WO2000059975A1

WO2000059975A1 - Polyurethane dispersions with alkoxysilane terminal groups for glass fiber sizing agents

Info

Publication number: WO2000059975A1
Application number: PCT/EP2000/002485
Authority: WO
Inventors: Harald Blum; Karin Naujoks
Original assignee: Bayer Aktiengesellschaft
Priority date: 1999-04-01
Filing date: 2000-03-21
Publication date: 2000-10-12
Also published as: DE19914884A1; AU3557200A

Abstract

The invention relates to polyurethane dispersions that contain alkoxysilane terminal groups, a method for producing such dispersions and their use in or as sizing agents.

Description

Polyurethane dispersions with alkoxysilane end groups for glass fiber sizing

The invention relates to polyurethane dispersions containing alkoxysilane end groups, a process for the preparation of such dispersions and their use in or as sizes.

Polyurethane dispersions that can be crosslinked at room temperature with alkoxysilane groups, which harden to hard, water- or solvent-resistant and scratch-resistant lacquers and e.g. are well suited for painting wood, (PVC) floors, metallic substrates and for road marking paints, e.g. known from WO 94/13723. Such dispersions are less suitable for glass fiber sizes, primarily because of their molecular structure and high crosslinking, as are those described in US Pat. No. 5,554,686, curable at room temperature and purely ionic, preferably with carboxylate groups, and hydrophilized silane-terminated polyurethane Dispersions. Such dispersions do not have sufficient stability in size formulations, and carboxylate hydrophilization also promotes the susceptibility to hydrolysis of corresponding glass fiber reinforced plastics. This can lead to rapid degradation of the mechanical properties of the plastics.

EP-A 814 105 describes silane-functional polyurethane dispersions based on special polyesters, isocyanate-functional adducts and silane-functional polyisocyanates, as well as their use in two-component paints for painting metallic substrates. Two-component paints require separate storage of two components, which are only mixed shortly before application. This is associated with increased effort and involves the risk of reduced properties due to mixing errors. Such products are not suitable for glass fiber sizing. US Pat. No. 5,041,494 describes cationically hydrophilized polyurethane dispersions with pH values of 3 to 6 and higher contents of alkoxysilane groups (defined by a content of at least 1.3% by weight of SiO ₃ structural elements) which dry the coatings to be crosslinked .

US Pat. No. 3,941,733 describes curable, silanol group-containing polyurethane dispersions which are purely ionically hydrophilized and no chain extension reagents are used in their preparation. With such products, due to the chain extension due to the isocyanate-water reaction, product properties that are difficult to reproduce and due to the ionic hydrophilization, stability problems in conventional sizing recipes must be expected.

US Pat. No. 4,582,873 describes a process for the production of water-dispersible polyurethanes with pendant reactive siliconate anion structures, which are obtained in the production by preferably using difunctional organosilanes.

WO 90/10026 describes alkoxysilane group-terminated polyurethanes, produced from hydrophilic polyethylene glycols, hydrophobic polyols, polyisocyanate and alkoxysilane, chain extension reactions not being carried out.

The products are suitable for the finishing of textile fibers containing polyester.

There is still a need for improved polyurethane dispersions for glass fiber sizes, which above all have to have good processing properties and good reinforcement properties when used in glass fiber reinforced plastics.

Surprisingly, it has now been found that glass fiber sizes which contain special polyurethane dispersions with alkoxysilane end groups have improved application properties and improved processability of glass sizes fibers and show very good mechanical properties of corresponding glass fiber reinforced plastics.

Surprisingly, it was found that special polyurethane dispersions, which contain a predominantly linear structure, a high molecular weight and exclusively free alkoxysilane groups in a relatively low amount, enable the production of high-quality glass fiber sizes.

The polyurethane dispersions according to the invention in particular show excellent adhesion to glass, glass fibers or glass-like substrates. Surprisingly, glass fibers sized with the dispersions according to the invention show a particularly low and thus advantageous styrene solubility when used in thermoset reinforcement.

The mechanical properties of corresponding, reinforced plastics are very good. The resistance to hydrolysis is also good.

Because of the small amount of alkoxysilane end groups, crosslinking reactions occur after application - if at all - only to a very limited extent. The coatings are therefore not cross-linked, nor do they show scratch resistance or pronounced resistance to solvents.

All the more surprising is the excellent suitability of the polyurethane dispersions according to the invention for sizes or for coating glass.

For the sake of simplicity, the dispersions according to the invention are referred to as polyurethane dispersions, but they also contain urea or polyurea segments. The term dispersion also includes dispersions which contain dissolved polymer components. The proportion of dissolved polymers can be influenced, for example, by the molecular weight or the content of hydrophilizing components. The invention therefore relates to special polyurethane dispersions for glass fiber sizes with alkoxysilane end groups, which are obtained by chain extension of an isocyanate-functional prepolymer and subsequent chain termination reaction with a monamino-functional alkoxysilane.

The polyurethane dispersions according to the invention with alkoxysilane end groups are reaction products present in dispersed or dissolved form

a) at least one polyol component,

b) at least one di- and / or polyisocyanate component,

c) at least one hydrophilic, nonionic structural component, consisting of compounds with at least one group reactive towards isocyanate groups and at least one hydrophilic polyether chain and optionally at least one (potentially) ionic compound with at least one, optionally at least partially neutralized, salt-forming group and at least one group reactive towards isocyanate groups,

d) optionally one or two low molecular weight structural components of the molecular weight range 62 to 450 which differ from a) to c) and have at least two groups which are reactive toward isocyanate groups,

e) at least one chain extension component of molecular weight 32 to 350 with at least two groups reactive toward isocyanate groups,

f) optionally a monofunctional blocking agent and g) at least one monoamino-functional alkoxysilane as chain termination reagent,

component (s) c) being used in such an amount that a stable dispersion is formed.

The polyurethane dispersions according to the invention with alkoxysilane end groups are preferably reaction products present in dispersed or dissolved form

a) 40 to 75% by weight of at least one polyol component in the hydroxyl number range 5 to 350,

b) 10 to 45% by weight of at least one di-, tri- and / or polyisocyanate component,

c) 4 to 22% by weight of hydrophilic structural components, consisting of at least one hydrophilic, nonionic compound with at least one group reactive toward isocyanate groups and at least one hydrophilic polyether chain and optionally at least one (potentially) ionic

Compound with a group capable of salt formation which is optionally at least partially neutralized and at least one group which is reactive towards isocyanate groups,

d) 0 to 5% by weight of one or two structural components of the molecular weight range 62 to 450 which differ from a) to c) and have at least two groups which are reactive toward isocyanate groups,

e) 0.1 to 7.5% by weight of at least one chain extension component of molecular weight 32 to 350 with at least two groups reactive toward isocyanate groups, f) 0 to 7% by weight of a monofunctional blocking agent and

g) 0.25 to 10% by weight of at least one monomino-functional alkoxysilane as chain termination reagent,

wherein components (n) c) are used in such an amount that a stable dispersion is formed.

The polyurethane dispersions according to the invention with alkoxysilane end groups are particularly preferably reaction products present in dispersed or dissolved form

a) 40 to 69% by weight of at least one polyol component in the hydroxyl number range 5 to 350,

b) 12 to 35% by weight of at least one di-, tri- and / or polyisocyanate component,

c) 6 to 18% by weight of hydrophilic structural components, consisting of at least one hydrophilic, nonionic compound with at least one group reactive toward isocyanate groups and at least one hydrophilic polyether chain and optionally at least one (potentially) ionic compound with an optionally at least partially neutralized present group capable of salt formation,

d) 0 to 3% by weight of one or two structural components of the molecular weight range 62 to 450 which differ from a) to c) and have at least two groups which are reactive toward isocyanate groups, e) 0.2 to 6.0% by weight of at least one chain extension component of molecular weight 32 to 350 with at least two groups which are reactive toward isocyanate groups,

f) 0 to 3.5 wt .-% of a mono-functional blocking agent and

g) 0.5 to 5% by weight of at least one monomino-functional alkoxysilane as chain termination reagent,

Components c) are used in such an amount that a stable dispersion is formed.

The polyurethane dispersions according to the invention with alkoxysilane end groups are very particularly preferably reaction products present in dispersed or dissolved form

b) 12 to 35% by weight of at least one aliphatic and or cycloaliphatic

Diisocyanate component of molecular weight 168 to 262,

c) 6 to 18% by weight of hydrophilic structural components, consisting of a hydrophilic, non-ionic compound with a group reactive towards isocyanate groups and a hydrophilic polyether chain, and an ionic compound with an at least partially neutralized sulphonic acid group and two with isocyanate groups reactive groups, d) 0 to 3% by weight% by weight of one or two structural components of the molecular weight range 62 to 450 which differ from a) to c) and have at least two groups which are reactive toward isocyanate groups,

e) 0.2 to 6.0% by weight of at least one chain extension component of molecular weight 32 to 350 with two or three primary and / or secondary amino groups reactive towards isocyanate groups,

f) 0 to 3.5% by weight of a monofunctional blocking agent and

g) 0.75 to 3% by weight of a monoamino-functional alkoxysilane as chain termination reagent,

wherein components (n) c) are used in such an amount that a stable dispersion is formed, and all neutralizing agents are added before the dispersion.

The invention also relates to a process for the preparation of polyurethane dispersions containing alkoxysilane end groups, characterized in that first an isocyanate component is obtained from at least one polyol a), at least one isocyanate component b) optionally with the use of hydrophilizing components c) or component d). functional prepolymer is produced, then a part of the remaining isocyanate groups is reacted either in organic solution or after dispersing with a chain extension component e), optionally a hydrophilizing component c) and optionally a blocking agent f) and then the remaining isocyanate groups either before, during or after the dispersion with a monoamino-functional alkoxysilane g) are reacted and then the solvent which may have been added before, during or after the prepolymer preparation is removed, if appropriate by distillation. In a process variant, trifunctional or higher-functional polyisocyanates are first reacted with such amounts of monofunctional alkoxysilanes, which results in a difunctional alkoxysilane-modified isocyanate component bg), which contains at least one polyol a) optionally a diisocyanate component b), at least one hydrophilizing component c) and optionally a component d) converted to an isocyanate-functional prepolymer, then a part of the remaining isocyanate groups either in organic solution or after dispersing with a chain extension component e), optionally with a hydrophilizing component c) and optionally a blocking agent f) and then the before , during or after the prepolymer preparation, any added solvent is optionally removed by distillation.

The invention also relates to the use of special polyurethane dispersions with alkoxysilane end groups in or as sizes, in particular for glass fibers.

The invention also relates to the use of special polyurethane dispersions with alkoxysilane end groups in or as a coating and / or lacquer.

The invention also relates to the use of special polyurethane dispersions with alkoxysilane end groups in combination with blocked polyisocyanate crosslinkers in or as sizes, in particular sizes for glass fibers.

The invention also relates to the use of special polyurethane dispersions with alkoxysilane end groups and those blocked to the polymer

Isocyanate groups in or as sizes, in particular sizes for glass fibers.

Polyol components a) suitable for producing the dispersions according to the invention are, for example, polyester polyols (for example Ulimann's Encyclopedia of Industrial Chemistry, 4th edition, volume 19, pp. 62-65). Suitable raw materials for the production of these polyester polyols are difunctional alcohols such as ethylene glycol, 1,2- and 1,3-propylene glycol, 1,3-, 1,4-, 2,3-butanediol, 1, 6-hexanediol, neopentyl glycol, trimethylhexanediol, triethylene glycol, hydrogenated bisphenols, trimethylpentanediol, diethylenediglycol, dipropylenediglycol, 1, 4-cyclohexanediol, 1 , 4-cyclohexanedimethanol and difunctional carboxylic acids or their anhydrides such as adipic acid, phthalic acid (anhydride), isophthalic acid, maleic acid (anhydride), terephthalic acid, tetrahydrophthalic acid (anhydride), hexahydrophthalic acid (anhydride), bernic acid (anhydride), fumaric acid Azelaic acid, dimer fatty acid. Likewise suitable polyester raw materials are monocarboxylic acids such as benzoic acid, 2-ethylhexanoic acid, oleic acid, soybean oil fatty acid, stearin fatty acid, peanut oil fatty acid, linseed oil fatty acid, nonanoic acid, cyclohexane monocarboxylic acid, isononanoic acid, sorbic acid, conjuene fatty acid, higher-functional carboxylic acids or alcoholic acid carboxylic acid, tri-anhydride acid, trimellitic acid carboxylic acid, trimellitic acid, trimellitic acid, trimellitic acid, trimellitic acid, trimellitic acid, trimellitic acid, trimellitic acid, trimellitic acid, trimellitic carbonic acid, trimellitic acid, trimellitic acid, trimellitic carbonic acid, trimellitic acid, trimellitic acid, as well Trimethylolpropane, glycerin, pentaerythritol, castor oil, dipentaerythritol and other polyester raw materials not mentioned by name.

Also suitable polyol components a) are polycarbonate diols which e.g.

Reaction of diphenyl or dimethyl carbonate with low molecular weight di- or triols or ε-caprolactone-modified di- or triols can be obtained.

Lactone-based polyester diols are also suitable, these being homopolymers or copolymers of lactones, preferably addition products of lactones having terminal hydroxyl groups, such as e.g. ε-caprolactone or gamma-butyrolactone acts on difunctional starter molecules. Suitable starter molecules can be the diols mentioned above, but also low molecular weight polyester or polyether diols. Instead of the polymers of lactones, the corresponding hydroxycarboxylic acids can also be used.

Also suitable polyol components a) are polyether polyols. They are in particular by polymerization of ethylene oxide, propylene oxide, tetrahydrofuran, styrene oxide and / or epichlorohydrin with themselves, for example in the presence of BF ₃ or basic catalysts or by addition of these compounds, if appropriate also in a mixture or in succession, on starter components with reaction capable hydrogen atoms, such as alcohols, amines, amino alcohols or water available.

The polyol components a) mentioned can also be used as mixtures, if appropriate also together with other polyols a) such as Polyester amides, polyether esters,

Polyacrylates, polyols based on epoxy resin, are used.

The hydroxyl number of the polyols a) is 5 to 350, preferably 8 to 200 mg KOH / g substance. The molecular weights of the polyols a) are between 300 and 25,000, preferably between 300 and 15,000, in a preferred embodiment at least partially using polyols a) with a molecular weight of> 9000 g / mol.

Hydrolysis-stable polyols of molecular weight 300 to 3500 based on carbonate diols, tetrahydrofuran diols and or di- or trifunctional polyethers based on propylene oxide or propylene oxide / ethylene oxide or mixtures of the hydrolysis-stable polyols mentioned are preferably used as component a), when used trifunctional polyether polyols, these are used at most in amounts of up to 4% by weight based on the total solids content of the polymer.

These hydrolysis-stable polyols can also preferably be used together with minor amounts of polyester polyols with comparatively good hydrolysis stability, e.g. Polyesters based on phthalic anhydride, isophalic acid, dimer fatty acid, hexanediol and / or neopentyl glycol can be used.

Polyols based on polyester with molecular weights of 400 to 950 are preferably used as component a), optionally also as a mixture of polyesters with a molecular weight of 400 to 950 and other polyols mentioned above. In a particularly preferred embodiment, component a) is used in amounts of 40 to 49% by weight.

The total proportion of tri- or, less preferably, higher-functional components a) to g) is 0 to 6, preferably 0 to 4,% by weight, based on the total solids content of the polymer.

Component b) consists of at least one organic di-, tri- or poly-isocyanate with a molecular weight of 140 to 1500, preferably 168 to 262. For example, hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI) ^, 4,4'-diisocyanate dicyclohexyl are suitable -methane (H12MDI), 1,4-butane diisocyanate, hexahydrodiisocyanatotoluene, hexahydrodiisocyanatoxylol, nonane triisocyanate. In principle suitable, but not preferred are aromatic isocyanates such as 2,4- or 2,6-Diisocyana- totoluol (TDI), xylylene diisocyanate and ^{4,4'-diisocyanatodiphenylmethane.} Also known can be used polyisocyanates based on the aforementioned and also other isocyanates with uretdione, biuret, allophanate, isocyanurate, iminoxadiazinedione or urethane structural units, but this is not preferred.

The exclusive use of aliphatic and / or cycloaliphatic difunctional isocyanates having a molecular weight of 168 to 222 is particularly preferred, in particular isophorone diisocyanate and / or hexamethylene diisocyanate and / or diisocyanatodicyclohexylmethane (Desmodur® W, Bayer AG).

Component c) consists of at least one hydrophilic, nonionic structural component, consisting of compounds with at least one group reactive toward isocyanate groups and at least one hydrophilic polyether chain and optionally at least one (potentially) ionic compound with at least one, optionally at least partially neutralized, capable of salt formation Group and at least one group reactive towards isocyanate groups. The ionic compounds c) are, for example, at least one, preferably one or two hydroxyl and / or primary or secondary amino groups having carboxylic acid, sulfonic acid and phosphoric acid or salts thereof. Suitable acids are, for example, hydroxypivalic acid, dimethylolacetic acid, ^{'thylolpropionsäure} -Dime-, 2,2'-dimethylolbutyric acid, aminobenzoic acid, ^2,2' 2,2-dimethyl olpentansäure, addition products of acrylic acid and diamines such as ethylene diamine or isophorone diamine. Likewise suitable is the use of sulfonate diols, optionally containing ether groups, of the type described in US Pat. No. 4,108,814. Amino-functional sulfonates with one or two reactive, ie primary or secondary, amino groups are also suitable.

The free acid groups, in particular carboxyl and sulfonic acid groups, represent the “potentially ionic or anionic” groups mentioned above, while the salt-like groups obtained by neutralization with bases or acids

Groups, in particular carboxylate groups and sulfonate groups, are the “ionic or anionic” groups mentioned above.

In a preferred embodiment, anionic components c) consist of the addition product of equivalent amounts of acrylic acid and isophoronediamine.

This results in favorable compatibility, a reduced tendency to crystallize the polymer and improved application properties.

In a particularly preferred embodiment, anionic components c) consist of compounds containing sulphonate groups with one or preferably two reactive hydroxyl or amino groups.

This improves the compatibility with other binder components and has a positive influence on the hydrolysis resistance and the stability of the sizes. (Potentially) anionic component c) with two or three reactive primary and / or secondary amino groups can also be used as chain extension component e).

Nonionic hydrophilic compounds c) are mandatory and have pro

Molecule one or two groups reactive towards isocyanate groups, in particular hydroxyl and / or primary or secondary amino groups, and at least one hydrophilic polyether chain. The polyether chains of these compounds consist of 30% to 100% of built-in ethylene oxide units, in a preferred embodiment 40 to 95% of built-in ethylene oxide units in addition to 5 to 60% of built-in propylene oxide units. Suitable such components c) have molecular weights of 300 to 6000 and are e.g. monofunctional polyethylene propylene glycol monoalkyl ethers such as Breox® 350, 550, 750 from BP Chemicals, polyether LB 25, LB 30, LB 34, LB 40 from Bayer AG, polyethylene / propylene glycols such as Carbowax® 300, 400, 1000, 2000, 6000 from Union Carbide, di- or monofunctional polyetheramines such as Jeffamine® ED600, ED900, ED4000, M715, Ml 000, M2070 from Texaco.

Nonionic monofunctional components c) with a molecular weight of 1000 to 2500 with a built-in propylene oxide content of 10 to are preferred

57% and a built-in ethylene oxide content of 90 to 43%.

A mixed hydrophilization of nonionic hydrophilic components c) in amounts of 4 to 15% by weight and anionic components c) with carboxylate groups, preferably from the reaction product of isophoronediamine and acrylic acid in amounts of 0.5 to 6% by weight, is preferably used.

Mixed hydrophilization of nonionic hydrophilic components c) in amounts of 4 to 15% by weight and anionic components c) with sulfonate groups in amounts of 0.5 to 6% by weight is particularly preferably used. Purely nonionic hydrophilization by components c) in amounts of 15 to 21% by weight is also particularly preferred.

Component d) is a low molecular weight structural component of molecular weight range 62 to 450 which differs from a), b) and c) and has at least two groups which are reactive toward isocyanate groups. These reactive groups are preferably hydroxyl groups.

Suitable components d) are e.g. Ethylene glycol, 1,2-, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1, 6-hexanediol, trimethylpentanediol, trimethylolpropane, glycerol, the reaction product of 2 moles of propylene carbonate and 1 mole of hydrazine and / or Mixtures of those mentioned, if appropriate also with further components d). Components d) are used in amounts of 0 to 5, preferably 0 to 3% by weight 2.

Component e) is at least one chain extension component of molecular weight 32 to 350 which differs from a) to d) and has at least two groups which are reactive toward isocyanate groups. Reactive groups are preferably primary or secondary amino groups. Suitable components e) are e.g. Ethylenediamine, diethylenetriamine, isophoronediamine, hexamethylenediamine, 4,4-diaminodicyclohexylmethane, hydroxyethylethylenediamine, ethanolamine, diethanolamine, isopropanolamine, diisopropanolamine, N-methylethanolamine, aminomethylpropanol, hydrazine (hydrate), propylenediamine or diamine, mixtures of di-ethylenediamine, diamine diamine, mixtures of adiaminodiamine or diamine diamine, mixtures of adiaminodiamine or diamine diamine, mixtures of adiaminodiamine or diamine diamine diamine, mixtures of adiaminodiamine or diamine diamine diamine, mixtures of adiaminodiamine or diamine diamine diamine, mixtures of dimethyl adiamine diamine, the said, optionally also with other components e). Components e) are used in amounts of 0.15 to 5, preferably from 0.2 to 3.5 and very preferably from 0.2 to 2.5% by weight.

Difunctional amines are preferably used, optionally in combination with a triamine. In a preferred embodiment, 0.1 to 1.0% by weight of hydrazine or an equivalent amount of hydrazine hydrate, optionally in combination with other components e) mentioned above, is used as chain extender e).

Di- and / or trifunctional (potentially) anionic components c) with two or three reactive primary and / or secondary amino groups, such as e.g. 2-aminoethylaminoethane sulphonate or the 1: 1 reaction product of acrylic acid and isophoronediamine can also be used as chain extension reagent e). This can be done in combination with other compounds e) mentioned above, but component c) can also act as the sole chain extension reagent e).

By suitable selection of component e), the molecular weight build-up can be influenced by chain extension or chain branching and high molecular weights can be built up in a defined manner.

Suitable monofunctional blocking agents f) can e.g. be: butanone oxime, cyclohexanone oxime, acetone oxime, malonic ester, triazole, ε-caprolactam, phenol, dimethylpyrazole, monofunctional amines such as di-butylamine, di-isopropylamine, monofunctional alcohols such as e.g. Butanol, cyclohexanol, isopropanol, tert-butanol. Mixtures of different blocking agents can also be used, in particular mixtures of blocking agents which unblock at different temperatures and thus enable a preferred embodiment, a stepwise reaction.

Preferred blocking agents are butanone oxime, epsilon-caprolactone, dimethylpyrazole and alcohols or mixtures of these blocking agents. The blocking agents can be used in amounts of 0 to 7, preferably 0 to 4,% by weight. In the preparation of the dispersions according to the invention, one equivalent of a trifunctional chain extender e) is used for each equivalent of a blocking agent, if appropriate, in order to achieve the desired high molecular weights.

Suitable monoamino-functional alkoxysilanes as chain termination component g) are e.g. 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltributoxysilane, 2-aminoethyltriethoxysilane, 2-aminoethyltrimethoxysilane, 2-aminoethyltributoxysilane, 4-aminobutyltriethoxysilane, 4-aminobutylmethyl oxysilane, reaction products of the alkoxysilanes mentioned with dialkyl malonates such as, for example Diethyl malonate, dimethyl malonate or dibutyl malonate, compounds of the type mentioned in which one or two of the alkoxy groups have been replaced by alkyl groups and mixtures of the said and other alkoxysilanes. Component e) is used in amounts of 0.25 to 10, preferably 0.5 to 5, particularly preferably 0.75 to 3% by weight.

In a particularly preferred embodiment, the mathematically determined content of -Si- (O-) _{3 in} the solid of the polyurethane dispersions is less than 1.25% by weight.

In a preferred embodiment, chain extenders e), optionally blocking agents f) and monoamino-functional alkoxysilanes g) are used in amounts of 35 to 85 equivalent percent of reactive amino and / or hydroxyl groups, based on the free isocyanate groups of the prepolymer

Components a) to d) used. That that the amount of isocyanate-reactive groups in e), f), and g) is 35 to 85% of the amount of reactive isocyanate groups of the prepolymer from a) to d).

In a further preferred embodiment, the inventive

Dispersions of differently blocked isocyanate groups, the isocyanate groups unblock at different temperatures and thus contribute to a good bond of glass fibers to the size and in the second step to a good bond of the sized glass fibers to plastic.

The polyurethane dispersions according to the invention with alkoxysilane groups show a practical storage stability at room temperature up to 65 ° C. After application, drying takes place at temperatures of 90 to 280 ° C, preferably at 110 to 200 ° C.

The dispersions according to the invention are prepared in such a way that an isocyanate-functional prepolymer is first prepared from at least one polyol a), at least one isocyanate component b), optionally with the use of hydrophilizing components c) or a component d), then part of the remaining isocyanate groups either in organic solution or after dispersing with a chain extension component e), optionally a hydrophilizing component c) and optionally a blocking agent f) and then reacting the other isocyanate groups either before, during or after the dispersion with a monoaminofunctional alkoxysilane g) and then the solvent which may have been added before, during or after the prepolymer preparation is removed, if appropriate by distillation.

In a preferred process variant, at least one polyol a), at least one diisocyanate b) is converted into a monohydroxy-functional, nonionic hydrophilization component c), if appropriate a mono- or dihydroxy-functional (potentially) anionic hydrophilization component c) and if appropriate di- and / or trihydroxy-functional components d) an isoeyanate-functional prepolymer is produced, this either before dispersing, then in the presence of solvent, or after dispersing, first with the chain extender e) and optionally f) and then with the chain terminator g) Reaction, and then before, during or any solvent added, if any, after the prepolymer preparation is removed by distillation, the total amount of neutralizing agent being added before the dispersion.

In a further preferred process variant, an isocyanate-functional prepolymer is first prepared from at least one polyol a), at least one diisocyanate b), a monohydroxy-functional, nonionic hydrophilization component c) and, if appropriate, di- and / or trihydroxy-functional components d), this then either before dispersing, then in the presence of solvent, or after dispersing, first of all reacted with a mixture of a diamino-functional (potentially) ionic hydrophilizing agent c) and chain extender e) and optionally f) and then reacted with the chain terminating agent g), and then the solvent which may have been added before, during or after the prepolymer preparation is removed, if appropriate by distillation, the total amount of neutralizing agent before

Dispersing is added.

In a further process variant, trifunctional or higher-functional polyisocyanates are first reacted with such amounts of monofunctional alkoxysilanes that a difunctional alkoxysilane-modified isocyanate component bg) results, which contains at least one polyol a) optionally a diisocyanate component b), at least one hydrophilizing component c) and optionally one Component d) converted to an isocyanate-functional prepolymer, then part of the remaining isocyanate groups either in organic solution or after dispersing with a chain extension component e), optionally one

(Potentially) anionic hydrophilization component c) and optionally a blocking agent f) and then the solvent which may have been added before, during or after the prepolymer preparation is optionally removed by distillation. The reaction of the components can be carried out with the addition of catalysts such as dibutyltin dilaurate, tin 2-octoate, dibutyltin oxide or diazabicyclononane.

For converting the acid groups into salt groups, for example, amines such as triethylamine, N-methylmoφholin, diisopropylamine, hydroxyamines such as diethanolamine, triethanolamine, diispropanolamine, aminomethylpropanol, potassium or sodium hydroxide, ammonia and di- or polyamines such as hexamethylenediamine, isophoronediamine, isophoronediamine, 4-cyclohexanediamine, trimethylhexanediamine, Dimethylhexandiamin, Jeffamine ^® (Texaco), such as 3,3 '- [l, 4-butanediyl bis (oxy)] bis-l-propanamine, 4,4'-methylene-bis- (2, 6-diethylcyclo-hexanamine), 4,4 ^λ - methylene-bis- (2-methylcyclohexanamine), 4,4'-methyl en-bis-cyclohexane-amine can be used.

The degrees of neutralization are generally between 40 and 120%, preferably 100 to 120%.

In a preferred embodiment, the complete amount of neutralizing agent is added even before the prepolymer or polymer is dispersed in / with water.

After dispersing in / by water, the mixture is stirred until all the isocyanate groups which may still be present have reacted. It is also possible to completely react all isocyanate groups with the above-mentioned components before dispersing them in / with water.

The solvents which may be used to prepare the dispersion can be partially or preferably completely removed from the dispersion by distillation. The dispersions particularly preferably contain less than 2% by weight of volatile solvents and neutralizing agents. Preferred solvents are in particular

Acetone or methyl ethyl ketone, but also N-methyl pyrrolidone. If necessary, auxiliaries and additives, such as anti-settling agents, defoamers, thickeners, emulsifiers, catalysts, flow control agents, adhesion promoters, biocides, antistatic agents, light stabilizers, lubricants, thermal stabilizers, etc., but also special oligo- mer or polymeric compounds with or without hydrophilic groups are added.

The dispersions according to the invention have average particle diameters (determined, for example, by laser correlation spectroscopy) from 20 to 900, preferably from

50 to 400 nm.

The solids content of the dispersions is at least 30% at viscosities of 10 to 150 seconds run-off time (DIN-4 cup, 23 ° C.). The pH values are preferably between 5.0 and 11.0.

The dispersions according to the invention are particularly suitable for use in or as sizes, preferably glass fiber sizes. The dispersions can be used as the sole binder or together with other polymers such as e.g. Polyurethane dispersions, polyacrylate dispersions, polyester dispersions, polyether dispersions,

Polyepoxide dispersions, polyvinyl ester or polyvinyl ether dispersions, polystyrene or polyacrylonitrile dispersions, blocked polyisocyanates, blocked polyisocyanate dispersions, amino crosslinking resins such as e.g. Melamine resins are used.

In a preferred embodiment, the dispersions according to the invention are used in combination with blocked polyisocyanates based on hexamethylene diisocyanate, isophorone diisocyanate and / or Desmodur W which may contain hydrophilic groups. The preferred mixing ratio of the dispersion according to the invention to polyisocyanate crosslinking agent is 65% to 35% to 10% by weight, based in each case on the solids content.

Suitable blocking agents for these polyisocyanate crosslinkers are e.g. Butanone oxime, ε-caprolactam or dimethylpyrrazole. Suitable hydrophilizing agents are, above all, the ionic or nonionic compounds mentioned in component c), in particular those having one or two hydroxyl groups available for reaction with isocyanate groups.

The dispersions according to the invention or the sizes produced therewith can contain the usual auxiliaries and additives, such as e.g. Defoaming agents, thickening agents, flow control agents, dispersing aids, catalysts, skin preventing agents, anti-settling agents, emulsifiers, biocides, adhesion promoters, e.g. based on the known low or high molecular weight silanes, lubricants, wetting agents,

Antistatic.

The sizes can be applied by any method, for example with the help of suitable devices such as spray or roller applicators. They can be applied to the glass filaments drawn from spinnerets at high speed immediately after they have solidified, ie before they are wound up. It is also possible to size the fibers in an immersion bath after the spinning process. The sized glass fibers can be processed either wet or dry, for example into chopped glass. The final or intermediate product is dried at elevated temperatures. Drying is not only to be understood to mean the removal of other volatile components, but also, for example, the setting of the size components. The proportion of the size is 0.1 to 4%, preferably 0.2 to 2% by weight, based on the sized glass fibers. Both thermoplastic and thermoset polymers can be used as matrix polymers.

The dispersions according to the invention obtained are furthermore suitable for all fields of use in which solvent-containing, solvent-free or other types of aqueous

Painting and coating systems with an increased property profile are used, e.g. Coating of mineral substrates, painting and sealing of wood and wood-based materials, painting and coating of metallic surfaces, painting and coating of plastics as well as coating of textiles and leather. The dispersions according to the invention can be used as

Primer, adhesive coat, adhesive primer, filler, top coat, single-coat paint, top coat or finish in the form of clear coats or clear coatings or in pigmented form is used.

Examples:

example 1

In a 6-1 reaction vessel with stirring, cooling and heating device, 1237 g of a difunctional adipic acid butanediol polyester with a molecular weight of 900 g / mol, 278 g of polyether LB25 (Bayer AG, monofunctional polyether based on ethylene oxide propylene oxide, molecular weight 2245 g / Mol), 27.2 g of 1,4-butanediol and 116.4 g of a sodium sulphonate diol with a molecular weight of 432 g / mol, weighed at 75 ° C. and then mixed with 849 g of isophorone diisocyanate

100 ° C until the theoretical isocyanate value has been reached. After cooling to 75 ° C, the isocyanate - functional polyurethane prepolymer is dispersed in 10 minutes by adding 3300 g of distilled water. 15 minutes to extend the chain, a 25% aqueous solution of 8.0 g of hydrazine, 12.9 g of diethylenetriamine and 43.8 g of ethylenediamine was added and after

10 minutes reaction time, then a chain termination solution of 60.8 g of 3-aminopropyltriethoxysilane and 440 g of water is added in about 15 minutes and the mixture is stirred at 50 ° C. until no isocyanate groups can be detected by infrared spectroscopy. A finely divided polyurethane dispersion with alkoxysilane end groups is obtained which has a solids content of approx. 41% and a viscosity in the

DIN 4 flow cup (23 ° C) of 14 seconds and a pH of 6.6.

Example 2

1105 g of a polycarbonate diol with a molecular weight of 2000 g / mol (Desmophen C200, Bayer AG), 227.5 g of a difunctional polypropylene glycol with a molecular weight of 1000 and 365 g are placed in a 6-1 reaction vessel with a stirring, cooling and heating device Weighed in polyether LB25 (Bayer AG, monofunctional polyether based on ethylene oxide / propylene oxide, molecular weight 2245 g / mol), melted at 70 ° C. and then with 209 g isophorone diisocyanate and 152.9 g

Hexamethylene diisocyanate reacted until the theoretical isocyanate value has been achieved. The isocyanate-functional polyurethane prepolymer is then diluted with 1800 g of acetone and a 25% chain extension solution in water of 61.8 g of aminoethylaminoethanesulphonic acid in the form of the sodium salt, 2.3 g of hydrazine and 20.2 g of diethylenetriamine is rapidly added. The mixture is then dispersed by adding 3300 g of distilled water, followed by the addition of a

50% acetone solution of 42 g of the chain termination reagent 3-aminopropyltrimethoxysilane. When the addition is complete, the acetone is distilled off, an approximately 39% fine dispersion with a viscosity of 20 seconds is obtained (measured in a DIN 4 flow cup at 23 ° C.).

Example 3

In a 2-1 reaction vessel with stirring, cooling and heating device, 135 g of a difunctional polypropylene glycol with a molecular weight of 2000 g / mol, 135 g of a difunctional adipic acid-butanediol polyester with a molecular weight of 900, 43.9 g of polyether LB25 ( Bayer AG, monofunctional polyether based on ethylene oxide / propylene oxide, molecular weight 2245 g / mol) and 19.5 g of a sodium sulphonate diol with a molecular weight of 432 g / mol, weighed in, homogenized at 70 ° C. and then reacted with 124 g isophorone diisocyanate, until the theoretical isocyanate value has been reached. The isocyanate-functional polyurethane

The prepolymer is then diluted with 100 g of acetone and dispersed by adding 630 g of distilled water. A chain extension mixture of 1.5 g of diethylene triamine, 1.4 g of hydrazine, 20.6 g of isophoronediamine and 90 g of water is then added in 2 minutes. 10 minutes after the addition of the mixture, 7.2 g of 3-aminopropyltriethoxysilane dissolved in 20 g of water are added. After this

Distilling off the acetone gives a polyurethane dispersion with a solids content of 40% and a viscosity (flow time in a DIN 4 cup at 23 ° C.) of 25 seconds. Example 4

400 g of a difunctional tetrahydrofuran polyether with a molecular weight of 2000 g / mol, 28 g of polyether LB25 (Bayer AG, monofunctional polyether) are dissolved in a 3-1 reaction vessel with a stirring, cooling and heating device

Weighed in ethylene oxide / propylene oxide base, molecular weight 2245 g / mol) and 20.3 g butanediol, homogenized at 70 ° C., mixed with 169.8 g isophorone diisocyanate and reacted at 100 ° C. until the theoretical isocyanate value was reached. The isocyanate-functional polyurethane prepolymer is diluted with 800 g of acetone and then a chain extension solution consisting of 22.8 g of aminoethylaminoethanesulfonic acid in the form of the sodium salt, 3 g of ethylenediamine and 50 g of water is added. Then 11 g of 3-aminopropyltriethoxysilane are added, the mixture is dispersed by adding 900 g of distilled water and the acetone is removed by distillation. A polyurethane dispersion with a solids content of 41% and a viscosity of 18 seconds is obtained (DIN 4 flow cup, 23 ° C.).

Example 5

In a 10-1 reaction vessel with a stirring, cooling and heating device, 1377 g of a difunctional adipic acid-hexanediol-neopentylglycol polyester are mixed with the

Molecular weight 1700 g / mol and 365 g polyether LB25 (Bayer AG, monofunctional polyether based on ethylene oxide / propylene oxide, molecular weight 2245 g / mol) were weighed out and homogenized at 70.degree. Then 288 g of hexamethylene diisocyanate are added and the reaction is continued at 85 ° C. until the theoretical isocyanate value has been reached. The isocyanate-functional polyurethane prepolymer is diluted with 1400 g of acetone and then a chain extension solution consisting of 77 g of aminoethylaminoethanesulphonic acid in the form of the sodium salt, 4.4 g of hydrazine and 150 g of water is added. Then 41 g of 3-aminopropyltrimethoxysilane are added, the mixture is dispersed by adding 3700 g of distilled water and the acetone is removed by distillation. A very finely divided polyurethane dispersion is obtained. sion with a solids content of 34% and a viscosity of 12 seconds (DIN 4 flow cup, 23 ° C).

Example 6

1040 g of a difunctional polycarbonate diol with a molecular weight of 2000 g / mol (Desmophen® 2020, Bayer AG), 520 g of a difunctional phthalic anhydride-hexanediol polyester with a molecular weight of 2000 are placed in a 10-1 reaction vessel with a stirring, cooling and heating device and 234 g of polyether LB25 (Bayer AG, monofunctional polyether based on ethylene oxide / propylene oxide, molecular weight 2245 g / mol) were weighed in and homogenized at 70.degree. 369 g of Desmodur® W are then added and the mixture is reacted at 100 ° C. until the theoretical isocyanate value has been reached. The isocyanate-functional polyurethane prepolymer is diluted with 1900 g of acetone and then a chain extension solution consisting of 30 g of aminoethylaminoethanesulphonic acid in the form of the sodium salt, 35.6 g of isophoronediamine and 150 g of water is added. 20 minutes after the end of the addition, 23 g of 3-aminopropyltrimethoxysilane, diluted with 23 g of acetone, are added, dispersed by adding 3200 g of distilled water, and the acetone is removed by distillation. A finely divided polyurethane dispersion with a solids content of 42% and a viscosity of 19 seconds is obtained (DIN 4 flow cup, 23 ° C.).

Example 7

1000 g of a difunctional polycarbonate diol with a molecular weight of 2000 g / mol are placed in a 10 l reaction vessel with a stirring, cooling and heating device

(Desmophen 2020, Bayer AG), 700 g of a difunctional tetrahydrofuran polyether with a molecular weight of 2000, 300 g of a difunctional polypropylene glycol with a molecular weight of 2000 and 70 g of polyether LB25 (Bayer AG, monofunctional polyether based on ethylene oxide / propylene oxide, Molecular weight 2245 g / mol) weighed and homogenized at 70 ° C. Then with 281 g

Hexamethylene diisocyanate and 70 g of isophorone diisocyanate are added and at 100 ° C implemented until the theoretical isocyanate value has been reached. The isocyanate-functional polyurethane prepolymer is diluted with 1500 g of acetone and then a chain extension solution consisting of 3.2 g of hydrazine, 10.8 g of ethylenediamine and 20 g of water is added. 10 minutes after the end of the addition, 56.2 g of 1: 1 reaction product of 3-aminopropyltrimethoxysilane and dimethyl maleate are added, the mixture is dispersed by adding 4900 g of distilled water and the acetone is removed by distillation. A very finely divided polyurethane dispersion with a solids content of 33% and a viscosity of 40 seconds is obtained (DIN 4 flow cup, 23 ° C.).

Example 8

1200 g of a difunctional polycarbonate diol with a molecular weight of 2000 g / mol (Desmophen 2020, Bayer AG), 800 g of a difunctional polypropylene glycol with a molecular weight of 2000 and 70 g of polyether LB25 are placed in a 10 l reaction vessel with a stirring, cooling and heating device (Bayer AG, monofunctional polyether based on ethylene oxide / propylene oxide, molecular weight 2245 g / mol) and weighed at 70 ° C. Then 310 g of hexamethylene diisocyanate are added and the reaction is continued at 100 ° C. until the theoretical isocyanate value has been reached. The isocyanate-functional polyurethane prepolymer is included

2500 g of acetone were diluted and then a chain extension solution consisting of 138 g of the 1: 1 reaction product of isophoronediamine and acrylic acid and 150 g of water was added. When the addition has ended, 35 g of 3-aminopropyltriethoxysilane are metered in with vigorous stirring, dispersed by adding 3700 g of distilled water and the acetone is removed by distillation. A polyurethane dispersion with a solids content of 39% and a viscosity of 35 seconds is obtained (DIN 4 flow cup, 23 ° C.). Comparative Example 1

Example 1) is repeated, but the 3-aminopropyltriethoxysilane is omitted. A dispersion is obtained with a solids content of approx. 40%, a viscosity in the DIN 4 flow cup (23 ° C.) of 13 seconds and a pH of 7.1.

Comparative Example 2

Example 1) is repeated, but the order of addition of the chain extension solution or the chain termination solution is reversed, i.e. the chain termination solution is added first. A dispersion is obtained with a solids content of approximately 41%, a viscosity in the DIN 4 flow cup (23 ° C.) of 12 seconds and a pH of 7.0.

Comparative Example 3

Example 1) is repeated, but instead of the monoamino-functional 3-aminopropyltriethoxysilane, an equivalent amount of the difunctional aminoethylaminopropyltriethoxysilane is added together with the chain extension solution. A dispersion is obtained with a solids content of approx. 41%, a viscosity in the DIN 4 flow cup (23 ° C.) of 16 seconds and a pH of 7.8.

Dispersions according to Example 1) and from Comparative Examples 1), 2) and 3) are drawn with a film puller onto a) glass plates degreased with dichloromethane and onto b) glass plates cleaned in a dishwasher, in each case in layer thicknesses of 10 or 35 μm dry film, and applied once 24 hours at room temperature, and dried in a second test series for 5 minutes at 50 ° C and then for 5 minutes at 150 ° C. The adhesion of the coatings was then tested using a cross cut test in accordance with DIN 53 151:

Table 1; Cross cut test according to DIN 53 151

The values determined range from 0 (very good adhesion) to 5 (very poor adhesion). It can be seen that comparative dispersion 1), which as the only dispersion contains no alkoxysilane groups, has a significantly poorer adhesion than the three other dispersions.

This is particularly noticeable on the glass plates cleaned in the dishwasher, which presumably still have traces of detergent on the surface.

The dispersion according to Example 1) and the comparative dispersions 2) and 3) show overall good to very good adhesion values. However, it can be seen that the dispersion according to the invention tends to have the best adhesion, especially when the glass surface is not optimally cleaned.

Using the dispersions 1) according to the invention and the comparative dispersions 2) and 3), the usual auxiliaries, etc. a lubricant and 3-aminopropyltriethoxysilane as an adhesion promoter (10% based on the amount of dispersion used), glass fibers were prepared, sized, cut and dried in a customary and known manner. The glass fibers were compounded in polyamide 6.6 for reinforcement

The processing properties of the sizes based on the dispersion 1) according to the invention and the dispersion from comparative example 2) were very good. There were no problems with specks or dropouts during use. The processing of the dispersion according to Comparative Example 3) was not optimal; an increased tendency to form specks was observed, which considerably impedes safe, reproducible processing. A further test of the properties of the dispersion according to comparative example 3) was therefore dispensed with. The examination of the mechanical values of the test specimens produced using the glass fibers sized with dispersion according to Example 1) and Comparative Example 2) gave the following result:

Table 2: mechanical test

It can be seen that when using dispersion 1) compared to comparative dispersion 2), better mechanical values of the glass fiber reinforced plastic are obtained.

Sized glass fibers were produced using 85% by weight of dispersion 2) and 15% by weight of a nonionically hydrophilized and butanone oxime-blocked hexamethylene diisocyanate trimerate and these were compounded into polyamide. Test specimens produced therefrom were subjected to a hydrolysis test at 120 ° C. in a water / ethylene glycol mixture. The initial bending strength was approx. 280 MPa, after 2 weeks the bending strength was still approx. 160 MPa, after 4 weeks approx. 140 MPa and after 6 weeks still approx. 130 MPa. Overall, these values can be assessed as very good.

Coated glass fibers were produced using dispersion from Example 1), from Example 7) and from Comparative Example 1) and used to reinforce unsaturated polyester resins. The styrene solubility of the size during processing should be as low as possible. The following values were found:

Example 1): 18% Example 7): 23%

Comparative Example 1): 40%

The Chaφy Impact values of corresponding test specimens were determined as follows (given are not absolute values but percentage values, the best product being set at 100%):

Example 1): 100%

Example 7): 95%

Comparative Example 1): 85%

Overall, the polyurethane dispersions according to the invention allow the production of high quality glass fiber sizes for different areas of application and different requirement profiles.

Claims

1. Special polyurethane dispersions with alkoxysilane end groups, characterized in that they represent the reaction product, in dispersed and / or dissolved form, of an isocyanate-functional prepolymer first with chain-extending components and then with chain-terminating, monoaminofunctional alkoxysilanes.

2. Special polyurethane dispersions with alkoxysilane end groups according to

Claim 1), characterized in that they represent reaction products present in dispersed or dissolved form

a) at least one polyol component,

b) at least one di- and or polyisocyanate component,

c) at least one hydrophilic, nonionic structural component, consisting of compounds with at least one group reactive towards isocyanate groups and at least one hydrophilic polyether chain and optionally at least one (potentially) ionic compound with at least one, optionally at least partially neutralized, capable of salt formation Group and at least one group reactive towards isocyanate groups,

d) optionally one or two low molecular weight structural components of the molecular weight range 62 to 450 different from a) to c) with at least two groups reactive toward isocyanate groups and e) at least one chain extension component of molecular weight 32 to 350 different from a) to d) with at least two groups reactive toward isocyanate groups

f) optionally a monofunctional blocking agent and

g) at least one monoamino-functional alkoxysilane as chain termination reagent,

wherein component (s) c) is used in such an amount that a stable

Dispersion arises.

3. Polyurethane dispersions according to claims 1 and 2, characterized in that they represent reaction products present in dispersed or dissolved form

b) 10 to 45% by weight of at least one di-, tri- and or polyisocyanate component,

c) 4 to 22% by weight of hydrophilic structural components, consisting of at least one hydrophilic, nonionic compound with at least one group reactive toward isocyanate groups and at least one hydrophilic polyether chain and optionally at least one (potentially) ionic compound with an optionally at least partially neutralized one group capable of salt formation and at least one group which is reactive towards isocyanate groups, d) 0 to 5% by weight> one or two structural components of the molecular weight range 62 to 450 which differ from a) to c) and have at least two groups which are reactive toward isocyanate groups,

e) 0.1 to 5% by weight of at least one different from a) to d)

Chain extension component of molecular weight 32 to 350 with at least two groups reactive towards isocyanate groups,

f) 0 to 7 wt .-% of a monofunctional blocking agent and

where component (s) c) are used in such a quantity that a stable dispersion is formed.

4. Polyurethane dispersions according to claims 1 to 3, characterized in that they are present in dispersed or dissolved form of reaction products

c) 6 to 18% by weight of hydrophilic structural components, consisting of at least one hydrophilic, nonionic compound with at least one group reactive toward isocyanate groups and at least one hydrophilic polyether chain and optionally at least one (potentially) ionic compound with an optionally at least partially neutralized, salt-forming group and at least one group that is reactive towards isocyanate groups,

d) 0 to 3% by weight of one or two different from a) to c)

Structural component of the molecular weight range 62 to 450 with at least two groups reactive toward isocyanate groups,

e) 0.2 to 3.5% by weight> at least one chain extension component of molecular weight 32 to 350 which is different from a) to d) and has at least two groups which are reactive toward isocyanate groups,

f) 0 to 3.5% by weight of a monofunctional blocking agent and

5. Polyurethane dispersions according to claims 1 to 4, characterized in that they are present in dispersed or dissolved form of reaction products

b) 12 to 35% by weight of at least one aliphatic and or cycloaliphatic diisocyanate component with a molecular weight of 168 to 262, c) 6 to 18 wt .-%> hydrophilic structural components, consisting of a hydrophilic, nonionic compounds with a group reactive towards isocyanate groups and a hydrophilic polyether chain and an ionic compound with an at least partially neutralized sulphonic acid group and two opposite

Groups reactive to isocyanate groups,

d) 0 to 3% by weight of one or two structural components of the molecular weight range 62 to 450 which differ from a) to c) and have at least two groups which are reactive toward isocyanate groups,

e) 0.2 to 2.5% by weight of at least one chain extension component of molecular weight 32 to 350 which is different from a) to d) and has two or three groups which are reactive toward isocyanate groups,

f) 0 to 3.5% by weight of a monofunctional blocking agent and

g) 0.75 to 3% by weight of monoamino-functional alkoxysilane as chain termination reagent,

wherein component (s) c) is used in such an amount that a stable dispersion is formed, and wherein all neutralizing agents are added before the dispersion.

Polyurethane dispersions according to claims 1 to 5, characterized in that component a) consists of polycarbonate diols, polytetrahydrofuran diols and / or di- or trifunctional polypropylene glycols with a molecular weight of 300 to 3500, with a maximum of 4% trifunctional polyethene polyols based on the total solids content of the Polymers are included.

7. Polyurethane dispersions according to claims 1 to 5, characterized in that component a) contains polyester diols with a molecular weight of 400 to 950.

8. Polyurethane dispersions according to claims 1 to 5, characterized in that component a) is contained in amounts of 40 to 49 wt .-%.

9. Polyurethane dispersions according to claims 1 to 5, characterized in that isophorone diisocyanate and or hexamethylene diisocyanate and or diisocyanatodicyclohexy-methane is present as component b).

10. Polyurethane dispersions according to claims 1 to 5, characterized in that only sulfonate group-containing compounds having two hydroxyl and / or amino groups are present as anionic hydrophilization component c).

11. Polyurethane dispersions according to claims 1 to 5, characterized in that the anionic hydrophilization component c) carboxylate groups containing reaction products of isophoronediamine and acrylic acid are included.

12. Polyurethane dispersions according to claims 1 to 5, characterized in that a mixed hydrophilization of nonionic hydrophilic components c) in amounts of 4 to 15 wt .-% and anionic hydrophilic components c) in amounts of 0.5 to 6 wt .-% is included.

13. Polyurethane dispersions according to claims 1 to 5, characterized in that a non-ionic hydrophilic component c) is a monohydroxy-functional polyether having a molecular weight of 1000 to 2500 with a built-in propylene oxide content of 10 to 57% and a built-in ethylene oxide content of 90 to 43 wt .-% is included.

14. Polyurethane dispersions according to claims 1 to 5, characterized in that 0.1 to 1.0% by weight of hydrazine or an equivalent amount of hydrazine hydrate is contained as a chain extension component e)

15. Polyurethane dispersions according to claims 1 to 5, characterized in that the mathematically determined content of the solid of the polyurethane dispersions of -Si- (O) - structural units is less than 1.25% by weight.

16. Polyurethane dispersions according to claims 1 to 5, characterized in that the amount of isocyanate-reactive amino and / or hydroxyl groups of chain extenders e), blocking agents f) and mono-functional alkoxysilane g) 35 to 85 equivalent percent based on free Isocyanate groups of the prepolymer from a) to d).

17. Polyurethane dispersions according to claims 1 to 5, characterized in that blocking agents f) are present in amounts of 1) to 3.5% by weight.

18. Glass fiber size containing polyurethane dispersions according to claims 1 to 5 as an essential film-forming component.

19. Glass-fiber size containing polyurethane dispersions according to claims 1 to 5 as an essential film-forming component and blocked polyisocyanate crosslinking agents which may have hydrophilic groups.

20. A process for the preparation of special polyurethane dispersions with alkoxysilane end groups according to claims 1 to 5, characterized in that from at least one polyol a), at least one isocyanate component b), optionally with the use of hydrophilizing components c) or a component d) an isocyanate-functional prepolymer is first prepared, then some of the remaining isocyanate groups are reacted either in organic solution or after dispersing with a chain extension component e), optionally a hydrophilizing component c) and optionally a blocking agent f) and the remaining isocyanate groups are then reacted with an amino-functional alkoxysilane g) either before, during or after dispersing, and the solvent which may have been added before, during or after the prepolymer preparation is then removed by distillation, if appropriate.

21. A process for the preparation of special polyurethane dispersions having alkoxysilane end groups according to claims 1 to 5, characterized in that initially trifunctional or higher-functional polyisocyanates are reacted with such amounts of monofunctional alkoxysilanes, which results in a difunctional alkoxysilane-modified isocyanate component bg) which results in at least one polyol a) optionally a diisocyanate component b), at least one hydrophilizing component c) and optionally a component d) are converted into an isocyanate-functional prepolymer, then some of the remaining isocyanate groups are either organic

Solution or after dispersing with a chain extension component e), optionally with a hydrophilizing component c) and optionally a blocking agent f) and then the solvent optionally added before, during or after the prepolymer preparation is optionally removed by distillation.

22. Use of special polyurethane dispersions with alkoxysilane end groups according to claims 1 to 17 in or as sizes, in particular for glass fibers.

3. Use of special polyurethane dispersions with alkoxysilane end groups according to claims 1 to 17 in or as a coating and / or lacquer.