Crosslinkable silicone mixtures containing a guanidine catalyst and an adhesion promoter

Patent metadata

Field	Value
Publication number	US-10947431-B2
Application number	US-201716345763-A
Country	US
Kind code	B2
Filing date	Nov 9, 2017
Priority date	Nov 11, 2016
Publication date	Mar 16, 2021
Grant date	Mar 16, 2021

Abstract

A crosslinkable silicone composition including: a. at least one condensation-crosslinkable polydiorganosiloxane P having silanol, alkoxysilyl, carboxysilyl, ketoximinosilyl, amidosilyl and/or aminosilyl end groups; b. at least one silane or siloxane crosslinker V for the condensation-crosslinkable polydiorganosiloxane; c. at least one crosslinking catalyst K1 of the general formula (I)

d. at least one adhesion promoter H of the general formula (IV).

Compositions of this kind are especially suitable as adhesives, sealants, coatings or casting compounds and are notable for a low tendency to separate and very good adhesion under moist and warm conditions.

First claim

The invention claimed is:

1. A crosslinkable silicone composition comprising
a. at least one condensation-crosslinkable polydiorganosiloxane P having silanol, alkoxysilyl, carboxysilyl, ketoximinosilyl, amidosilyl and/or aminosilyl end groups;
b. at least one silane or siloxane crosslinker V for the condensation-crosslinkable polydiorganosiloxane;
c. at least one crosslinking catalyst K1 of the general formula (I)

where Z 1 and Z 2 independently represent H or linear or branched oligodiorganylsiloxanes of the general formulae (II) and (III), and

where index n represents an integer value from 1 to 400; index m represents an integer value of 1, 2 or 3; index o represents an integer value from 0 to 10; and
the R 5 to R 10 radicals independently represent a monovalent aliphatic linear or branched C1 to C8 alkyl radical which optionally contains ring structures and/or heteroatoms selected from the group of halogens, N, O, P and S;
the R 4 radical independently represents a divalent aliphatic linear or branched C1 to C8 alkyl radical which optionally contains ring structures and/or heteroatoms selected from the group of halogens, N, O, P and S; and
the R 1 to R 3 radicals independently represent a hydrogen atom or an aliphatic linear or branched C1 to C8 alkyl radical which optionally contains ring structures and/or heteroatoms selected from the group of halogens, N, O, P and S, where the R 1 to R 3 radicals may be joined to form one or two aliphatic or aromatic rings and the guanidine of the formula (I) may optionally be in protonated form;
wherein at least one Z 1 or Z 2 is a linear or branched oligodiorganylsiloxane of the formula (II) or formula (III);
d. a metal catalyst K2, the catalyst K2 comprising an element selected from groups 4, 8, 12, 13 and 15 of the Periodic Table of the Elements; and
e. at least one adhesion promoter H of the general formula (IV)

where indices q, r and s independently represents an integer value from 0 to 10, wherein a sum total of q+r≥1;
the R 11 radicals are independently a monovalent linear or branched C1-C21 alkyl radical which may be substituted by one or more heteroatoms selected from the group of B, N, O, Si, S and P and/or may contain aliphatic or aromatic cycles and/or may contain double bonds;
the R 12 radicals are independently a monovalent linear or branched C3-C21 alkyl radical which may be substituted by one or more heteroatoms selected from the group of B, N, O, Si, S and P and/or may contain aliphatic or aromatic cycles and/or may contain double bonds;
the R 13 radicals are independently a hydrogen atom or an R 11 radical;
the R 14 radicals are independently a divalent linear or branched C1-C21 alkyl radical which may be substituted by one or more heteroatoms selected from the group of B, N, O, Si, S and P and/or may contain aliphatic or aromatic cycles and/or may contain double bonds;
wherein the adhesion promoter H has been prepared from at least one epoxide and at least one amine that have been used in a molar ratio of epoxy groups to amine groups of 1:1 to 2:1.

2. The silicone composition as claimed in claim 1 , wherein the polydiorganosiloxane P has silanol, methoxysilane, ethoxysilane or acetoxysilane end groups.

3. The silicone composition as claimed in claim 1 , wherein the composition is free of organotin compounds.

4. The silicone composition as claimed in claim 1 , wherein the silane or siloxane crosslinker V for the condensation-crosslinkable polydimethylsiloxane comprises at least one tri- or tetrafunctional silane or hydrolyzates, partial hydrolyzates and/or condensates thereof.

5. The silicone composition as claimed claim 1 , wherein the adhesion promoter H contains at least one alkoxysilane group.

6. The silicone composition as claimed in claim 1 , wherein the adhesion promoter H has been prepared from at least one epoxysilane and at least one amine or at least one aminosilane and at least one epoxide.

7. The silicone composition as claimed in claim 1 , wherein the adhesion promoter H has been prepared from at least one epoxysilane and at least one aminosilane.

8. The silicone composition as claimed in claim 1 , wherein the adhesion promoter H is present in the composition in an amount of between 0.5% and 2.5% by weight, based on the overall composition.

9. The silicone composition as claimed in claim 1 , wherein the composition is a two-component silicone composition consisting of a polymer component A comprising
the at least one reactive polydiorganosiloxane polymer P,
optionally a filler F, which may optionally be hydrophobized, and
optionally at least one plasticizer;

and a hardener component B comprising
the at least one crosslinker V for polydiorganosiloxanes,
the catalyst K1,
the metal catalyst K2,
the adhesion promoter H,
optionally a filler F, which may optionally be hydrophobized, and
optionally at least one plasticizer.

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

11. A built construction or fabricated article that has been bonded, sealed, cast or coated with a silicone composition as claimed in claim 1 .

12. A method for improving the adhesion of a two-component silicone composition, comprising adding to a two-component silicone composition:
a. at least one crosslinking catalyst K1 of the general formula (I)

where Z 1 and Z 2 independently represent H or linear or branched oligodiorganylsiloxanes of the general formulae (II) and (III), and

where index n represents an integer value from 1 to 400; index m represents an integer value of 1, 2 or 3; index o represents an integer value from 0 to 10; and
the R 5 to R 10 radicals independently represent a monovalent aliphatic linear or branched C1 to C8 alkyl radical which optionally contains ring structures and/or heteroatoms selected from the group of halogens, N, O, P and S;
the R 4 radical independently represents a divalent aliphatic linear or branched C1 to C8 alkyl radical which optionally contains ring structures and/or heteroatoms selected from the group of halogens, N, O, P and S; and
the R 1 to R 3 radicals independently represent a hydrogen atom or an aliphatic linear or branched C1 to C8 alkyl radical which optionally contains ring structures and/or heteroatoms selected from the group of halogens, N, O, P and S, where the R 1 to R 3 radicals may be joined to form one or two aliphatic or aromatic rings and the guanidine of the formula (I) may optionally be in protonated form;
wherein at least one Z 1 or Z 2 is a linear or branched oligodiorganylsiloxane of the formula (II) or formula (III); and
b. a metal catalyst K2, the catalyst K2 comprising an element selected from groups 4, 8, 12, 13 and 15 of the Periodic Table of the Elements; and
c. at least one adhesion promoter H of the general formula (IV)

where indices q, r an

Assignees

• Sika Tech Ag

Inventors

• Jakob Samuel
• Friedel Manuel

Classifications

• C09J183/04 Primary

  Polysiloxanes · CPC title

• C08G77/388

  containing nitrogen · CPC title

• C08G77/16

  to hydroxy groups · CPC title

• C09J11/06

  organic · CPC title

• C09D183/04

  Polysiloxanes · CPC title