3 |
| SNB1101 | Bis(2-ethylhexanoate)tin, 50% in PDMS (tin II octoate) | 405.11 | 1.12 | [301-10-0] TSCA | predilution results in better compatibility with silicones | -- |
| SNB1710 | Bis(neodecanoate)tin tech-90 (tin II neodecanoate) | 461.23 | 1.16 | [49556-16-3] TSCA | contains free neodecanoic acid dark viscous fluid catalyst for two-component condensation RTVs slower than SNB1100 does not cause reversion | 0.2-0.4 |
| SND2930 | Di-n-butylbis(2-ethylhexylmaleate)tin, tech-95 (dibutyltin diisooctylmaleate) | 687.46 | 1.145 | [25168-21-2] TSCA | catalyst for one-component RTVs good adhesion to metal substrates | -- |
| SND2950 | Di-n-butylbis(2,4-pentanedionate)tin, tech-95 | 431.13 | 1.2 | [22673-19-4] TSCA | flashpoint: 91 °C stable tin+4 catalyst with reduced reversion can be used in conjunction with SND3260 catalyst in silicone RTV cures.1,2 | -- |
| SND3110 | Di-n-butylbutoxychlorotin, tech-95 | 341.48 | -- | [14254-22-9] TSCA | catalyst for two-component condensation cure silicone RTVs3 | -- |
| SND3160 | Di-n-butyldiacetoxytin, tech-95 (dibutyltindiacetate) | 351.01 | 1.320 | [1067-33-0] TSCA | melting point: -10 °C; flashpoint: 231 °C high activity catalyst for one-component condensation RTVs suitable for acetoxy cure and neutral alkoxy cure | 0.1-0.3 |
| SND3260 | Di-n-butyldilauryltin, tech-95 (dibutyltin dilaurate) | 631.55 | 1.066 | [77-58-7] TSCA | flashpoint: 231 °C; viscosity: 31-34 cSt widely used catalyst for two-component condensation RTVs moderate activity, longer pot life, employed in silicone emulsions FDA allowance as curing catalyst for silicones- 21CFR121.2514 | 0.2-0.6 |
| SND4220 | Dimethyldineodecanoatetin, tech-95 (dimethyltin dineodecanoate) | 491.26 | 1.136 | [68928-76-7] TSCA | flashpoint: 153 °C catalyst for one- and two-component condensation RTVs | 0.5-0.8 |
| SND4240 | Dimethylhydroxy(oleate)tin, 85% | 447.23 | 1.15 | [43136-18-1] TSCA | viscous liquid elevated temperature catalyst for condensation cure silicones | 0.8-1.2 |
| SND4430 | Dioctyldilauryltin tech-95 (dioctyltindilaurate) | 743.76 | 0.998 | [3648-18-8] TSCA | flashpoint: 70 °C low toxicity, moderate activity, longer pot life applications in silicone emulsions and solvent-based adhesives | 0.8-1.3 |
| SNT7955 | Tin II oleate, tech-90 | 681.61 | 1.06 | [1912-84-1] | contains free oleic acid | -- |
Titanate Catalysts for Alkoxy and Oxime Neutral-Cure RTVs
| Product code | Name | Molecular Weight | Viscosity (cSt) | Flashpoint (°C) | Density | Refractive Index | CAS | Comments |
|---|---|---|---|---|---|---|---|---|
| AKT853 | Titanium di-n-butoxide (bis-2,4-pentanedionate) | 392.32 | > 110 | 1.085 | -- | [16902-59-3] TSCA | ||
| AKT855 | Titanium diisopropoxide(bis-2,4-pentanedionate), 75% in isopropanol | 364.26 | 8-11 | 12 | 0.992 | 1.4935 | [17927-72-9] TSCA | miscible: aqueous acetone, most organics |
| AKT865 | Titanium diisopropoxide bis(ethylacetoacetate), 95% | 424.33 | 45-55 | 27 | 1.05 | -- | [27858-32-8] TSCA | 11.0 - 11.2% Ti |
| AKT867 | Titanium 2-ethylhexoxide (tetraoctyltitanate) | 564.79 | 120-130 | 71 | 0.937 | 1.482 | [1070-10-6] TSCA | 8.4-8.6% Ti boiling point/mm: 194 °C/0.25 catalyst for silicone condensation RTVs |
| SIT7305.0 | Titanium trimethylsiloxide (tetrakis(trimethylsiloxy)titanium) | 404.66 | -- | 51 | 0.900 | 1.4278 | [15990-66-6] | boiling point/mm: 110 °C/10 |
Peroxide Catalysts for Heat-Cured Silicone Rubber
| Product code | Name | Molecular Weight | Density | Silicone Compounding Temp (°C) | Cure Temp (°C) | CAS | Comments |
|---|---|---|---|---|---|---|---|
| SID3352.0 | 2,4-dichlorobenzoyl peroxide, 50% in PDMS | 380.00 | 1.26 | < 50 | > 90 (rec: 105-120) | [133-14-2] TSCA | paste consistency |
| SID3379.0 | Dicumyl peroxide, 25% in PDMS | 270.36 | -- | < 60 | > 125 (rec: 155-175) | [80-43-3] TSCA | 25% dicumyl peroxide, 40% PDMS, 35% calcium carbonate |
Pigment concentrates in silicone oil are readily dispersed in all silicone cure systems. Pigments are generally mixed at 1-4 parts per hundred with the A part of two part vinyl-addition silicones. Silicone coatings generally employ 2-6 parts per hundred.
Pigment Concentrates (dispersed in silicone)
| Product Code | Color | Concentration % | Pigment Type |
|---|---|---|---|
| PGWHT01 | White | 45 | titanium dioxde |
| PGRED01 | Red | 50 | cadmium sulfoselenide |
| PGORR01 | Orange-red | 45 | iron oxide |
| PGORA01 | Orange | 15-25 | diarylide pyrazolone |
| PGYLW01 | Yellow | 55 | bismuth vanadate |
| PGGRN01 | Green | 30-40 | cobalt titanate |
| PGBLU01 | Blue | 45 | sodium aluminosulfosilicate |
| PGFLS01 | Beige | 50-60 | mixed Fe-Mg-Ti oxides |
| PGBRN01 | Brown | 55 | mixed Fe-Cr-Cu oxides |
| PGBLK01 | Black - non-conductive | 55 | manganese ferrite |
| PGBLK02 | Black - conductive | 45 | carbon |
| PGXRA01 | X-ray opaque | 35 | barium sulfate |
Dyes in silicone oils provide coloration without compromising transparency. The fluids may be used directly in applications such as gauges or as tints for silicone elastomers.
DMS-T21BLU Blue dye in 100 cSt silicone
DMS-T21RED Red dye in 100 cSt silicone
Hexamethyldisilazane-treated (HMDZ-treated) silica is the preferred filler for silicones. The material is very fine and hydrophobic. Enclosed high-shear compounding equipment is required for adequate dispersion.
Fillers and Reinforcements
| Product code | Name | Molecular Weight | Density | CAS | Comments |
|---|---|---|---|---|---|
| SIC2050.0 | Calcium metasilicate (Wollastonite) | 116.16 | 2.69 | [13983-17-0] TSCA | hardness: 4.5-5 weakly reinforcing filler for silicone rubbers- suitable for putty |
| SIS6962.0 | Silicon dioxide amorphous, hexamethyldisilazane-treated (fumed silica, HMDZ-treated) | 60.09 | 2.2 | [168909-20-6]/[7631-86-9] TSCA | surface area, 150-200 m2/g SiO2 ultimate article size: 0.02 m reinforcing filler for high tear strength silicone rubbers |
| SIS6964.0 | silicon dioxide, crystalline (quartz powder) | 60.06 | 2.65 | [7631-86-9] TSCA | SiO2 hardness: 7.0 |
| Product code | Structure | Name | Density | Melting Point (°C) | CAS | Comments |
|---|---|---|---|---|---|---|
| SIT7520.0 |  | Tetramethylammonium siloxanolate | 0.98 | -- | [68440-88-0] TSCA | 1.5-2.0% nitrogen as endcapped PDMS catalyst for ring opening polymerization of cyclic siloxanes at 85-100 °C decomposes > 120 °C with release of trimethylamine |
| INPH055 |  | Polyphosphonitrilic chloride, 95% | -- | 60-80 | [31550-05-7] | for silanol oligomer polymerization1,2,3 |
| OMBO037 |  | (p-isopropylphenyl)(p-methylphenyl)iodonium tetrakis(pentafluorophenyl) borate | -- | 120-133 | [178233-72-2] TSCA | UV initiator for cationic polymerizations, e.g. cycloaliphatic epoxides |