Fast curing two-component silicone composition having adjustable pot life

Patent metadata

Field	Value
Publication number	US-12415924-B2
Application number	US-202117786808-A
Country	US
Kind code	B2
Filing date	Jan 20, 2021
Priority date	Feb 3, 2020
Publication date	Sep 16, 2025
Grant date	Sep 16, 2025

Abstract

A two-component silicone composition made of a component A including a hydroxyl-group terminated polydiorganosiloxane P; between 0.05-5.0 wt. % water, relative to component A; and component B including a non-condensable polydiorganosiloxane; a catalyst K cross-linking polydiorganosiloxanes; between 0-50 wt. % of a first organosilane V1 according to formula (I), between 2-60 wt. % of a second organosilane V2 according to formula (II), up to 25 wt. % of organosilanes V3 having hydrolyzable alkoxysilane groups Si—ORa not falling under the formulae (I) and (II), with Ra being a hydrogen atom or monovalent, linear or branched alkyl group with 1-6 carbon atoms, Rb being a divalent, linear or branched alkyl group or alkenyl group with 2-20 carbon atoms, and Rc being a divalent, linear or branched alkyl group with 2-20 carbon atoms containing a secondary amino group; the composition containing less than 10 mole-%, relative to the amount of organosilane V2, of organosilanes with epoxy groups.

First claim

The invention claimed is:

1. A two-component silicone composition consisting of a component A comprising
i) at least one hydroxyl group-terminated polydiorganosiloxane P;
ii) between 0.05% and 5.0% by weight of water, based on component A; and a component B comprising
i) at least one noncondensable polydiorganosiloxane as plasticizer;
ii) at least one catalyst K for the crosslinking of polydiorganosiloxanes;
iii) between 0% and 50% by weight, based on component B, of at least one first organosilane V1 of formula (I)

iv) between 2% and 60% by weight, based on component B, of at least one second organosilane V2 of formula (II)

v) up to 25% by weight, based on component B, of further organosilanes V3 having hydrolyzable alkoxysilane groups Si—OR a that are not covered by the formulae (I) and (II),
where R a is a hydrogen atom or a monovalent linear or branched alkyl radical having 1 to 6 carbon atoms,
R b is a divalent linear or branched alkyl radical or alkenyl radical having 2 to 20 carbon atoms, and
R c is a divalent linear or branched alkyl radical which has 2 to 20 carbon atoms and contains at least one secondary amino group and optionally a hydroxyl group and an ether oxygen;
with the proviso that the composition contains less than 10 mol %, based on the amount of organosilane V2, of organosilanes having epoxy groups,
wherein the organosilane V2 is at an organosilane of formula (IIa)

where R d is a divalent linear or branched alkyl radical which has 2 to 10 carbon atoms and optionally contains a hydroxyl group and an ether oxygen, and
R e is a divalent linear or branched alkyl radical having 2 to 10 carbon atoms, and

wherein the organosilane V2 is a mixture of:
an organosilane V2a in which the R d and R e radicals in formula (IIa) are both a divalent linear or branched alkyl radical having 2 to 10 carbon atoms; and
an organosilane V2b in which the R e radical in formula (IIa) is a divalent linear or branched alkyl radical having 2 to 10 carbon atoms, and R d radical is a divalent linear or branched alkyl radical having 2 to 10 carbon atoms, and additionally one of the two structural elements shown in formula (IIb),

where the organosilanes V2a and V2b mentioned are present in component B in a weight ratio of between 1:2 and 2:1.

2. The two-component silicone composition as claimed in claim 1 , wherein the hydroxyl group-terminated polydiorganosiloxane P is a polydiorganosiloxane P′ of the formula (I)

where
the R 1 and R 2 radicals are independently linear or branched, monovalent hydrocarbyl radicals which have 1 to 12 carbon atoms and optionally include one or more heteroatoms, and optionally one or more C—C multiple bonds and/or optionally cycloaliphatic and/or aromatic components; and
n is chosen such that the weight-average molecular weight M w of the polydiorganosiloxane P′ relative to polystyrene is 500 to 250,000 g/mol.

3. The two-component silicone composition as claimed in claim 2 , wherein the hydroxyl group-terminated polydiorganosiloxane P′ is a polydiorganosiloxane P1 of the formula (I) where n is chosen such that the weight-average molecular weight M w of the polydiorganosiloxane P1 relative to polystyrene is 30,000 to 80,000 g/mol; or
in that the polydiorganosiloxane P′ used is a mixture of
i″) at least one hydroxyl group-terminated polydiorganosiloxane P2 of the formula (I) where n is chosen such that the weight-average molecular weight M w of the polydiorganosiloxane P2 relative to polystyrene is >80,000 to 250,000 g/mol; and
ii″) at least one hydroxyl group-terminated polydiorganosiloxane P3 of the formula (I) where n is chosen such that the weight-average molecular weight M w of the polydiorganosiloxane P3 relative to polystyrene is 500 to ≤80,000 g/mol.

4. The two-component silicone composition as claimed in claim 2 , wherein the R 1 and R 2 radicals are alkyl radicals having 1 to 5 carbon atoms.

5. The two-component silicone composition as claimed in claim 1 , wherein organosilane V3 is a silane of the formula (III)

where the R 3 radical is independently a linear or branched, monovalent hydrocarbyl radical which has 1 to 12 carbon atoms and optionally includes one or more heteroatoms, and optionally one or more C—C multiple bonds and/or optionally cycloaliphatic and/or aromatic components;
the R 4 radical is an R a radical; and
p has a value of 0 to 4, with the proviso that, if p has a value of 3 or 4, at least p-2 R 3 radicals each have at least one group reactive, with the hydroxyl groups of the polydiorganosiloxane P.

6. The two-component silicone composition as claimed in claim 1 , wherein the R a radicals in all organosilanes V1, V2 and V3 is an alkyl radical having 1 to 5 carbon atoms, where portions of these R a radicals after hydrolysis of Si—OR a groups may be replaced by hydrogen atoms.

7. The two-component silicone composition as claimed in claim 1 , wherein the catalyst K is an organotin compound.

8. The two-component silicone composition as claimed in claim 1 , wherein organosilane V2 comprises an organosilane V2a, and in that the catalyst K is present in component B in an amount between 0.1% by weight and 2% by weight, based on component B.

9. The two-component silicone composition as claimed in claim 1 , wherein the weight ratio of component A to component B is ≥1:1.

10. A method comprising applying a two-component silicone composition as claimed in claim 1 as adhesive, sealant, coating or as casting compound.

11. A cured silicone composition, wherein it is obtainable from a two-component silicone composition as claimed in claim 1 by mixing component A with component B.

12. A method of adjusting pot life with the same mechanical properties after curing of a two-component silicone composition as claimed in claim 1 , wherein the mixing ratio of component A to component B based on weight is selected arbitrarily within the range of component A to component B from 1:1 to 25:1.

13. The two-component silicone composition as claimed in claim 1 , wherein the water of component A is part of a water/oil emulsion including 40% to 60% by weight of water, based on the emulsion.

Assignees

• Sika Tech Ag

Inventors

• Schlumpf Michael
• Suter Riccardo
• Jakob Samuel

Classifications

• C08G2190/00

  Compositions for sealing or packing joints · CPC title

• C08G2170/00

  Compositions for adhesives · CPC title

• C08G2150/00

  Compositions for coatings · CPC title

• C08G77/16

  to hydroxy groups · CPC title

• C09J183/04

  Polysiloxanes · CPC title