KR100543488B1 - Organosilane Oligomers - Google Patents

Abstract

The present invention relates to organic solvent soluble oligomers obtainable by condensing the same or different monomers of the formula (II). The oligomers are suitable for coating plastic materials, mineral and metallic support materials and glass.

<Formula II>

Wherein R ₁ is C ₁ -C ₆ alkyl or C ₆ -C ₁₄ aryl,

R ₂ is hydrogen, alkyl or aryl when b is 1, alkyl or aryl when b is 2 or 3,

R ₃ is alkyl or aryl,

m is 3 to 6,

q is 2 to 10,

b is 1, 2 or 3.

Organosilanes, oligomers, coatings.

Description

Organosilane Oligomers             

The present invention relates to organosilane oligomers suitable as coating compositions.

German Patent No. 196 03 241 and International Patent Publication No. 94/06807 disclose a number of cyclic organic silanes in which inorganic / organic hybrid systems can be prepared by sol / gel processes. The material can be used to coat the surface. The resulting coatings are characterized by elevated transparency, good solvent resistance and high wear resistance with good elasticity.

When coating porous substrates, such as porous inorganic particles or mineral surfaces (eg stone surfaces), the monomeric organic silanes penetrate deep into the material in order to protect the surface effectively and thus are not economical, for example multiple Should be applied as a coat. It is only with the above that a coating suitable for example as an anti-scratch coating is obtained.

The object of the present invention is to overcome the above disadvantages. However, the coating material to be developed for this purpose must be soluble in organic solvents so that it can be used at least.

This object is achieved with oligomers of certain cyclic organosilanes.

The present invention therefore provides an organic solvent soluble oligomer (I) obtainable by condensing the same or different monomers of the formula (II).

In the formula, m means 3 to 6, preferably 4,

q means 2 to 10, preferably 2,

b means 1, 2 or 3, preferably 1 or 2,

R ₁ means C ₁ -C ₆ alkyl or C ₆ -C ₁₄ aryl, preferably methyl or ethyl,

R ₂ means hydrogen, alkyl or aryl when b is 1 or alkyl or aryl when b is 2 or 3,

R ₃ means alkyl or aryl, preferably methyl.

Examples of compounds of formula (II) are as follows.

(II-1) cyclo- {OSiCH ₃ [(CH ₂ ) ₂ Si (OH) (CH ₃ ) ₂ ]} ₄ ,

(II-2) cyclo- {OSiCH ₃ [(CH ₂ ) ₂ Si (OCH ₃ ) (CH ₃ ) ₂ ]} ₄ ,

(II-3) cyclo- {OSiCH ₃ [(CH ₂ ) ₂ Si (OCH ₃ ) ₂ CH ₃ ]} ₄ ,

(II-4) cyclo- {OSiCH ₃ [(CH ₂ ) ₂ Si (OC ₂ H ₅ ) ₂ CH ₃ ]} ₄ ,

(II-5) cyclo- {OSiCH ₃ [(CH ₂ ) ₂ Si (OC ₂ H ₅ ) ₃ ]} ₄ .

Suitable organic solvents for the oligomers are, for example, mono and polyfunctional alcohols such as methanol, ethanol, n-butanol, ethylene glycol as well as mixtures of aromatic hydrocarbons and aliphatic ketones or esters.

Oligomers (I) may be prepared from monomers of formula (II) or may be prepared directly from starting materials for the preparation of monomers of formula (II), and starting materials that may be considered include halogen atoms, for example For example compounds of formula (II) containing chlorine, bromine or iodine atoms in place of the OR ₂ group. The oligomer (I) is preferably prepared using the corresponding chlorosilanes. The reaction proceeds in the presence of water and / or alcohol. The hydrogen chloride gas formed in the reaction is stripped or washed off, optionally in the presence of a base (eg NH ₃ ). If the resulting oligomeric mixture still contains Si-Cl groups, it can be worked up with another base, for example in the presence of water and / or alcohol.

Gacoalcolysis and hydrolysis of chlorosilanes are known in principle to those skilled in the art.

Surprisingly oligomer (I) is soluble in solvents and has a multifunctional reactor, but is not crosslinked during its preparation. For example, according to the method described in WO 94/06807 (sol / gel method), it is impossible to terminate the polymerization reaction in order to obtain a stable soluble oligomer (I) during storage. Hydrolysis and condensation are continued until an insoluble and insoluble gel is obtained.

The oligomers are not only suitable for coating particles, in particular particles with inorganic constituents, preferably pure inorganic particles, but also graffiti on mineral and metallic substrates or organic coatings (e.g. on buildings or automobiles) to improve mechanical strength. It is suitable for coating plastics as anti-coat and for hydrophobizing substrates such as stones or glass.

The oligomers are optionally used as (co) condensates with alkoxides, for example compounds of formula (III) and / or nanoparticles of formula (IV).

M ₁ (OR ₄ ) _y

In the above formula, M ₁ means Si, Sn, Ti, Zr, B or Al,

R ₄ means alkyl or aryl, preferably C ₁ -C ₄ alkyl,

y means 4 for Si, Sn, Ti, Zr, and 3 for B or Al.

Examples of alkoxides of formula (III) are as follows.

(III-1) Si (OC ₂ H ₅ ) ₄ ,

(III-2) B (OC ₂ H ₅ ) ₃ ,

(III-3) Al (OiC ₃ H ₇ ) ₃ ,

(III-4) Zr (OiC ₃ H ₇ ) ₄ .

Examples of nanoparticles (IV) are finely divided metal oxides or metal oxide hydroxides of the elements Si, Sn, In, Ti, Zr, B or Al, for example silica sol containing especially organic solvents. Its preferred average particle size, measured using ultracentrifugation, is 1 to 100 nm, preferably 1 to 50 nm, so it is called "nanoparticle".

The coating preferably contains 0.1 to 100% by weight oligomer (I), 0 to 70% by weight nanoparticles (IV), 0 to 99.9% by weight alkoxide (III) and 0 to 10% by weight of catalyst (V). The coating particularly preferably contains 20 to 80% by weight oligomer (I), 20 to 80% by weight alkoxide (III), 0 to 50% by weight nanoparticle (IV) and 0 to 5% by weight catalyst (V). .

Suitable catalysts (V) are organic and inorganic acids or bases such as HCO ₂ H, CH ₃ COOH, HCl, NH ₄ OH and alkali metal hydroxides as well as fluorine containing salts such as NaF or NH ₄ F have. The added metal alkoxide itself, such as Ti (OC ₂ H ₅ ) ₄ and Ti (OiC ₃ H ₇ ) ₄ , can be catalytically active. Metal soaps such as zinc octoate or dibutyltin laurate may also be used.

In a preferred embodiment the oligomer (I) is initially mixed with the alkoxide (III) and / or nanoparticle (IV), optionally in a solvent and optionally reacted with each other in the presence of a catalyst (V). It is particularly advantageous to react the reaction mixture with water initially, optionally in the presence of a catalyst, in order to increase the reactivity and reduce the loss of the low boiling high volatile starting material from the reaction mixture, resulting in a less reactive volatile condensation product. German Patent Publication No. 196 03 242 and International Patent Publication No. 94/06897 disclose details in the preparation of condensation products, optionally in the presence of alkoxides. For example, polyfunctional organic silanes may be stirred with alkoxides, solvents, water and catalysts and reacted for a period of time before the film or completed reaction (gelling) and also moldings may be obtained from this solution.

After a certain reaction time the coating solution is applied onto the material by a suitable process, for example brushing, spraying or dipping, the volatile components evaporate and the resulting coating is optionally postcured by heat.

<Example 1>

Preparation of 1,3,5,7-tetramethyl-1,3,5,7-tetra- (2- (dichloromethylsilyl) ethylene) cyclotetrasiloxane

229.3 g (0.667 mol) of 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, 125 g of xylene and 36 mg of platinum catalyst were stirred and heated to 60 ° C. Then 252.1 g (2.668 mol) of methyldichlorosilanes were added dropwise. An exothermic reaction occurred. After completion of the dropwise addition, the mixture was refluxed and stirred for another 2 hours. After cooling to room temperature the mixture was perfused with N ₂ , filter aid (diatomaceous earth) was added and the mixture was filtered. The product was used for another synthesis without further investigation.

<Example 2>                 

Preparation of condensation product of 1,3,5,7-tetramethyl-1,3,5,7-tetra- (2- (diethoxymethylsilyl) ethylene) cyclotetrasiloxane

600 g of the solution prepared according to Example 1 of 1,3,5,7-tetramethyl-1,3,5,7-tetra (2- (dichloromethylsilyl) ethylene) cyclotetrasiloxane was initially introduced into the vessel It was. 500 g of ethanol were introduced below the liquid surface at a pressure of about 500 millibars. The mixture was then distilled at 10 millibar pressure and 60 ° C. and perfused with N ₂ . Another 250 g of ethanol were then added and the mixture was distilled to 10 millibar pressure and 100 ° C. and then perfused with N ₂ . Ammonia was then introduced through the gas inlet line until saturated and the mixture was stirred for 4 hours. Excess ammonia was then removed and ammonia chloride was removed by filtration. The filtrate was neutralized with Na ₂ CO ₃ , combined with filter aid (diatomaceous earth) and heated to a temperature of 130 ° C. and a pressure of 10 millibars.

The product was obtained as a clear liquid having a viscosity of 80 mPa · s, a density of 1.00 g / ml and a residual hydrolyzable chlorine content of 7 ppm. The molecular weight distribution was determined by high speed gel permeation chromatography (SGPC) using dichloromethane as solvent by IR and RI detection. The condensation product of 1,3,5,7-tetramethyl-1,3,5,7-tetra- (2- (diethoxymethylsilyl) ethylene) cyclotetrasiloxane has a number average molecular weight (M _n ) 1350 g / mol And a continuous molecular weight distribution having a weight average molecular weight of 3355 g / mol.

Claims (11)

An organic solvent soluble oligomer obtainable by condensing the same or different monomers of the formula (II). <Formula II>

Wherein R ₁ means C ₁ -C ₆ alkyl or C ₆ -C ₁₄ aryl, R ₂ means hydrogen, alkyl or aryl when b is 1, alkyl or aryl when b is 2 or 3, R ₃ means alkyl or aryl, m means 3 to 6, q means 2 to 10, b means 1, 2 or 3. The compound of claim 1, wherein R ₁ means methyl or ethyl, R ₂ means hydrogen, methyl or ethyl when b is 1, methyl or ethyl when b is 2, R ₃ means methyl, m means 4, q means 2, b means 1 or 2, organic solvent soluble oligomer. The organic solvent soluble oligomer of claim 1, which is obtained by condensing the same or different monomers of formula (II) having a chlorine atom in place of OR _{2 in} the presence of water and / or alcohol. A coating composition for coating plastic, mineral and metallic substrates and glass comprising the oligomers of claim 1. The coating composition of claim 4 wherein the oligomer is a cocondensate with an alkoxide of the formula: M ₁ (OR ₄ ) _y In the above formula, M ₁ means Si, Sn, Ti, Zr, B or Al, R ₄ means alkyl or aryl, y means 4 for Si, Sn, Ti, Zr, and 3 for B or Al. The coating composition of claim 4 or 5, wherein the oligomer is a cocondensate with nanoparticles. The coating composition of claim 6, wherein the coating contains from 0.1 to less than 100% by weight of oligomer, from 0 to 70% by weight of nanoparticles, from 0 to 99.9% by weight of alkoxide and from 0 to 10% by weight of catalyst. The coating composition of claim 6, wherein the coating contains 20 to 80 weight percent oligomer, 20 to 80 weight percent alkoxide and greater than 0 to 50 weight percent nanoparticles and 0 to 5 weight percent catalyst. The coating composition according to claim 7 or 8, which contains an organic or inorganic acid or base as a catalyst. 6. The coating composition of claim 5, wherein the coating contains from 0.1 to less than 100 weight percent oligomer, from 0 to 70 weight percent nanoparticles, from 0 to 99.9 weight percent alkoxide and from 0 to 10 weight percent catalyst. The coating composition according to claim 5, wherein the coating contains 20 to 80% by weight oligomer, 20 to 80% by weight alkoxide and 0 to 50% by weight nanoparticles and 0 to 5% by weight catalyst.