EP3735447A1

EP3735447A1 - Silicone sealant having adjustable flow properties

Info

Publication number: EP3735447A1
Application number: EP18822400.0A
Authority: EP
Inventors: Manuel Friedel
Original assignee: Sika Technology AG
Current assignee: Sika Technology AG
Priority date: 2018-01-03
Filing date: 2018-12-21
Publication date: 2020-11-11
Also published as: US20210062001A1; CN111770977B; WO2019134863A1; CN111770977A

Abstract

The invention relates to a single-component, moisture-hardening silicone composition comprising 100 parts by weight of a crosslinkable polydiorganosiloxane OH-PDMS having silanol end groups, 5 to 20 parts by weight of at least one hydrophilic silicic acid KS, 1 to 10 parts by weight of at least one organoalkoxysilane or organoalkoxysiloxane crosslinker V, which contains at least 2 alkoxysilane groups, 1 to 7 parts by weight of an organoalkoxysilane or organoalkoxyiloxane AS, which contains at least one amino alkyl group having a primary amino group, 0.1 to 7 parts by weight of at least one tin catalyst K, up to 5 parts by weight of an organoalkoxysilane or organoalkoxysiloxane OS, which contains at least two alkoxysilane groups, wherein the silicone composition contains less than 1.0 wt% water, relative to the total composition, provided that the reactivity for hydrolysis of the organoalkoxysilane or organoalkoxysiloxane OS is higher than the reactivity for hydrolysis of the organoalkoxysilane or organoalkoxysiloxane crosslinker V. The single-component composition is suitable as a low-modulus adhesive or sealant and as a coating or casting compound and can be formulated either as a self-leveling or as a stable composition.

Description

Silicone sealant with adjustable flow behavior

Description Technical area

The invention relates to a one-component moisture-curing

Silicone composition, a method of bonding or grouting with the composition and its use.

State of the art

Silicones are known compositions which have long been used as adhesives or sealants. Such silicones can be designed as one- or two-component silicone formulations and contain as main components a polyorganosiloxane and a crosslinker. It is between cold-curing RTV silicones (RTV = raumtemperaturvernetzend or -Vulkanisierend) and hot-crosslinking HTV silicones (HTV =

high temperature crosslinking or vulcanizing). One- and two-component RTV silicones are also referred to as RTV-1 silicones and RTV-2 silicones, respectively.

RTV-1 silicones have long been known. It is also known that such

Curing formulations based on so-called neutral crosslinking. Classically, neutral crosslinking systems

Oxime compounds free, the smell is perceived as very unpleasant and are harmful to health. Alternatively, RTV-1 silicones can be formulated with alkoxy group-containing crosslinkers. Cleavage products of the crosslinking are then alcohols whose odor is significantly less unpleasant. In general, the crosslinkers used are monomeric silanes.

It is also known that the addition of hydrophilic (uncoated), mostly fumed silica increases the viscosity of silicone compositions, especially at low shear rates until dormant. This effect is especially noticeable when silicone-terminated silicone polymers are used.

This increase in viscosity at rest is stable

Compositions are desirable where thixotropic behavior prevents sagging of the applied compositions on sloping or vertical surfaces. However, this also causes problems in certain

Applications. In the case of very thin adhesive gaps or joints, low-viscosity or even self-leveling compositions are preferred, since they fill out small volumes significantly better and increase the contact area. The same applies to potting compounds and coatings, where likewise stability is undesirable.

One way to self-leveling properties

To achieve and to adjust silicone compositions on a limited scale is on the one hand the use of short-chain silicone polymers of low viscosity as binders and on the other hand the use of larger amounts of silicone plasticizers. Silicone plasticizers may be unreactive, but this increases the risk of emigration or bleeding of the plasticizers, and thus, e.g. promotes the formation of persistent stains in the adhesive substrate. Reactive plasticizers and the above-mentioned short-chain silicone polymers, however, often lead to an increase in the modulus of the compositions and thus embrittlement, which significantly limits the use as a low modulus sealant.

Another possibility to increase the self-leveling properties of filled RTV-1 silicone compositions significantly without having to use high amounts of plasticizers is taught in WO 2013/022532 A1. Through the use of "masked" silicone polymers, for example

Silicone polymers with alkoxysilane end groups, as well as from

surface-treated, hydrophobized silica as filler, good self-leveling properties are achieved. However, this method has some disadvantages. For example, the choice of silicone polymers is more expensive, end-capped silicone polymers are limited and the flow properties of the composition can not be influenced and, for example, adjusted to desired viscosity values or thixotropic ability. Furthermore, this teaching is particularly suitable for Ketoximvernetzer, which is less preferred for health reasons.

US5017628 also describes a self-leveling

Silicone composition, which is suitable as a low modulus sealant and in addition to a silicone polymer with hydroxyl end groups in addition

Silicone softener, Siloxanvernetzer, a diacetamido-functional silane and a hydrophobized, surface-treated filler contains. Disadvantageous are the mandatory use of the diacetamido-functional silane and the necessity that the filler must be hydrophobic. Also missing here is the ability to adjust the extent of the flow properties.

There is therefore a need for an RTV-1 silicone composition which does not possess the aforementioned disadvantages, but nevertheless

has self-leveling properties and can be used as a low modulus sealant class 20 (LM or HM, type F or G) according to ISO 1600. Furthermore, there is a need to

Flow properties and thus the extent of self-leveling

Behavior of such a composition by the relative amount of certain components to be able to adjust.

Presentation of the invention

The object of the present invention is therefore to provide a one-component moisture-curing silicone formulation which can be formulated oxime-free with customary silicone polymers having hydroxyl end groups (silanol end groups) and hydrophilic silica fillers without surface modification, and conventional silane or siloxane crosslinkers, but nevertheless has adjustable self-leveling properties, none Has plasticizer emigration and which can be used as a low modulus sealant.

It has surprisingly been found that by using up to 5 parts by weight of a highly reactive organoalkoxysilane or siloxane in a silicone composition comprising 100 parts by weight of a

silanol endblocked polydiorganosiloxane, 5 to 20

Parts by weight of a hydrophilic silica, 1 to 10

Parts by weight of a less reactive organoalkoxysilane or siloxane crosslinker, 1 to 7 parts by weight of an organoalkoxysilane or

Organoalkoxysiloxane containing at least one aminoalkyl group having a primary amino group and 0.1 to 7 parts by weight of a

Tin catalyst the flow properties of the composition can be adjusted and optionally self-leveling properties can be achieved. When the composition is free from the highly reactive

Organoalkoxysilane or siloxane is or only very small proportions, e.g. to 1 part by weight thereof, the composition is self-leveling. At higher levels, e.g. between 1 and 5 parts by weight, the

The higher the proportion of highly reactive organoalkoxysilane or siloxane in the composition, the more stable the composition.

The composition according to the invention can be formulated as a self-leveling or stable composition and has excellent mechanical properties making it suitable as a low-modulus sealant of class 20 (LM or HM, type F or G) according to ISO 1600.

Further aspects of the invention are the subject of further independent claims. Particularly preferred embodiments of the invention are the subject of the dependent claims. Way to carry out the invention

The present invention relates to a one-component moisture-curing silicone composition comprising

a) 100 parts by weight of at least one crosslinkable

Polydiorganosiloxane OH-PDMS with silanol end groups, which at 23 ° C has a viscosity of 1 Ό00 to 350Ό00 mPa · s, measured according to DIN EN ISO 3219;

b) 5 to 20 parts by weight of at least one hydrophilic silica KS; c) 1 to 10 parts by weight of at least one organoalkoxysilane or organoalkoxysiloxane crosslinker V, which is at least 2

Alkoxysilane groups;

d) 1 to 7 parts by weight of an organoalkoxysilane or

Organoalkoxysiloxane AS, which is at least one

Aminoalkyl group having a primary amino group; e) 0.1 to 7 parts by weight of at least one tin catalyst K;

f) up to 5 parts by weight of an organoalkoxysilane or

Organoalkoxysiloxane OS, which is at least two

Alkoxysilane groups;

wherein the silicone composition less than 1.0 wt .-% water, preferably less than 0.5 wt .-% water, in particular less than 0.1 wt .-% water, based on the total composition, with the proviso that the reactivity for the hydrolysis of the Organoalkoxysilane or organoalkoxysiloxane OS is higher than the reactivity for hydrolysis of the organoalkoxysilane or organoalkoxysiloxane crosslinker V.

Substance names beginning with "poly", such as, for example, polydimethylsiloxane, refer in the present document to substances which formally contain two or more of the functional groups occurring in their name, such as dimethylsiloxane groups, per molecule.

The term "polymer" in the present document comprises on the one hand a

Collective of chemically unified, but with respect to polymerization degree, molecular weight and chain length differing macromolecules, which was made by a poly-reaction (polymerization, polyaddition, polycondensation) forth. On the other hand, the term also encompasses derivatives of such a collective of macromolecules from polyreactions, compounds which have been obtained by reactions, such as additions or substitutions, of functional groups on given macromolecules and which may be chemically uniform or chemically nonuniform. The term also includes so-called prepolymers, that is, reactive oligo mers pre-adducts whose functional groups are involved in the construction of macromolecules.

"Molecular weight" refers to the molar mass (in grams per mole) of a molecule or moiety. The term "average molecular weight" refers to the number average molecular weight (M _n ) of an oligomeric or poly meric mixture of molecules or molecular residues. It is usually treated by gel permeation chromatography (GPC)

Polydimethylsiloxane determined as standard.

The term "viscosity" refers to the dynamic viscosity or shear viscosity, which is defined by the ratio between the shear stress and the shear rate (velocity gradient) and determined as described in DIN EN ISO 3219. The measurement can be carried out by means of a cone-plate viscometer MCR101 from Anton Paar, Austria, with a cone type CP 25-1 at 23 ° C. Unless stated otherwise, the viscosity values given refer to a shear rate of 0.5 s ^-1 .

As a "storage stable" or "storable" is a substance or a composition tion is called if they at room temperature in a suitable Ge binding for a long time, typically for at least 3 months to 6 months and more, can be stored without them changed in their application or use properties by storage in a relevant for their use to the extent. The terms "mass" and "weight" are used interchangeably throughout this document. Thus, a "weight percent" (% by weight) refers to a percentage by weight which, unless otherwise stated, refers to the mass (weight) of the total composition, or to the context of the entire molecule.

The term "room temperature" refers to a temperature of 23 ° C.

All industry standards and standards referenced in this document refer, unless otherwise indicated, to the version valid at the time of filing the initial application.

A silane in this document is a silicon compound consisting of a silicon atom and 4 functional groups or atoms attached thereto. A siloxane is a compound that has at least two over one

Oxygen atom bridged silicon atoms comprises. Siloxanes are thus condensation products of silanes.

An organosilane is a monomeric silicon compound having at least one nonhydrolyzable group linked via a Si-C bond. An organosiloxane is a compound obtainable from the condensation of at least two organosilanes.

An alkoxysilane is a monomeric silane having at least one alkoxy group attached to the Si atom. A trialkoxysilane and a tetraalkoxysilane are a monomeric silane having three or four alkoxy groups attached to the Si atom. The alkoxy group may e.g. be a Ci-C6 alkoxy group. An alkoxysiloxane is a compound obtainable from the condensation of at least two alkoxysilanes but still after condensation

has at least one alkoxy group.

An organoalkoxysilane is a monomeric silane having at least one

Alkoxy group and at least one non-hydrolyzable group, over a Si-C bond is linked. An organoalkoxysiloxane is a compound which is obtainable from the condensation of at least two organoalkoxysilanes or at least one alkoxysilane and an organoalkoxysilane but which still has at least one alkoxy group after the condensation.

The one-component moisture-curing silicone composition is in particular an RTV-1 silicone. In such RTV-1 silicones, the curing at room temperature by contact with water, generally by contact with the humidity in the air.

The one-part moisture-curing silicone composition comprises first one or more crosslinkable polydiorganosiloxanes. Such crosslinkable polydiorganosiloxanes are well known to those skilled in the art. The crosslinkable polydiorganosiloxanes have silicon-bonded ones

Hydroxyl groups, ie silanol groups, in particular two or more

Silanolgruppe on which a crosslinking is possible. These silanol groups may be present in a side group or end group of the polydiorganosiloxane, with terminal hydroxyl groups being preferred. Such

Silanol-terminated polydiorganosiloxanes are also referred to as a, w-functional polydiorganosiloxanes.

The hydroxyl groups on the polymers, more particularly the silanol groups, can react with the alkoxy groups of the crosslinker or other silanes or siloxanes in the composition to form a bond. This bond is formed in a condensation reaction, whereby by-products such as water or alcohol are usually released. It may be and is even likely that the alkoxysilane first hydrolyzes to a silanol before condensation takes place. These reactions take place preferentially and much more efficiently under the influence of a catalyst, which is also present in the composition according to the invention. This will be described below. The viscosity of the polydiorganosiloxanes may vary depending on the purpose in a wide range. The polydiorganosiloxane used according to the invention can have, for example, a viscosity of from 1 Ό00 to 350Ό00 mPa · s, preferably from 5Ό00 to 120Ό00 mPa · s and particularly preferably from 10Ό00 to 80Ό00 mPa · s, at a temperature of 23 ° C.

Preferably, the polydiorganosiloxane OH-PDMS is a linear one

Polydiorganosiloxane according to formula (I),

wherein the radicals R ¹ , R ² and R ^{3 are} independently linear or branched, monovalent hydrocarbon radicals having 1 to 12 carbon atoms, which optionally one or more heteroatoms, and optionally one or more CC multiple bonds and / or optionally cycloaliphatic and or have aromatic portions;

R ^{4 is} a hydroxyl group;

the index p is a value of 0, 1 or 2; and

the index m is selected such that the polydiorganosiloxane OH-PDMS has a viscosity of from 1 Ό00 to 350Ό00 mPa · s, preferably from 5Ό00 to 120Ό00 mPa · s and particularly preferably from 10Ό00 to 80Ό00 mPa · s, at a temperature of 23 ° C. measured according to DIN 53018.

In the formula (I), the radicals R ¹ and R ² are each independently preferably selected from alkyl groups having 1 to 5, in particular 1 to 3, carbon atoms, such as propyl, ethyl and methyl, wherein methyl is particularly preferred, optionally a part of the alkyl groups, in particular methyl, may be replaced by other groups such as vinyl, phenyl or 3,3,3-trifluoropropyl. In the formula (I), the radical R ³ , if present, independently of each other is preferably selected from phenyl, vinyl or methyl groups. Particularly preferably, the radicals R ¹ , R ² and R ³ in formula (I) are

Methyl groups.

The index m in the formula (I) is selected so that the polydiorganosiloxane has the above viscosity. The subscript m in the formula (I) may be e.g. in the range of 10 to 5000 and preferably 100 to 1500.

The crosslinkable polydiorganosiloxane OH-PDMS is preferably one

crosslinkable polydimethylsiloxane. Preferably used crosslinkable

Polydiorganosiloxanes OH-PDMS are hydroxy terminated linear

Polydiorganosiloxanes, wherein hydroxy-terminated linear polydiorganosiloxanes (a, w-hydroxy-functional polydiorganosiloxanes) are particularly preferred, wherein the polydiorganosiloxane OH-PDMS is preferably a polydimethylsiloxane. The hydroxy-terminated linear polydiorganosiloxanes, in particular polydimethylsiloxanes, preferably have a viscosity, measured to DIN 53018, of from 2300 to 35000 mPa · s, preferably from 5000 to 12000 mPa · s, more preferably from 10Ό00 to 80Ό00 mPa · s, at 23 ° C. s, up. As discussed above, such prior art polydimethylsiloxanes may be modified by partial incorporation of other organic groups rather than methyl.

The composition according to the invention also contains 5 to 20

Parts by weight of at least one hydrophilic silica KS per 100

Parts by weight of polydiorganosiloxane OH-PDMS.

A hydrophilic silica is a solid which consists predominantly of Si (-0) 4 units but may also have silanol groups on the surface and has a three-dimensional, normally porous structure. The term "hydrophilic" indicates that the silica is not surface treated with hydrophobizing additives. Hydrophilic, ie untreated silicic acids are well known to those skilled in the art as fillers and thickeners. You can, for example, over

Precipitation reactions (precipitated silica or precipitated silica) or pyrolysis processes (fumed silica) are produced.

Preferred for the invention is fumed silica, as these

production-related has a lower water content and does not have to be dried. However, precipitated silicas are also suitable.

Particular preference is given to silicas having a BET surface area of from 50 to 300 m ² / g, preferably from 100 to 255 m ² / g.

The composition of the invention further comprises 1 to 10

Parts by weight per 100 parts by weight of polydiorganosiloxane OH-PDMS

at least one organoalkoxysilane or organoalkoxysiloxane crosslinker V which contains at least 2 alkoxysilane groups.

The crosslinker V has at least 2 alkoxysilane groups, preferably at least 3 or more (only in the case of a siloxane, that is to say an oligomeric silane).

Suitable alkoxy groups are, in particular, methoxy, ethoxy, butoxy and propoxy groups. Preference is given to methoxy and ethoxy groups.

The crosslinker V furthermore preferably has 1, 2 or more (only in the case of oligomeric siloxanes) non-hydrolyzable functional groups, in particular alkyl groups or alkenyl groups.

Preferably, the non-hydrolyzable functional groups are selected from methyl, ethyl, vinyl, n-propyl, cyclopentyl, phenyl, cyclohexyl, n-octyl, isooctyl and hexadecyl.

It is also possible to use tetraalkoxysilanes as crosslinker V,

in particular tetraethoxysilane and tetra-n-propoxysilane. Specific examples of monomeric organoalkoxysilane crosslinkers V are

Methyltrimethoxysilane, ethyltrimethoxysilane, vinyltrimethoxysilane,

Phenyltrimethoxysilane, propyltrimethoxysilane, isooctyltrimethoxysilane,

Methylvinyldimethoxysilane or the corresponding compounds in which the methoxy group is replaced by ethoxy or propoxy, such as methyltriethoxysilane, vinyltriethoxysilane, phenyltriethoxysilane, methyltripropoxysilane and phenyltripropoxysilane.

The oligomeric organoalkoxysiloxane crosslinkers V are condensation products of one or more of such monomeric silane crosslinkers, optionally with the use of further silanes, e.g.

Tetraalkoxysilanes. Such oligomeric siloxanes are known and commercially available, for example under the trade name Dynasylan ^® 6490 from Evonik Degussa GmbH.

Oligomers of functional silanes are complex

three-dimensional compounds of tetrahedral silane / siloxane units. The oligomeric siloxane can e.g. are formed from hydrolysis and condensation of one or more identical or different monomeric silanes.

An alkoxy-containing siloxane may be linear, cyclic or three-membered branched. It is preferably an oligomeric alkoxy-containing siloxane.

Such an oligomeric siloxane contains functional groups derived from the monomeric silanes used in their synthesis. For example, a first condensation of two tetramethoxysilane molecules results in a dimer containing six functional groups; Each of a functional group of each molecule is formed by condensation of the linkage. As already stated, the structure of the oligomers formed can be complicated. The number of functional groups in the oligomer can be determined by the degree of condensation, the type of condensation and monomers used Silanes vary, but is at least 2, but usually larger, for example 4 or more.

The degree of condensation of the oligomeric siloxane, i. the number of monomeric silanes condensed with each other can vary widely depending on

Application vary, but may e.g. ranging from 2 to 200, and preferably from 4 to 50. It is understandable that the

Condensation degree, especially at higher degrees of condensation, often only represents an average value.

The degree of condensation refers to the number of condensed monomeric alkoxysilanes in the siloxane and can also be referred to as the degree of polymerization. The mean degree of condensation of a

Alkoxylene-containing siloxane is at least 5, more preferably at least 6, and most preferably at least 7. The average degree of condensation of the alkoxylene-containing siloxane can vary widely depending on the application and may preferably be e.g. not more than 15, and more preferably not more than 12. It is understood that the degree of condensation, especially at higher condensation levels, often represents an average value, i. E. As a rule, the siloxane is a mixture of compounds of different degrees of condensation.

The average degree of condensation is understood here as the average degree of condensation based on the number average. As is known to those skilled in the art, this can be determined by measuring the siloxane using ²⁹ Si NMR spectroscopy and evaluating the spectrum obtained. The

Measurement and determination can be carried out as described in J. Zhang et al, J Sol-Gel Sei Technol, 2010, 56, 197-202. respectively.

Of course, as organoalkoxysilane or organoalkoxysiloxane crosslinker V for the silicone composition according to the invention also any mixture of the aforementioned silanes and / or siloxanes can be used. The composition of the invention further comprises 1 to 7

Parts by weight per 100 parts by weight of polydiorganosiloxane OH-PDMS of an organoalkoxysilane or organoalkoxysiloxane AS which contains at least one aminoalkyl group having a primary amino group.

The organoalkoxysilane or organoalkoxysiloxane AS are essentially the same structures as described above for the crosslinker V, in particular also for the oligomeric siloxanes, with the difference, however, that the organoalkoxysilane or organoalkoxysiloxane AS comprises at least one aminoalkyl group having a primary amino group. monomers

Organoalkoxysilanes AS can contain 1 or 2 aminoalkyl groups and 2 or 3 alkoxy groups per silicon atom. Oligomeric organoalkoxysiloxanes AS can also have more or fewer amino groups.

The addition of the organoalkoxysilane or organoalkoxysiloxane AS, on the one hand, causes the composition to cure more rapidly, since the amino group acts cocatalytically, on the other hand, it surprisingly leads to the compositions, if all other constituents according to the invention (with restrictions with respect to organoalkoxysilane or

Organoalkoxysiloxane OS) are included, become self-leveling.

Specific examples of monomeric organoalkoxysilanes AS are 3-aminopropyltrimethoxysilane and 2-aminoethyl-3-aminopropyltrimethoxysilane, as well as the corresponding compounds in which the methoxy group has been replaced by ethoxy or propoxy, for example 3-aminopropyltriethoxysilane.

Specific Examples of Suitable Oligomers Organoalkoxysiloxanes AS are those commercially available, e.g. under the trade names

Dynasylan ^® 1146 from Evonik Degussa GmbH or Hansa Care 8038 from the company CHT GmbH. Furthermore, the composition according to the invention comprises up to 5

Parts by weight per 100 parts by weight of polydiorganosiloxane OH-PDMS of an organoalkoxysilane or organoalkoxysiloxane OS which contains at least two alkoxysilane groups, with the proviso that the reactivity for the hydrolysis of the organoalkoxysilane or organoalkoxysiloxane OS is higher than the reactivity for the hydrolysis of the organoalkoxysilane or

Organoalkoxysiloxane crosslinker V.

The role of organoalkoxysilane or organoalkoxysiloxane OS is to be able to adjust the flow behavior of the composition according to the invention. Thus, the composition according to the invention can be formulated entirely without (or with low levels of) organoalkoxysilane or organoalkoxysiloxane OS, and is then present as a completely self-leveling, low-viscosity composition. By addition of organoalkoxysilane or

Organoalkoxysiloxane OS can then if desired a

Stability can be adjusted.

The effect depends on the amount of added

Organoalkoxysilane or organoalkoxysiloxane OS. The bigger the

added amount, the higher the thickening effect. For example, containing 0 to 1 parts by weight of a given

Organoalkoxysilans or organoalkoxysiloxane OS obtained a self-leveling composition, while having a content of 1 to 5

Parts by weight of the same Organoalkoxysilans or Organoalkoxysiloxans OS a steadily increasing with increasing proportion of organoalkoxysilane or Organoalkoxysiloxan OS composition is obtained. The expression of this thickening effect, or the amount of organoalkoxysilane or organoalkoxysiloxane OS required for a particular thickening effect of course depends on the nature of the organoalkoxysilane or

Organoalkoxysiloxans OS and the nature and amount of the other constituents of the composition, such as silica KS, from. It can therefore no general amount for all organoalkoxysilanes or

Organoalkoxysiloxanes OS in relation to an absolute

Thickening effect can be specified. On the other hand it is independent of the Type of Organoalkoxysilans or Organoalkoxysiloxans OS so that a larger amount thereof in the composition of a larger

Thickening effect shows.

Thus, with a carefully adjusted addition amount can

Organoalkoxysilane or organoalkoxysiloxane OS the desired

Flowability of a erfindungsgmässen composition can be set almost arbitrarily, without far-reaching reformulations of

Composition needed. Since the added amount moves in a small range and the remaining components such as silica KS and crosslinker V remain unchanged, the influence on the mechanical properties, such as Shore A hardness of the cured

Composition, minim. This is a significant advantage of the present invention.

The organoalkoxysilane or organoalkoxysiloxane OS are essentially the same structures as described above for the crosslinker V, in particular also for the oligomeric siloxanes.

However, it is important that the Reaktiviät (with respect to hydrolysis and / or

Condensation) of the alkoxy groups of the silane or siloxane OS is higher than the reactivity of the silane or siloxane crosslinker V. This can be achieved in several ways:

First, the crosslinker V may have alkoxy groups with a greater alkoxy group than the silane or siloxane OS. For example, methoxysilanes are more reactive than ethoxysilanes, which in turn are more reactive than e.g. Propoxysilanes are.

Accordingly, in a preferred embodiment, the

Organoalkoxysilane or organoalkoxysiloxane crosslinker V, and in particular also the organoalkoxysilane or organoalkoxysiloxane AS, ethoxy groups, while the organoalkoxysilane or organoalkoxysiloxane OS

Possesses methoxy groups. Another possibility is to use so-called "alpha" silanes or siloxanes (a-silanes or siloxanes) as organoalkoxysilane or organoalkoxysiloxane OS. These are silanes or siloxanes which have a functional group Si-CH 2 -X, where X is an organic radical which is bonded via an oxygen or nitrogen atom to the methylene group. By the heteroatom, which is bound via a methylene bridge on the silicon atom, electronic effects occur, which significantly increase the reactivity of alkoxy groups on this silicon atom. By using such "alpha" silanes or siloxanes OS, the effect according to the invention can also be achieved in compositions which use only methoxysilanes and siloxanes or only ethoxysilanes and siloxanes.

Accordingly, in a further preferred embodiment, all the alkoxysilanes and alkoxysiloxanes used are methoxysilanes and

Methoxysiloxanes, and the organoalkoxysilane or organoalkoxysiloxane OS has a functional group Si-CH 2 -X, wherein X is an organic radical which is bonded via an oxygen or nitrogen atom to the methylene group. X is particularly preferably a cyclohexylamino radical, an O-methylcarbamate radical or a methacryloxy radical, in particular a methacryloxy radical. These

Embodiment is particularly reactive and leads to particularly good mechanical properties.

Another preferred embodiment is according to

However, all alkoxysilanes and

Alkoxysiloxanes are ethoxysilanes and ethoxysiloxanes. This embodiment is particularly toxicologically harmless because no methanol is released.

A third possibility for achieving the difference in reactivity between crosslinker V and silane or siloxane OS is that silanes or siloxanes OS are higher-functional silanes and / or siloxanes, for example trialkoxysilanes, whereas for crosslinker V

lower functional silanes and / or siloxanes are used, for example dialkoxysilanes. Trialkoxysilanes are more reactive than the corresponding dialkoxysilanes.

Accordingly, in a further preferred embodiment, all the alkoxysilanes and alkoxysiloxanes used are methoxysilanes, and the

Organoalkoxysilane or organoalkoxysiloxane OS predominantly

Trimethoxysilane on, while the organoalkoxysilane or

Organoalkoxysiloxane crosslinker V predominantly methyldimethoxysilane has.

A fourth way to achieve the difference in reactivity between crosslinker V and silane or siloxane OS is that silanes or siloxanes OS silanes or siloxanes having at least one secondary

Amino group can be used in at least one organic radical. By the secondary amino group is a reactivity increase of

Alkoxysilane groups achieved. Examples of such silanes or siloxanes OS are bis (trimethoxysilylpropyl) amine, and N- (n-butyl) -3-aminopropyltrimethoxysilane, as well as their analogues with ethoxysilane groups instead of

Methoxysilane.

In a further preferred embodiment, the organoalkoxysilane or organoalkoxysiloxane OS accordingly has at least one

Aminoalkyl radical having a secondary amino group. These

However, embodiments of the organoalkoxysilane or organoalkoxysiloxane OS must not have any primary amino groups, since otherwise they would belong to the organoalkoxysilane or organoalkoxysiloxane AS.

All silanes and siloxanes used in the context of this invention are preferably free of oxime groups. Include oxime groups

Aldoximo groups and ketoximo groups. Such oxime groups are usually in the crosslinker of one-component according to the prior art

contain moisture-curing silicone formulations, if one

Acceleration of the cure by adding water is desired. As As explained above, in the presence of these oxime groups in the curing oximes are released, which have an unpleasant odor.

In the inventive composition are also 0.1 to 7

Parts by weight of at least one tin catalyst K included. These serve to catalyze the between the crosslinkable polydiorganosiloxane and the

Crosslinker (as well as other silane-functional constituents) in the presence of moisture or water occurring condensation or crosslinking and / or the previous hydrolysis, in the case of alkoxysilane.

The tin catalyst K is, in particular, an organotin compound.

Preferred organotin compounds are dialkyltin compounds, e.g. selected from dimethyltin di-2-ethylhexanoate, dimethyltin dilaurate, di-n-butyltin diacetate, di-n-butyltin di-2-ethylhexanoate, di-n-butyltin dicaprylate, di-n-butyltin di-2,2-dimethyloctanoate, di-n-butyltin dilaurate, Di-n-butyltin distearate, di-n-butyltin dimaleinate, di-n-butyltin dioleate, di-n-octyltin di-2-ethylhexanoate, di-n-octyltin di-2,2-dimethyloctanoate, di-n-octyltin dimaleinate, di- n-octyltin dilaurate, di-n-butyltin oxide and di-n-octyltin oxide.

It has been shown that other common metal catalysts, such as

For example, titanates are not or less well suited for the inventive composition. It has also been found that the presence of the organoalkoxysilane or organoalkoxysiloxane AS essential for the invention is indispensable for rapid curing.

If appropriate, the composition according to the invention may also contain further constituents, as are customary for one-component moisture-curing silicone formulations. Such additives are e.g. Plasticizers, inorganic and / or organic fillers, odorous substances,

Wetting aids, pigments, adhesion promoters, processing aids, rheology modifiers, stabilizers, dyes, inhibitors, heat stabilizers, stabilizers, antistatics, flame retardants, biocides, waxes, leveling agents, thixotropic agents and hydroxy-functional polyols.

Preferably, the silicone formulation optionally has one or more additional fillers. The fillers may e.g. affect both the rheological properties of the uncured formulation and the mechanical properties and surface finish of the cured formulation. It may be advantageous to use a mixture of different fillers.

Examples of suitable fillers are inorganic or organic fillers, such as natural, ground or precipitated calcium carbonates or chalks, which may be surface-treated, e.g. with fatty acids, surface-treated silicic acids, in particular pyrogenic silicic acids, aluminum hydroxides such as aluminum trihydroxide, carbon black, in particular

Industrial minerals, barium sulphate, dolomite, silica, kaolin, floss, quartz, calcined aluminas, aluminosilicates, magnesium aluminosilicates, zirconium silicates, cristobalite flour, diatomaceous earth, mica, titanium oxides, zirconium oxides, gypsum, graphite, carbon fibers, zeolites, or glass fibers, the surface of which may be combined with a Flydrophobierungsmittel is treated.

An example of optionally used polydimethylsiloxane plasticizers W-PDMS are trialkylsilyl-terminated polydimethylsiloxanes, the trialkylsilyl-terminated polydimethylsiloxanes preferably having a viscosity at 23 ° C. in the range from 1 to 10Ό00 mPa.s. It may also be e.g.

Trimethylsilylterminierte polydimethylsiloxanes are used in which some of the methyl groups are replaced by other organic groups such as phenyl, vinyl or trifluoropropyl. The

Polydimethylsiloxane plasticizer W-PDMS may also be monofunctional, i. one end is reactive, e.g. via a hydroxy end group. Certain

Hydrocarbons can also be used as plasticizers. The constituents of the composition according to the invention can be mixed with one another in a customary manner, for example with the aid of a suitable mixing unit such as, for example, a forced or planetary mixer. In preferred embodiments, the inventive

Composition additionally one or more of the following components: g) 5 to 40 parts by weight of reactive or non-reactive polydimethylsiloxane plasticizer W-PDMS, and / or

h) up to 150 parts by weight of further fillers, in particular chalk; and / or i) pigments, in particular carbon black, adhesion promoters, biocides, fragrances,

Desiccant and / or organic extenders.

The composition according to the invention is preferably free from

Oxime compounds.

Another object of the invention is the use of up to 5 parts by weight of an organoalkoxysilane or organoalkoxysiloxane OS, which contains at least two alkoxysilane, for adjusting the flow behavior of a one-component moisture-curing

Silicone composition comprising

a) 100 parts by weight of at least one crosslinkable

b) 5 to 20 parts by weight of at least one hydrophilic silica KS;

c) 1 to 10 parts by weight of at least one organoalkoxysilane or organoalkoxysiloxane crosslinker V which contains at least 2 alkoxysilane groups;

d) 1 to 7 parts by weight of an organoalkoxysilane or organoalkoxysiloxane AS, which contains at least one

Aminoalkyl group having a primary amino group; e) 0.1 to 7 parts by weight of at least one tin catalyst K; wherein the silicone composition contains less than 1.0 wt .-% water, based on the total composition, with the

Provision is made that the reactivity for the hydrolysis of the organoalkoxysilane or organoalkoxysiloxane OS is higher than the reactivity to

Hydrolysis of the Organoalkoxysilane or Organoalkoxysiloxane Crosslinker V.

The composition of the invention may be used as an adhesive, coating or sealant in a process for bonding or grouting

Substrates are used. The inventive method comprises a) the application of the composition to a substrate and

Contacting the mixture applied to the substrate with another substrate to obtain an adhesive bond between the substrates, or

introducing the composition into a joint between two substrates to obtain an inter-substrate disposal, and

b) curing the mixture,

wherein step b) preferably takes place by the action of atmospheric moisture.

The composition of the invention is placed in an airtight container, e.g. a cartridge, a bag or a hobbock and is thus stable in storage. To ensure a good storage stability, contains

Silicone composition according to the invention less than 1.0% by weight

Water, preferably less than 0.5 wt .-% water, more preferably less than 0.1 wt .-% water, based on the total composition. A low water content can be achieved in particular by the

Components according to the invention, in particular the hydrophilic silica KS, are dried in advance. These have heat and / or

Vacuum treatments proved to be suitable. These are known to the person skilled in the art of silicone formulation. For application, the container is opened and immediately afterwards

Composition by hand, e.g. a gun, or by automatic application device on the substrate or in the glue joint up or

brought in.

The application to a substrate or the introduction into a joint between substrates according to step a) of the abovementioned process can be carried out in a customary manner, e.g. by hand or in an automated process using robots. When adhered, the substrate provided with the mixture is contacted with another substrate, optionally under pressure, to obtain an adhesive bond between the substrates. Thereafter, in step b), the mixture is allowed to cure, usually at room temperature, to achieve the bonding or disposition of the substrates. In this way, the inventive bonded or grouted substrates are obtained with the cured composition as an adhesive or sealing material.

The substrates to be bonded, coated, pouring or grouting may be made of the same material or of a different material. All customary materials can be bonded, coated, cast or grouted with the one-component composition according to the invention. Preferred materials for bonding, coating,

Potting or grouting are glass, metals, e.g. Aluminum, copper,

Steel or stainless steel, concrete, mortar, building blocks, e.g. Sandstone and

Lime sandstone, asphalt, bitumen, plastics, e.g. Polyolefins, PVC, polyvinyl fluoride, PET, polyamide, polycarbonate, polystyrene or polyacrylate, and composites such as CFRP.

The inventive one-component composition can thus be used as an adhesive, coating, potting compound or sealant, for example in the fields of construction, plumbing, automotive, solar technology, wind power, white goods, facade and window construction, electronics and boat and shipbuilding. Examples

In the following, concrete embodiments of the invention are carried out, which are not intended to limit the scope of the invention.

The chemicals used can be found in the following Table 1.

Table 1: Chemicals used. Unless otherwise stated, data are by weight.

The proportions (parts by weight) of the constituents for the example compositions given in Tables 2 to 4 below were weighed out and applied to a Speedchixer from Hauschild at 23 ° C. and 50% R.F. for 20 seconds at 2000 rpm while applying a vacuum. The resulting mixtures were stored hermetically sealed at 23 ° C.

Tables 2 to 4 also contain the overviews of

Measurement results. All tests were carried out at 23 ° C and 50% r.F. (relative humidity).

The Shore A hardness was determined after curing the samples for 7 days at 23 ° C and 50% r.F. on a Shore A tester from Bareiss according to DIN ISO 7619-1. To determine the Shore A hardness, round specimens with a diameter of 42 mm and a thickness of 6 mm were produced.

The viscosity was determined in accordance with DIN EN ISO 3219 using a cone-and-plate viscometer MCR101 from Anton Paar, Austria, with cone type CP 25-1 and a distance of 0.049 mm at 23 ° C. The stated viscosity values refer to a shear rate of 0.1 s ¹ .

The determination of the flow behavior at rest was carried out by

Application of the compositions to a vertically mounted cardboard substrate from a 300 ml PE cartridge with hand gun at 23 ° C / 50% RH. In each case about 20 ml were applied on a base area of about 3 cm ² .

After 24 hours, the length of the run-off track (in mm) was measured.

hardened.

Claims

claims

1 . One-component moisture-curing silicone composition

full

a) 100 parts by weight of at least one crosslinkable

b) 5 to 20 parts by weight of at least one hydrophilic silica KS;

Aminoalkyl group having a primary amino group; e) 0.1 to 7 parts by weight of at least one tin catalyst K; f) up to 5 parts by weight of an organoalkoxysilane or organoalkoxysiloxane OS which is at least two

Alkoxysilane groups;

wherein the silicone composition contains less than 1.0 wt .-% water, based on the total composition, with the

Hydrolysis of the Organoalkoxysilane or Organoalkoxysiloxane Crosslinker V.

2. One-component moisture-curing silicone composition according to claim 1, characterized in that the polydiorganosiloxane OH-PDMS is a linear polydiorganoxiloxane according to formula (I), wherein the radicals R ¹ , R ² and R ^{3 are} independently linear or branched, monovalent hydrocarbon radicals having 1 to 12 carbon atoms, which optionally one or more heteroatoms, and optionally one or more CC multiple bonds and / or optionally cycloaliphatic and or have aromatic portions;

R ^{4 is} a hydroxyl group;

the index p is a value of 0, 1 or 2; and

the index m is selected so that the polydiorganosiloxane OH-PDMS at a temperature of 23 ° C has a viscosity of 1 Ό00 to 350Ό00 mPa · s, measured according to DIN EN ISO 3219.

3. One-component moisture-curing silicone composition according to claim 2, characterized in that the radicals R ¹ , R ² and R ^{3 are} methyl groups.

4. One-component moisture-curing silicone composition according to one of claims 1 to 3, characterized in that the

Polydiorganosiloxane OH-PDMS at a temperature of 23 ° C a

Viscosity of 5Ό00 to 120Ό00 mPa-s, preferably from 10Ό00 to 80Ό00 mPa-s, measured according to DIN EN ISO 3219, having.

5. One-component moisture-curing silicone composition according to any one of claims 1 to 4, characterized in that the organoalkoxysilane or organoalkoxysiloxane crosslinker V at least one non-hydrolyzable functional group selected from methyl, Ethyl, vinyl, n-propyl, cyclopentyl, phenyl, cyclohexyl, n-octyl, isooctyl and hexadecyl.

6. One-component moisture-curing silicone composition according to one of claims 1 to 5, characterized in that the

Organoalkoxysilane or organoalkoxysiloxane OS at least one aminoalkyl radical having a secondary amino group.

7. One-component moisture-curing silicone composition according to one of claims 1 to 6, characterized in that the

Organoalkoxysilane or organoalkoxysiloxane OS has a functional group Si-CH 2 -X, wherein X is an organic radical which is bonded via an oxygen or nitrogen atom to the methylene group.

8. One-component moisture-curing silicone composition according to

Claim 7, characterized in that X is a Cyclohexylaminorest, an O-methylcarbamate or a Methacryloxyrest.

9. One-component moisture-curing silicone composition according to any one of claims 1 to 8, characterized in that the hydrophilic silica KS is a fumed silica.

10. One-component moisture-curing silicone composition according to any one of claims 1 to 9, characterized in that in the composition additionally

g) 5 to 40 parts by weight of reactive or unreactive

Polydimethylsiloxane plasticizer W-PDMS, and / or h) up to 150 parts by weight of further fillers, in particular chalk; and or

i) pigments, in particular carbon black, adhesion promoters, biocides,

Fragrances, drying agents and / or organic extenders; are included.

1 1. One-component moisture-curing silicone composition according to any one of claims 1 to 9, characterized in that the

Composition is free of oxime compounds.

12. A method for bonding or grouting substrates with a

one-component composition according to any one of claims 1 to 11, comprising

a) the application of the composition to a substrate and

Contacting the mixture applied to the substrate with another substrate to provide an adhesive bond between the substrates

To obtain substrates, or

b) the flashing of the mixture,

wherein step b) preferably takes place by the action of atmospheric moisture.

13. Bonded or jointed substrates obtainable by a process according to claim 12.

14. Use of up to 5 parts by weight of an organoalkoxysilane or organoalkoxysiloxane OS which has at least two

Alkoxysilane containing for adjusting the flow behavior of a one-component moisture-curing silicone composition comprising

a) 100 parts by weight of at least one crosslinkable

b) 5 to 20 parts by weight of at least one hydrophilic silica KS; c) 1 to 10 parts by weight of at least one organoalkoxysilane or organoalkoxysiloxane crosslinker V which contains at least 2 alkoxysilane groups;

Provision is made that the reactivity for the flyrolysis of the organoalkoxysilane or organoalkoxysiloxane OS is higher than the reactivity for the flydrolysis of the organoalkoxysilane or organoalkoxysiloxane crosslinker V.

15. Use of a one-component composition according to

any one of claims 1 to 1 1 as an adhesive, coating, potting compound or sealant, especially in the fields of construction, plumbing, automotive, solar technology, wind power engineering, white goods, facade and window construction, electronics and boat and shipbuilding.