AB Specialty Silicones / ANDISIL Silanes, Silicone Polymers and Catalysts

Selection and quotation of Andisil® silicone raw materials: silanol and vinyl polymers, oxime and SiH crosslinkers, silanes, platinum and tin catalysts, fumed silica and SF fluids.

OH and MOH Silanol Polymers for RTV

Andisil® OH reactive silicone polymers are silanol functional fluids with various viscosities and silanol contents for one part RTV sealants and filler treatment. Low viscosity grades act as reactive diluents. The OH range runs from 40 cSt to 300,000 cP, MOH grades start at 100 cSt.

OH 40: 3.5% silanol, 40 cSt
OH 70: 1.25% silanol, 70 cSt
OH 50,000: 50,000 cP
MOH 1,000: monofunctional, 1,000 cSt

MOS, VOS and POS Oxime Crosslinkers

Andisil® oxime crosslinkers are liquid raw materials for neutral condensation curing silicone sealants. The range covers methyl, vinyl and phenyl tris(MEKO)silane, tetrakis(MEKO)silane in toluene and the MT 9010 and VT 6535 blends. Hexamethyldisilazane HMDZ is offered for one part systems.

MOS: methyl tris(MEKO)silane
VOS: vinyl tris(MEKO)silane
MT 9010: 90% MOS / 10% TOS
HMDZ: hexamethyldisilazane

Silanes as Adhesion Promoters and Crosslinkers

Andisil® silanes are used as adhesion promoters, coupling agents, crosslinkers, moisture scavengers, resin additives and surface modifiers. The range covers acetoxy, alkoxy, amino, epoxy, methacryloxy, sulfur, ureido and vinyl silanes.

1100: aminopropyltriethoxysilane
187: glycidoxypropyltrimethoxysilane
174: methacryloxypropyltrimethoxysilane
MTAS: methyltriacetoxysilane

VS Vinyl Polymers and VQM Vinyl Resins

Andisil® VS polymers are vinyl-terminated dimethylpolysiloxanes used as base or blend polymers to create the desired hardness. Viscosity runs from 6 cSt to 165,000 cP and vinyl content from 3.00 to 0.015 mmoles/gm. VQM vinyl resins raise mechanical properties of addition cured elastomers.

VS 1,000: 0.11 mmoles/gm vinyl
VS 165,000: 165,000 cP
VQM 1: refractive index 1.406
VDM 500: 0.28 mmoles/gm vinyl

XL SiH Crosslinkers and CE Chain Extenders

Pendant XL crosslinkers have random pendant silicon-hydride functionality and are trimethylsiloxy-terminated, hybrid grades carry pendant and terminal SiH, and CE chain extenders terminal SiH only. Specialty XL 2450 and XL 2460 serve polymers with more than 13 mole % phenyl.

XL 10: 7.55 mmole/gm SiH, 45 cSt
XL 1342: hybrid, 8.6 mmole/gm SiH
CE-4: chain extender, 2.90 mmole/gm
XL 2460: high phenyl, 350 cSt

Platinum and Tin Catalysts

Platinum catalysts cure two part RTV formulations: Karstedt catalyst at 20% Pt in VTS or 1 to 3.25% Pt in vinyl polymer, and Ashby catalyst at 2% Pt. Andisil® 782 and 785 cure high phenyl and high refractive index systems, while TL 10 and TL 28 tin catalysts serve condensation cure.

Karstedt: 20.00% Pt in VTS
782: 2.25% Pt, phenyl above 35%
785: 0.50% Pt, high refractive index
TL 10: dibutyltin dilaurate

AS 200 Fumed Silica and Andiform Masterbatch

Andifil AS 200 medium surface fumed silica imparts a significant increase in viscosity in liquid systems, free flow of powders and reinforcement of silicone and organic rubbers. Andiform masterbatches are vinyl silicone polymers compounded with silica for two part RTV formulations.

AS 200: 200 ± 30 m2/g surface area
AS 200: loss on dry ≤ 1.0%
Andiform P 300: 0.06 mmole/g vinyl
Andiform P 1300: 0.045 mmole/g vinyl

SF Fluids and Methyl Phenyl Silicones

Andisil® SF fluids are dimethyl polysiloxanes from 5 cSt to 600,000 cP with thermal stability, water repellency and low surface tension. Methyl phenyl fluids and vinyl polymers with 3 to 42 mole % phenyl raise thermal stability and refractive index.

SF 1,000: 1,000 cSt
SF 600,000: 600,000 cP
SF 1208: 4.2 mole % phenyl, 80 cSt
SF 4565 CV: 42 mole % phenyl, 4,500 cSt

Silanol and Crosslinker for a One Part Sealant

The moisture curing base of a one part RTV sealant is an Andisil® OH silanol polymer; base viscosity is chosen in the OH 750 to OH 300,000 range (750 to 300,000 cP). Low viscosity OH 40 (3.5% silanol) and OH 70 (1.25%) serve as reactive diluents and for filler treatment.

OH polymers contain no plasticizers or additives. Neutral cure uses MOS and VOS oxime crosslinkers or the MT 9010 and VT 6535 blends, acetoxy systems use MTAS, ETAS and the MTAS/ETAS 30/70 blend.

The adhesion promoter is chosen among amino and epoxy silanes (1100, 1120, 187), the condensation catalyst is TL 10 dibutyltin dilaurate or TL 28 dimethyltin dineodecanoate.

Two Part System: Vinyl, SiH and Platinum

The Andisil® VS base polymer for addition cure is chosen by viscosity and vinyl content: VS 200 has 0.25 mmoles/gm at 200 cSt, VS 5,000 has 0.06 mmoles/gm at 5,000 cSt.

The crosslinker is chosen by SiH content, from 0.95 mmole/gm for XL 1B to 7.55 mmole/gm for XL 10; CE-4, CE-13 and CE-500 chain extenders carry terminal SiH only.

Karstedt catalyst comes at 20% Pt in VTS or at 1 to 3.25% Pt in 200, 500 and 1000 cSt vinyl polymer, and customized platinum content and polymer viscosity are available. Durometer and crosslinking density are adjusted with specialty vinyl polymers and VQM resins.

VS, XL and CE grades are offered in EU compliant versions with less than 0.1% D4 to D6.

Phenyl and Clear Formulations

The refractive index of methyl phenyl silicones increases with phenyl concentration: SF 1421 with 3.0 mole % has 1.415, SF 2465 CV with 42.0 mole % has 1.54.

Phenyl contents of 3 to 8 mole % raise low temperature flexibility, higher contents raise high temperature thermal stability, and high phenyl grades are used for index matching and clarity.

Polymers with more than 13 mole % phenyl need the specialty crosslinkers XL 2450, XL 2460 and XL 245 PT, polymers above 35% phenyl by weight need Andisil® 782 catalyst (2.25% Pt), and high refractive index formulations use 785 (0.50% Pt).

Unfilled phenyl RTV has poor mechanical properties, so fillers and the MVT 152 and MVT 154 additives are added.

Silanes and Additives for Coatings

For coatings the manufacturer lists amino, epoxy, methacryloxy, sulfur and vinyl silanes, oximes, silicone fluids and polyethers.

Andisil® SP silicone polyethers act as emulsifiers, foaming agents, solubilizers and softeners and add leveling, slip and mar resistance to coatings; SP 1818 (HLB 7.0, 2,500 cP) increases gloss.

D4, D5 and D6 cyclics and volatile fluids are exempt from VOC regulations and reduce the overall VOC concentration of a formulation. MH 20 and MH 30 methyl hydrogen fluids keep powders dry and act as an anti-caking material.

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