EP1926739A1

EP1926739A1 - Surfactant-stabilized organoalkoxysilane composition

Info

Publication number: EP1926739A1
Application number: EP06806742A
Authority: EP
Inventors: Jolanda Sutter; Wolf-Rüdiger Huck
Original assignee: Sika Technology AG
Current assignee: Sika Technology AG
Priority date: 2005-09-02
Filing date: 2006-09-01
Publication date: 2008-06-04
Also published as: AU2006286513A1; EP1760084A1; RU2387660C2; RU2008112665A; KR20080042920A; CA2621020A1; JP5254791B2; JP2009507100A; US8377191B2; WO2007026015A1; BRPI0616124A2; CN101305013A; US20090053411A1; ZA200801622B

Abstract

The present invention relates to organoalkoxysilane compositions which comprise at least one organoalkoxysilane S, and at least one anhydrous surfactant T, where the weight fraction of all of the organoalkoxysilanes S is 33% by weight, based on the weight of the organoalkoxysilane composition, and where the ratio of the weight sum of all of the organoalkoxysilanes S to the weight sum of all of the anhydrous surfactants T (S:T) has a value of from 5:1 to 1:2.

Description

TENSID-STABILIZED ORGANOALKOXYSILANE COMPOSITION

Technical area

The invention relates to the field of organoalkoxysilanes.

State of the art

Organoalkoxysilane are known substances and have long been used for example as adhesion promoters. They are often referred to by the skilled person as silanes. They have alkoxysilane groups which hydrolyze in contact with water in liquid form or as atmospheric moisture to form a silanol group (Si-OH) and then can crosslink to siloxane compounds. This can lead to precipitations or cloudiness appearing after a very short time. This sensitivity is particularly pronounced in polar organoalkoxysilanes, as well as at basic pH, and therefore particularly aminosilanes.

Therefore, when handling organoalkoxysilanes care must be taken that they are stored and processed in the absence of moisture. This often leads to difficulties in practice, for example, when a package is not tight or was opened and badly closed.

Presentation of the invention

The object of the present invention is therefore to improve the storage stability of organoalkoxysilanes and in particular to improve the sensitivity of the organoalkoxysilanes to water, in particular to atmospheric moisture. Surprisingly, it was found that the

Organoalkoxysilane according to claim 1 can achieve this object.

Ways to carry out the invention

The present invention relates to organoalkoxysilane compositions containing at least one organoalkoxysilane S and at least one anhydrous surfactant T, wherein the weight fraction of all organoalkoxysilanes S ≥ 33 wt .-%, based on the weight of the Organoalkoxysilanzusam- composition and wherein the ratio the sum by weight of all organoalkoxysilanes S for the sum by weight of all anhydrous surfactants T (ST) has a value of 5: 1 to 1: 2.

The term "organoalkoxysilane" or "silane" for short in this document refers to compounds in which at least one, usually two or three alkoxy groups are bonded directly to the silicon atom (via a Si-O bond), and the on the other hand at least one directly to the silicon atom (via an Si-C bond) bonded organic radical and have no Si-O-Si bonds. Accordingly, the term "silane group" denotes the silicon-containing group bonded to the organic radical of the organoalkoxysilane The organoalkoxysilanes, or their silane groups, have the property of hydrolyzing on contact with moisture, forming organosilanols, ie organosilicon compounds containing one or more silanol groups (Si-OH groups) and, by means of subsequent condensation reactions, organosiloxanes, that is to say organosiloxanes containing one or more siloxane groups (Si-O-Si-groups) With terms such as "aminosilane", "epoxysilane "," Alkylsilane "and

"Mercaptosilane" refers to silanes which have the corresponding functional group, in this case an aminoalkylalkoxysilane, epoxyalkylalkoxysilane, alkylalkoxysilane and mercaptoalkylalkoxysilane. The term "anhydrous" in this document is not to be construed as "absolutely free of water". There are therefore also compounds and

Compositions referred to as "anhydrous" which contain minor traces of

Contain water, i. which contain a residual water content of at most 1% by weight, in particular of at most 0.5% by weight.

Organoalkoxysilanes S are, in particular, aminosilanes, epoxysilanes, mercaptosilanes and alkylsilanes.

Aminosilanes are, in particular, aminosilanes of the formula (I) or

Reaction products of the formula (I) which has at least one secondary or primary amino group, with a compound (ARV) which contains at least one functional group which can react with a primary or secondary amino group.

Here, R ^{1 is} an alkyl group having 1 to 8 C atoms, preferably a methyl or an ethyl group. R ¹ is preferably a methyl group.

Furthermore, R ^{2 is} an alkyl group having 1 to 5 C atoms, preferably a methyl group or an ethyl group or an isopropyl group. R ² is preferably a methyl group or an ethyl group.

Furthermore, R ^{3 is} a linear or branched alkylene group having 1 to 4 carbon atoms. R ³ is preferably a propylene group. Furthermore, R ^{4 is} H or a linear or branched alkyl group having 1 to 10 C atoms or a substituent of the formula (II)

Furthermore, R is H or a linear or branched alkyl group having 1 to 10 C atoms or a linear or branched alkyl group having 1 to 10 C atoms with further hetero atoms or for a substituent of the formula (II)

A particularly advantageous radical of a linear alkyl group having 1 to 10 C atoms with further heteroatoms R ⁵ is the radical CH ₂ CH ₂ NH ₂ . Finally, the subscript a stands for a value 0, 1 or 2, in particular for 0 or 1. Preferably a stands for 0.

Examples of such aminosilanes of the formula (I) are 3-aminopropyltrimethoxysilane, 3-aminopropyldimethoxymethylsilane, 3-amino-2-methylpropyltrimethoxysilane, 4-aminobutyltrimethoxysilane, 4-aminobutyldimethoxymethylsilane, 4-aminobutyldimethoxymethylsilane, 3-methylbutyltrimethoxysilane, 4-amino-3,3-dimethylbutyltrimethoxysilane, 4-amino-3,3-dimethylbutyldimethoxymethylsilane, 2-aminoethylthymethoxysilane, 2-aminoethyldimethoxymethylsilane, aminomethyltrimethoxysilane, Aminomethyldimethoxymethylsilane, aminomethylmethoxymethylsilane, N-methyl-3-aminopropyltrimethoxysilane, N-ethyl-3-aminopropyltrimethoxysilane, N-butyl-3-aminopropyltrimethoxysilane, N-cyclohexyl-3-aminopropyltrimethoxysilane, N- Phenyl-3-aminopropyltrimethoxysilane, N-methyl-3-amino-2-methylpropyl-trimethoxysilane, N-ethyl-3-amino-2-methyl-propyl-trimethoxysilane, N-ethyl-3-aminopropyl-dimethoxymethylsilane, N-phenyl-4-aminobutyl-trimethoxysilane, N-phenyl-aminomethyl-dimethoxymethyl-silane, N-cyclohexyl-aminomethyl-dimethoxyme ethyl silane, N-methyl-amino-methyl-dimethoxymethylsilane, N-ethyl-aminomethyl-dimethoxymethylsilane, N-propylaminomethyl-dimethoxymethylsilane, N-butyl-aminomethyl-dimethoxymethylsilane; N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, bis (trimethoxysilylpropyl) amine, tris (trimethoxysilylpropyl) amine and their analogues with ethoxy or isopropoxy groups instead of the methoxy groups on the silicon.

Preferred aminosilanes of the formula (I) are aminosilanes which are selected from the group comprising aminosilanes of the formula (III), (IV) and (V).

The most preferred aminosilanes of the formula (I) are the aminosilanes 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, 3- [2- (2-aminoethylamino) ethylamino] -propyl- trimethoxysilane, bis (trimethoxysilylpropyl) amine and tris (trimethoxysilylpropyl) amine.

In one embodiment, the aminosilane is a reaction product of an aminosilane of formula (I), as described above, having at least one secondary or primary amino group, with a compound (ARV) having at least one functional group which is substituted with a primary or secondary amino group can react.

This functional group, which can react with a primary or secondary amino group, is preferably an epoxy group. But there are also other groups, such as isocyanate groups or activated double bonds, conceivable. Particularly suitable compounds with epoxy groups are epoxysilanes. Preferred compounds (ARV) which can react with the aminosilane of the formula (I) with at least one secondary or primary amino group are epoxysilanes of the formula (VI)

R ¹ here stands for an alkyl group having 1 to 8 C atoms, preferably a methyl or an ethyl group. stands. R ² is an alkyl group having 1 to 5 carbon atoms. Furthermore, R ^{3 is} a linear or branched Alkylene group having 1 to 4 carbon atoms and a 'for 0, 1 or 2, in particular for 0 or 1.

R ¹ is in particular a methyl group. R ² is preferably a methyl group or an ethyl group or an isopropyl group. As particularly preferred, R ^{2 is} a methyl group or an ethyl group. R ³ is preferably propylene. The index a 'preferably stands for 0.

Examples of epoxysilanes are 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 3-glycidyloxypropyltriethoxysilane and 3-glycidyloxypropyltrimethoxysilane. Preferred epoxysilanes are 3-glycidyloxypropyltriethoxysilane and 3-glycidyloxypropyltrimethoxysilane. The most preferred epoxy silane is 3-glycidyloxypropyltrimethoxysilane.

The aminosilane of the formula (I) which is used for the reaction product are, in addition to N- (2-aminoethyl) -3-aminopropyltrimethoxysilane and N- (2-aminoethyl) -3-aminopropyltriethoxysilane, preferably N- (2 Aminopropyl) -3-aminopropyltrimethoxysilane, in particular aminosilanes of the formula (III) or (IV), in particular 3-aminopropyltrimethoxysilane, bis (trimethoxysilylpropyl) amine, 3-aminopropyltriethoxysilane and bis (triethoxysilylpropyl) amine. Preference is given to 3-aminopropyltrimethoxysilane and bis (thmethoxysilylpropyl) amine.

Depending on the stoichiometry of the aminosilane of formula (I) and the amine-reactive compound (ARV), the reaction product may or may not have primary or secondary amino groups.

Examples of such reaction products are compounds of the formula (VII), (VIII), (IX), (X), (XI) and (XII).

The compounds of formulas (VII), (VIII) and (IX) are obtained from the reaction of N- (2-aminoethyl) -3-aminopropyltrimethoxysilane and 3-glycidyloxypropyltrimethoxysilane. The compounds of formulas (X) and (XI) are obtained from the reaction of 3-aminopropyltrimethoxysilane and 3-glycidyloxypropyltrimethoxysilane.

\

The compound of formulas (XII) is obtained from the reaction of bis (tri-methoxysilylpropyl) amine and 3-glycidyloxypropyltrimethoxysilane.

Examples of amine-reactive compounds (ARV) with activated double bonds are, for example, α, β-unsaturated compounds, in particular maleic diesters, fumaric diesters, citraconic diesters, acrylic esters, methacrylic acid esters, cinnamic acid esters, itaconic diesters, vinylphosphonic diesters, vinylsulfonyl esters, vinylsulfones,

Vinylnitriles, 1-nitroethylene or Knoevenagel condensation products such as those of malonic diesters and aldehydes such as formaldehyde, acetaldehyde or benzaldehyde. Such amine-reactive compounds form Michael adducts in which the amine adds to the double bond. Examples of such reaction products are Michael adducts of 3-aminopropyltrimethoxysilane, 3-aminopropyldimethoxymethylsilane, 4-amino-3,3-dimethylbutyltrimethoxysilane, 4-amino-3,3-dimethylbutyldimethoxymethylsilane, aminomethyl- trimethoxysilane or aminomethyldimethoxymethylsilane with dimethyl, diethyl or dibutyl maleate, acrylate tetrahydrofurfuryl, isobornyl, hexyl, lauryl, stearyl, 2-hydroxyethyl or 3-hydroxypropyl ester, phosphonic acid dimethyl, diethyl or dibutyl ester, acrylonitrile, 2-pentenenitrile, fumaronitrile or β-nitrostyrene, as well as the analogues of said aminosilanes with ethoxy instead of the methoxy groups on the silicon. Insbeondere the Michael adduct N- (3-trimethoxysilyl-propyl) - amino-succinic acid diethyl ester is mentioned.

Examples of amine-reactive compounds (ARV) with isocyanate groups are isocyanatosilanes or polyisocyanates. Particular examples of isocyanatosilane are 3-isocyanatopropyltrimethoxysilane and 3-isocyanatopropyltriethoxysilane. As polyisocyanates, for example, 2,4- and 2,6-toluene diisocyanate (TDI) and any mixtures of these isomers, 4,4'-, 2,4'- and 2,2'-diphenylmethane diisocyanate (MDI) and any mixtures of these and others Isomers, 1, 3 and 1, 4-phenylene diisocyanate, 2,3,5,6-tetramethyl-1,4-diisocyanatobenzene, 1,6-hexamethylene diisocyanate (HDI), 2-methylpentamethylene-1,5-diisocyanate, 2,2,4- and 2,4,4-trimethyl-1,6-hexamethylene diisocyanate (TMDI), 1, 12-dodecamethylene diisocyanate, cyclohexane-1, 3- and - 1, 4-diisocyanate and any mixtures of these isomers , 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (= isophorone diisocyanate or IPDI), Perhydro-2,4'- and -4,4'-diphenylmethane diisocyanate (HMDI), 1,4-diisocyanato-2,2,6-trimethylcyclohexane (TMCDI), m- and p-xylylene diisocyanate (XDI), 1, 3 and 1, 4-tetramethylxylylene diisocyanate (TMXDI), 1, 3- and 1, 4-bis (isocyanatomethyl) cyclohexane, oligomers of the aforementioned polyisocyanates, as well as any mixtures of the aforementioned polyisocyanates. Preferred are MDI, TDI, HDI and IPDI, and their biurets or isocyanurates.

If the organoalkoxysilane S is an epoxysilane, the epoxysilanes as described above as amine reactive compounds (ARV) are to be preferred.

Examples of mercaptosilane as organoalkoxysilane S are 3-mercaptopropyltrimethoxysilane and 3-mercaptopropyltriethoxysilane.

If the organoalkoxysilane S is an alkylsilane, in particular the silanes with C _θ alkyl may be mentioned such as methyltri- trimethoxysilane, ethyltrimethoxysilane and butyl trimethoxysilane.

Aminosilanes are compared to epoxysilanes, mercaptosilanes and

Alkyl silanes as Organoalkoxysilan S preferred.

The organoalkoxysilanes S have in particular no chemical groups which can react with the surfactant T.

As surfactants T, natural or synthetic substances can be used, which in solutions reduce the surface tension of the water or other liquids. Surfactants, also called wetting agents, anionic, cationic, nonionic or ampholytic surfactants or mixtures thereof can be used.

Examples of anionic surfactants are surfactants having carboxylate, sulfate, phosphate or sulfonate groups, such as, for example, amino acid derivatives, fatty alcohol ether sulfates, fatty alcohol sulfates, soaps, Alkylphenol ethoxylates, fatty alcohol ethoxylates, but also alkanesulfonates,

Olefinsulfonates or alkyl phosphates.

Examples of nonionic surfactants, the so-called nonionic surfactants, include ethoxylates, such as ethoxylated addition products of alcohols, for example polyoxyalkylene polyols,

Amines, fatty acids, fatty acid amides, alkylphenols, ethanolamides, fatty amines,

Polysiloxanes or fatty acid esters, but also alkyl or alkylphenyl polyglycol ethers, such as fatty alcohol polyglycol ethers, or

Fatty acid amides, alkyl glycosides, sugar esters, sorbitan esters, polysorbates or trialkylamine oxides, but also esters and amides of poly (meth) acrylic acids with

Polyalkylene glycols or Aminopolyalkylenglykole, the one-sided with at best

Alkly groups can be completed.

Examples of cationic surfactants are quaternary ammonium or

Phosphonium compounds, such as, for example, tetraalkylammonium salts, N-, N-dialkylimidazoline compounds, dimethyldistearylammonium compounds, or N-alkylpyridine compounds, in particular ammonium chlorides.

The ampholytic or amphoteric surfactants include amphoteric electrolytes, so-called ampholytes, such as

Aminocarboxylic acids, and betaines. Such surfactants are widely available commercially.

Particularly suitable are nonionic surfactants, especially alkoxylated alcohols. Alkoxylated nonionic fluorinated surfactants, in particular Zonyl® FSO-100, which have been shown to be particularly suitable, have been found to be suitable

ABCR, Germany, alkoxylated alcohols or alkoxylated alkylphenols, in particular Antarox FM 33, which is commercially available commercially from Rhodia.

The surfactant must be anhydrous, as the introduction of significant amounts of water by the surfactant can lead to premature hydrolysis of the silanes and thus storage problems. To understand the term "anhydrous", reference is made to the above definition.

Furthermore, the ratio of organoalkoxysilane S to surfactant T in a certain ratio is observed. If the ratio S: T is greater than 5: 1, the sensitivity to water is not significantly improved. If this ratio is less than 1: 2, in particular less than 2: 3, the adhesion is increasingly adversely affected if the silane composition is used as an adhesion promoter. The optimum ratio of organoalkoxysilane S to surfactant T is, in particular for aminosilanes as organoalkoxysilane S, a value of 3: 1 to 2: 3.

The organoalkoxysilane composition may contain other ingredients. Examples of such additives are solvents, inorganic fillers, catalysts and stabilizers, dyes or pigments.

If such further constituents are used, care must be taken on the one hand that the composition has not more than 1% by weight, in particular not more than 0.5% by weight, of water. On the other hand, the organoalkoxysilane composition is required to have not less than 33% by weight, more preferably not less than 40% by weight of organoalkoxysilane S.

Preferably, the Organoalkoxysilanzusammensetzungen which are in

Substantially consist only of organoalkoxysilane S and surfactant T. Under

"Substantially" is understood here that the total weight of organoalkoxysilane S and surfactant T more than 90 wt .-%, in particular more than 95%, preferably more than 99 wt .-%, based on the weight of

Organoalkoxysilane composition.

Since, in particular, polar, in particular water-soluble, organoalkoxysilanes are more sensitive to storage stability with respect to water, the improvements achievable by the present invention are particularly evident in the case of polar, especially water-soluble, organoalkoxysilanes S. this is the

Reason why very apolar organoalkoxysilanes S, such as higher

Alkylalkoxysilanes, such as dodecyltrimethoxysilane or octadecyltrimethoxysilane, are not preferred as organoalkoxysilanes S. The improvement of

Storage stability to water is particularly evident in aminosilanes as

Organoalkoxysilanes S. The Organoalkoxysilanzusammensetzungen, especially if they contain aminosilanes as Organoalkoxysilane S, are significantly less sensitive to the influence of water during storage. This is particularly evident when water, especially in the form of atmospheric moisture, can come into contact with the Organoalkoxysilanzusammensetzungen. Reasons for such a contact, for example, be leaky packaging. So it may well happen in practice that, for example, original packaging is not tight, or that a storage container after opening the first time bad or leaking is closed again or that it is exposed to the environment completely unsealed for a certain time. Finally, the storage stability of the Organo alkoxysilanzusammensetzungen is greatly increased compared to the prior art, if they are stored in plastic vessels. This is especially the case when the ratio of surface to volume of the container is large, ie for small-volume containers. The plastics commonly used for plastic containers, such as polyethylene or polypropylene, in many cases have an insufficient water vapor diffusion tightness. Silane compositions according to the prior art are therefore stored for small volumes not in plastic containers but in glass or metal containers. The possibility of using plastic containers for the storage of the organoalkoxysilane compositions according to the invention therefore gives rise to enormous cost and weight advantages as well as additional freedom in the design and the design of the package. The improved shelf life, or lower

Sensitivity to water during storage is particularly evident in the absence or at least significant delay in the formation of precipitates or cloudiness.

The organoalkoxysilane compositions are described in particular as

Adhesive used. These adhesion promoters may be part of compositions which must have good adhesion. Thus, organoalkoxysilane compositions as a component of adhesive or Sealants possible. Likewise, they can be used in coatings such as paints or floor coverings. In one embodiment, the organoalkoxysilanes S can react covalently with reactive groups. Thus, for example, aminosilanes of the formula (I) can be used to react with isocyanate group-containing prepolymers and to produce so-called silane-terminated polyurethanes (SPUR).

Furthermore, the Organoalkoxysilanzusammensetzungen can be used as a pretreatment agent or part of a pretreatment agent to improve the adhesion of an applied adhesive or sealant. Such pretreatment agents are also often called

Called primer. Such a primer can be one or two-component.

Here, an organoalkoxysilane compositions or a

Composition containing the Organoalkoxysilanzusammensetzungen applied to a substrate to be bonded or sealed or coated. After the so-called flash-off time has elapsed, then an adhesive, a sealant or a coating is applied. These are in particular reactive, i. crosslinking adhesives, sealants or coatings, in particular based on isocyanate group-containing polyurethanes.

In particular, aqueous two-component primers consisting of a component K1 and a component K2 are preferred as two-component primers. In one embodiment of the invention, the first component K1 contains an organoalkoxysilane composition and the second component K2 contains water and an acid. It is preferred that after the mixing of component K1 and K2 a pH of 2-5, in particular 3.5-4.5, results. Such a primer composition can be mixed well by simple shaking and hydrolyzed rapidly while slowing the condensation and thus the formation of undesirable siloxanes. As a result, a very good adhesion is built up, without forming unwanted precipitation or turbidity between the mixing and the application of the aqueous primer. Examples

Tabellei Organoalkoxysilane used.

Further, the reaction product RP1 was prepared from 3-glycidyloxypropyl-trimethoxysilane and N- (2-aminoethyl) -3-aminopropyltrimethoxysilane by mixing 1 mole of A1120 with 3 moles of A187. Immediately after mixing, the conversion could be checked with IR. The characteristic of the epoxy group band at about 910 cm ^"1 is still detectable immediately after mixing, but disappears quickly.

Table 2 Surfactants used.

In Table 3, the ratio of organoalkoxysilane to surfactant was varied. As organoalkoxysilane, the reaction product RP1 was used and combined with different surfactants.

In the first reference series Ref.SI no surfactant, ie pure organoalkoxysilane was used. In the second, resp. third reference series Ref.S2 resp. Ref.S3 was the ratio 20: 1 resp. 10: 1st The respective surfactant was to 2.5 g of the reaction product RP1 in glass vessel (diameter 12 mm, 4 cm high, volume about 4.5 ml, with plastic screw cap), which previously dried in an oven at 200 ⁰ C for one day and at 25 ° C / 50% rel. Humidity was cooled to room temperature, added. Subsequently, the vessels filled in this way were closed with a lid and stored in a furnace (Ehret, TK / L 4061) with circulating air at 50 ^° C. During 30 days, the samples were visually assessed daily. Table 3 shows the stability by specifying the number of days it took for the sample to gel. If, after the 30th day, the sample was still flawless, the value> 30 was given.

Stability (number of days until gelled) of organoalkoxysilane-surfactant mixtures at 50 ^° C. in a closed vessel.

In Table 4, various silanes and different surfactants were blended in a mixing ratio S: T of 2,125: 1, corresponding to a content of the organoalkoxysilane S of 68% by weight of the total weight of the entire composition, as previously described. In this

However, a 1 mm hole was drilled in the lid by means of a drill to simulate leaking packaging. The storage and determination of the stability is carried out as for the experiments in Table 3. The

Comparative experiment series Ref.S4 was carried out without the addition of surfactants, ie as pure organoalkoxysilanes.

Table 4. Stability (number of days until gelled) of organoalkoxysilane surfactant mixtures at 50 ^° C. in a vessel with a hole in the lid.

In a further series of experiments, the storage stabilities of reaction products of aminosilanes and epoxysilane-containing compositions with different surfactants were compared.

In this case, the reaction product RP1 already described was used. Furthermore, a reaction product RP2 was prepared from 3-glycidyloxypropyltrimethoxysilane and 3- [2- (2-aminoethylamino) ethylamino] propyltrimethoxysilane by mixing 1 mol of A1130 with 6.6 mol of A187.

In Table 5, RP1 and RP2 were mixed with different surfactants in a mixing ratio ST of 2,125: 1, corresponding to a content of the organoalkoxysilane S of 68% by weight of the total weight of the entire composition, as previously described. In this series of experiments, the vessel with a closed lid (without a hole as for Table 4) at 50 ⁰ C, as already described in the oven, or at 23 ° C / 50% rel. Humidity stored. Stability is determined as for the experiments in Table 3. The comparative test series Ref.S5 was carried out without the addition of surfactants, ie as pure organoalkoxysilanes.

Table 5. Stability (number of days until gel) of organoalkoxysilane-surfactant blends at 50 ⁰ C and 23 ° C in a sealed vessel.

Preparation of Aqueous Primers

Organoalkoxysilane compositions of A1110 and various surfactants were prepared in the proportions shown in Table 6 and used as a first component K1 of an aqueous primer. The second component K2 consisted of water and 1 wt .-% acetic acid. 1.05 g of component K1 was added to 49 g of component K2 and shaken.

This mixture was then applied to the ceramic edge of a VSG front panel of a Mitsubishi Space Wagon by Splintex using a cellulose cloth (Tela®, Tela-Kimberly Switzerland GmbH) soaked in it. After a drying time of 10 minutes, the one-component moisture-curing polyurethane adhesive Sikaflex®-250 DM-2 or Sikaflex®-250 HMV-2 +, which both contain polyurethane prepolymers with isocyanate groups and are commercially available from Sika Schweiz AG, was applied as a round bead with a cartridge press and a die and during 4 days at 23 ° C and 50% rel. Humidity cured. Adhesion test ("track test")

The adhesion of the adhesive was tested by means of a 'bead test'. This is cut at the end just above the adhesive surface. The cut end of the caterpillar is held with a round tongs and pulled from the ground. This is done by carefully rolling up the bead on the pliers tip, as well as placing a cut perpendicular to the track pulling direction down to the bare ground. The caterpillar pull-off speed should be selected so that a cut must be made approx. Every 3 seconds. The test track must be at least 8 cm. The adhesive that remains after the removal of the caterpillar from the substrate (cohesive failure) is assessed. The assessment of the adhesive properties is carried out by estimating the cohesive part of the adhesive surface:

1 => 95% cohesive failure

2 = 75 - 95% cohesive failure

3 = 25 - 75% cohesive failure

4 = <25% cohesive failure

5 = 0% cohesive failure (purely adhesive failure) Test results with a rating of 4 or 5 are considered insufficient.

The liability results are given in Tables 6 and 7.

Table 6. Aqueous primers with silane / surfactant mixture in component K1. Adhesion of Sikaflex® 250 DM-2

Table 7. Aqueous primers with silane / surfactant mixture in component K1. Liability of Sikaflex® 250 HMV-2 +

Claims

claims

An organoalkoxysilane composition comprising at least one organoalkoxysilane S and at least one anhydrous surfactant T; wherein the weight fraction of the sum of all organoalkoxysilane S> 33

% By weight, based on the weight of the Organoalkoxysilanzusammen- set tion and wherein the ratio of the sum by weight of all organoalkoxysilanes S to the sum by weight of all anhydrous surfactant T (S: T) has a value of 5: 1 to 1: 2.

2. Organoalkoxysilane composition according to claim 1, characterized in that the surfactant T is a nonionic surfactant.

3. Organoalkoxysilane according to claim 1 or 2, characterized in that the weight ratio of organoalkoxysilane S to anhydrous surfactant T (ST) has a value of 3: 1 to 2: 3.

4. Organoalkoxysilane composition according to one of the preceding claims, characterized in that the weight fraction of the sum of all organoalkoxysilane S> 40 wt .-%, based on the weight of the Organoalkoxysilanzusammensetzung.

5. Organoalkoxysilane composition according to one of the preceding claims, characterized in that the organoalkoxysilane S is an aminosilane.

6. Organoalkoxysilane composition according to one of the preceding claims, characterized in that the aminosilane has the formula (I)

wherein R ^{1 is} an alkyl group having 1 to 8 C atoms, preferably a methyl or an ethyl group, in particular a methyl group;

R ^{2 is} an alkyl group having 1 to 5 C atoms, preferably a methyl group or an ethyl group or an isopropyl group, in particular a methyl group or an ethyl group, R ^{3 is} a linear or branched alkylene group having 1 to 4 C. Atoms, in particular for propylene,

R ^{4 is} H or a linear or branched alkyl group having 1 to 10 C atoms or a substituent of the formula (II)

R ^{5 is} H or a linear or branched alkyl group having 1 to 10 C

Atoms or for a linear or branched alkyl group having 1 to 10 carbon atoms with further heteroatoms or for a substituent of the formula

(N)

and wherein a is 0, 1 or 2, in particular 0 or 1, preferably 0.

7. Organoalkoxysilane according to claim 6, characterized in that R ^{5 is} CH ₂ CH ₂ NH ₂ .

8. Organoalkoxysilane composition according to claim 6, characterized in that the aminosilane is selected from the group comprising aminosilanes of the formula (III), (IV) and (V)

9. Organoalkoxysilane composition according to claim 5, characterized in that the aminosilane is a reaction product of an aminosilane of the formula (I) as described in claim 6 or 7 or 8 and which has at least one secondary or primary amino group, with a compound (ARV ) which contains at least one functional group which can react with a primary or secondary amino group.

10. An organoalkoxysilane composition according to claim 9, characterized in that the functional group which can react with a primary or secondary amino group is an epoxy group.

11. Organoalkoxysilane composition according to claim 5, characterized in that the aminosilane is a reaction product of a

Amino silane of formula (III) or (IV) as described in claim 8 with an epoxy group-containing compound.

12. Organoalkoxysilanzusammensetzung according to claim 10 or 11, characterized in that the epoxy group-containing compound is an epoxy silane, in particular an epoxy silane of the formula (VI), is

where R ^{1 is} an alkyl group having 1 to 8 C atoms, preferably a

Methyl or for an ethyl group, in particular a methyl group;

R ^{2 is} an alkyl group having 1 to 5 C atoms, preferably one

Methyl group or for an ethyl group or for an isopropyl group, in particular for a methyl group or for an ethyl group,

R ^{3 is} a linear or branched alkylene group having 1 to 4 C atoms, in particular propylene, and wherein a 'is O, 1 or 2, in particular 0 or 1, preferably 0.

13. An organoalkoxysilane composition according to any one of claims 6 to 12, characterized in that a = 0 and R ^{2 is} methyl and R ^{3 is} propylene.

14. Use of the Organoalkoxysilanzusammensetzung according to any one of claims 1 to 13 as a primer.

15. Use of the Organoalkoxysilanzusammensetzung according to any one of claims 1 to 13 as a pretreatment agent to be bonded or sealed substrate surfaces to improve the adhesion of an applied adhesive or sealant.

16. Use of the Organoalkoxysilanzusammensetzung according to any one of claims 1 to 13 for the preparation of an aqueous pretreatment agent for improving the adhesion of adhesives.