Silane Terminated Polyurethanes 2009-09-07

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Silane Terminated Polyurethanes

Edition: September 2009

ContentComparison PUR and STP chemistryCrosslinking mechanism Design of PUR polymers Design of STP polymers Properties of STPs

Synthetic routes to STPsAminosilane route NCO-silane Route Comparison aminosilane route vs. NCO-silane route

Comparison STPs vs. MS-PolymersChemical Differentiation Advantages of STPs

Product range and formulation examplesProduct portfolio STPs Formulation portfolio and application range Formulation processDr. Beate Baumbach 2009-09-07 Seite 2

Comparison of PUR and STP Chemistry Crosslinking Mechanism PUR PURNCO

STP STPH2O OCH3 Si OCH3 OCH3 CH3O CH3O Si CH3O + H2O - HOCH3 OCH3 OCH3

+

- CO2 NH2

+OCN

O C N H

=

Si N H OCH3

Si O CH3O

Dr. Beate Baumbach 2009-09-07 Seite 3

Comparison of PUR and STP Chemistry Design of PUR PolymersPolyurethane Polymers (moisture curing)HO4k-polyether

OH

HO

6k-polyether

OH

OH

OCN

NCO

OCN OCN NCO

NCOR-NCO + OCN-R - CO2 O R-N H + H2O

= N-R H

NCO

Dr. Beate Baumbach 2009-09-07 Seite 4

Comparison of PUR and STP Chemistry Design of PUR PolymersPolyurethane Polymers (moisture curing)HO HO OH OH PUR prepolymer approach allows to use low viscosity polymers PUR prepolymer approach allows to use low viscosity polymers OH and to adjust final crosslinking density by the ratio of bi- and and to adjust final crosslinking density by the ratio of bi- and NCO trifunctional OCN trifunctionalpolyethers polyethers4k-polyether 6k-polyether

Soft elastic PUR prepolymers mainly build up linear molecular Soft elastic PUR prepolymers mainly build up linear molecular OCN NCOOCN

weight !! weight

R-NCO + OCN-R

NCO- CO2 O R-N H + H2O

= N-R H

NCO

Dr. Beate Baumbach 2009-09-07 Seite 5

Comparison of PUR and STP Chemistry Design of STP PolymersSilane-Terminated Polyurethane PolymersHOAcclaim Polyether

OH

OCN

NCO

OMe H2NSi

OMe OMe

MeO MeO MeOSi Si

OMe OMe OMe

OCH3 CH3O Si OCH3 + CH3O Si OCH3 CH3O

+ H2O - HOCH3

Si

OCH3 CH3O Si O OCH3 CH3O

= Si-O-Si Cluster

Dr. Beate Baumbach 2009-09-07 Seite 6

Comparison of PUR and STP Chemistry Design of STP PolymersSilane-Terminated Polyurethane PolymersHO

STPs are multifunctional, they crosslink by curing and cannot STPs are multifunctional, they crosslink by curing and cannot build up linear molecular weight build up linear molecular weight Si HN OMe2

Acclaim Polyether

OH

OCN

NCO

OMe

OMe MeO MeO

Polymer chain length determines the distance between two OMe Polymer chain length determines the distance between twoSi Si

crosslinking points crosslinking points MeO

OMe OMe

Therefore products for soft applications have a high viscosity Therefore products for soft applications have a high viscosityOCH3 CH3O Si OCH3 + CH3O Si OCH3 CH3O + H2O - HOCH3 Si OCH3 CH3O Si O OCH3 CH3O

= Si-O-Si Cluster

Dr. Beate Baumbach 2009-09-07 Seite 7

Comparison of PUR and STP Chemistry Properties of STPsSTPs combine positive properties of PUR Tailored systems by use of PU building blocks Good cohesion Paintability and Silicones: Bubble free curing (even in thick layers) Good adhesion Free of isocyanates

Dr. Beate Baumbach 2009-09-07 Seite 8

Synthetic Routes to STPs Aminosilane Route

HO

P o ly e th e r

OH

Broad molecular weight distribution Strong hydrogen bridges

OCN

R

NCO

OCN

P o ly u r e th a n e

NCO

HRN

OMe OMe Si OMe O

O MeO MeO Si MeO N R N H P o ly u re th a n e N H

N R

Si

OMe OMe OMe

Dr. Beate Baumbach 2009-09-07 Seite 9

Synthetic Routes to STPs NCO-silane Route

HO

Polyether

OH

Narrow molecular weight distributionOMe Si OMe OMe O

OCN

Weak hydrogen bridges

O MeO MeO Si MeO N H O Polyether O

N H

OMe Si OMe OMe

Dr. Beate Baumbach 2009-09-07 Seite 10

Synthetic Routes to STPs Comparison Aminosilane Route vs. NCO-silane RouteThe two routes to STPs give different product properties: a) Aminosilane route: Higher viscosity (dispersity / H-bridges) Higher modulus (H-bridges)

b) NCO-silane route: Lower viscosity Lower modulus

Dr. Beate Baumbach 2009-09-07 Seite 11

Comparison STPs vs. MS-Polymers Chemical DifferentiationSilane terminated PolyurethanesR R RSi

RPolyurethane BackboneSi

- Polyurethane backboneR

R

- 3 reactive goups at each end

Silane terminated Polyols (MS-Polymer)CH 3 CH 3Polyether BackboneSi

R R

Si

R R

- Polyether backbone - 2 reactive groups at each end

R = OCH3

Dr. Beate Baumbach 2009-09-07 Seite 12

Comparison STPs vs. MS-Polymers Advantages of STPs Polyurethane backbone vs. polyether backbone Better mechanical propertiesHigher elastic recovery / better creep resistance

Trifunctional silanes vs. difunctional silanes Faster cureLower catalyst level needed Use of amine instead of tin catalyst possible !!!

Polyurethane backbone + silicone endcapping Improved adhesion Big variety of building blocks and synthetic routs More freedom in polymer design & range of applicationsTaylor-made products (molecular weight, functionality, type of PIC) Low and medium modulus range, sealants & adhesives

Dr. Beate Baumbach 2009-09-07 Seite 13

Product Range and Formulation Examples Product Portfolio STPsViscosity at 23 C [mPas] Molecular weight [kg/mol]

Product

Delivery form

Remarks STP with high viscosity, for hard formulations with high modulus and medium elongation STP with high viscosity, for soft" formulations with low modulus and high elongation STP with low viscosity, for hard" formulations with high modulus and low elongation

Desmoseal S XP 2458

90 % in Mesamoll

30,000 - 40,000

approx. 20

Desmoseal S XP 2636

100%

32,000 - 42,000

approx. 24

Desmoseal S XP 2749

100%

approx. 5,000

approx. 13

Desmoseal S XP 2458

Desmoseal S XP 2636 Desmoseal S XP 2749

Dr. Beate Baumbach 2009-09-07 Seite 14

Product Range and Formulation Examples Formulation Portfolio and Application Range

Technical Sealant Construction Sealant < 30 40 50 Elastic Adhesive 60 70

Structural Adhesive

Shore A

Dr. Beate Baumbach 2009-09-07 Seite 15

Product Range and Formulation Examples Formulation Portfolio and Application RangeDesmoseal S XP 2636 Shore A 20 - A 70 - 1K SEA - 1K SEA Sprayable - 1K ADH - 1K ADH Flooring - 1K ADH Transparent Desmoseal S XP 2458 Shore A 40 - A 80 - 1K SEA Sprayable - 1K ADH - 1K ADH Flooring - 1K ADH Transparent - 2K ADH Desmoseal S XP 2749 Shore A 65 - 80 - 1K ADH - 1K ADH Flooring

Technical Sealant Construction Sealant < 30 40 50 Elastic Adhesive 60 70

Structural Adhesive

Shore A

Dr. Beate Baumbach 2009-09-07 Seite 16

Product Range and Formulation Examples Formulation Portfolio and Application RangeProperty range of sealants and elastic adhesives: Tensile strength Elongation at break Shore A Modulus@100% 2.0 6.5 MPa 100 1,000 % 20 - 80 0.3 3.0 MPa

STPs provide superior properties compared to difunctional hybrid polymers

Dr. Beate Baumbach 2009-09-07 Seite 17

Product Range and Formulation Examples Formulation ProcessPolymer Formulation Application

Parquet Adhesive

Sealant

Seam Sealer

Elastic Adhesive

Dr. Beate Baumbach 2009-09-07 Seite 18

Product Range and Formulation Examples General Remarks Formulation ProcessFor the production of all formulations a double-walled vacuum dispenser with side scraper is recommended. Process 1: Physical pre-drying of fillers (preferred method) Use physically pre-dried fillers (e.g. 16 h at 100 C) Add low amount of water scavanger to obtain storage stability Low VOC content Process 2: Chemical drying of the formulation Use of fillers which are not pre-dried Add higher amount of water scavanger to obtain storage stability High emissions of methanol possible

Dr. Beate Baumbach 2009-09-07 Seite 19

Product Range and Formulation Examples Formulation Process for 1 kg BatchesStep 1: The vessel is filled with binder, plasticizer, additives (e.g. antioxidants), pigments and thixotropic agent . The filler is added under stirring in 2 - 3 portions. Catalyst and water scavenger are added together with the last one. Then the premix is dispersed under stirring and cooling (temperature: < 60 C) and static vacuum (< 200 mbar) for: - 10 minutes at 3,000 rpm and - 10 minutes at 1,000 rpm Finally the water content of the premix should be < 200 ppm.

Dr. Beate Baumbach 2009-09-07 Seite 20

Product Range and Formulation Examples Formulation Process for 1 kg BatchesStep 2: The adhesion promotors (e.g. amino silanes) are added to the premix under stirring and cooling (temperature: < 60 for: C) -10 minutes under static vacuum (< 200 mbar) at 1,000 rpm and - 5 minutes under dynamic vacuum at 1,000 rpm The final mixture is filled into plastic cartridges or inside coated aluminium cartridges.

Dr. Beate Baumbach 2009-09-07 Seite 21

Product Range and Formulation Examples General Remarks Formulation ProcessImportant points: A temperature of 70 should not be exceeded, othe rwise a negative C impact on the final properties can be noticed The amount of water is crucial for the storage stability of the formulation The water scavanger (e.g. vinyltrimethoxysilane) has a low boiling point and might evaporate during the process Use of vacuum needs to be controlled

Dr. Beate Baumbach 2009-09-07 Seite 22

Product Range and Formulation Examples Summary Formulation ProcessMechanical properties: Polymer Plasticiser Filler Aminosilanes Viscosity / Rheology: Thixotropic agent Plasticiser Filler Solvents

Adhesion properties: Aminosilanes Plasticiser Amount of catalyst Light stabilisersDr. Beate Baumbach 2009-07-07 Seite 23

Storage stability: Moisture content Amount of water scavanger Aminosilanes

Thank you for your attention

Dr. Beate Baumbach 2009-09-07 Seite 24

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