MXPA99010760A

MXPA99010760A - Organosilane oligomers

Info

Publication number: MXPA99010760A
Application number: MXPA/A/1999/010760A
Authority: MX
Inventors: Mechtel Markus; Mager Michael
Original assignee: Bayer Aktiengesellschaft
Priority date: 1997-05-23
Filing date: 1999-11-22
Publication date: 2000-09-04

Abstract

The invention relates to oligomers soluble in organic solvents, which oligomers can be obtained by condensation of the same or different monomers of formula (II), where R1 is a C1-C6 alkyl or a C6-C14 aryl;R2 is hydrogen, alkyl or aryl if b equals 1, or alkyl or aryl if b equals 2 or 3;R3 is alkyl or aryl;m is between 3 and 6;q is between 2 and 10;and b is 1, 2, or 3. Said oligomers are suitable for coating plastic materials, mineral and metallic support materials and glass.

Description

OLIGOMEROS DE ORGANOSILANO Field of the invention: The invention relates to organosilane oligomers which are suitable as coatings.

In DE 196 03 241 and WO 94/06807 numerous cyclic organosilanes are disclosed, from which inorganic-organic hybrid materials can be produced by a sol-gel process. These materials can be used for surface coating. The coatings obtained are characterized by high transparency, good resistance to solvents and a high resistance to mechanical wear with excellent elasticity.

During the coating of porous substrates, for example, porous inorganic particles or mineral surfaces (for example, stone surfaces) monomeric organosilanes penetrate much into the material and therefore must be applied in large quantities, which is not profitable, for example applying several layers to be able to effectively cover the surface. This is when the coatings are, for example, suitable as anti-graffiti coatings.

It was the object of the invention to avoid all these mconve- REF. : 31849 nientes. The coating materials to be developed to solve this task should, however, be soluble in organic solvents so that they can be used.

The task was solved with oligomers of certain cyclic organosilanes.

Therefore, oligomers (I) soluble in organic solvents, which can be obtained by condensation of the same or of different monomers of formula II, are the object of the invention. in which m is 3 to 6, preferably 4, q is 2 to 10, preferably 2, b is 1, 2 or 3, preferably 1 or 2, R, is C 1 -C 6 alkyl or C 6 -C 14 aryl, preferably methyl or ethyl, R2 is hydrogen, alkyl or aryl when b is 1, or alkyl or aryl when b is 2 or 3 and R3 is alkyl or aryl, preferably methyl.

Examples of compounds of formula (II) are: (II-l) cycle-. { 0SiCH3 [(CH2) 2Si (OH) (CH3) 2]} 4, (II-2) cycle-. { OSiCHj [(CH2) 2Si (OCH3) (CH3) 2]} 4, (II-3) cycle-. { OSCH 3 [(CH2) 2 Si (OCH3) 2CH3]} 4, (II-4) cycle-. { 0SiCH3 [(CH2) 2Si (OC2H5) 2CH3]} 4, (II -5) cycle-. { OSÍCH3 [(CH2) 2Si (OC2Hs) 3]} Four.

Organic solvents suitable 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 ketones or aliphatic esters.

The oligomers (I) can be prepared directly from monomers of formula (II) or from the starting materials for the production of the monomers of formula (II), where said compounds of formula (II) are considered as starting products. ), which instead of the group 0R2, contain a halogen atom, for example, a chlorine, bromine or iodine atom. Preferably for the production of the oligomers (I) the corresponding chlorosilanes are used. The reaction is carried out in the presence of water and / or alcohol. The hydrochloric gas produced is removed or washed, optionally in the presence of a base (for example, NH3). In the case that the mixture of oligomers obtained still contains Si-Cl groups, it can subsequently be treated, for example, with another base in the presence of water and / or alcohols.

The alcoholysis and hydrolysis of chlorosilanes is known in general terms by the specialist.

Surprisingly, the oligomers I are soluble in solvents and cross-link well during their production although they have multifunctional reactive groups. According to the process described, for example, in WO 94/06807 (sol-gel process), it is not possible to stop the polymerization process in order to obtain stable and stable oligomers (I) during storage. Hydrolysis and condensation continue until an immiscible and insoluble gel forms.

These oligomers are suitable for the coating of particles, especially particles with an inorganic content, preferably purely inorganic particles, also for plastics coating in order to improve the mechanical resistance, as an anti-graffiti coating on mineral and metallic substrates or organic coatings (for example , in buildings or vehicles) and for the hydrophobicization of substrates, for example, stone or glass.

The application of these oligomers is optionally carried out by (co) -condensation with alkoxides, for example, those of formula III and / or nanoparticles (IV), M, (0R4) v (nor: in which M is Si, Sn, Ti, Zr, B or Al, R 4 is alkyl or aryl, preferably C, -C 4 alkyl, and in the case of Si, Sn, Ti, Zr is 4 and in the case of B or Al is 3.

Examples of alkoxide of formula III are (III-1) Si (OC 2 H 5) 4 (III-2) B (OC2H5) 3 (III-3) Al (0-i-C3H7) 3 (III-4) Zr (0-i-C3H7) 4.

Examples of nanoparticles (IV) are metal oxides or hydroxides of fine-particle metal oxides of the elements Si, Sn, In, Ti, Zr, B or Al, for example, silica sol, which contain especially organic solvents. The preferred average particle sizes are in the range of 1 to 100 nm, preferably 1 to 50 nm, henceforth referred to as "nanoparticles".

The coatings preferably contain from 0.1 to 100% by weight of oligomers (I), from 0 to 70% by weight of nanoparticles (IV), from 0 to 99.9% of alkoxide (III) and from 0 to 10% by weight of catalyst (V). Especially preferred coatings contain from 20 to 80% by weight of oligomers (I), from 20 to 80% by weight of alkoxide (III), from 0 to 50% by weight of nanoparticles (IV) and from 0 to 50% by weight. catalyst weight (V).

Suitable catalysts (V) are organic and inorganic acids or bases, for example, HC02H, CH3COOH, HCl, NH4OH and alkali hydroxides, as well as salts containing F, such as NaF or NH4F. Also the added metal alkoxides can themselves be catalytically active, such as Ti (OC2H5) 4 and Ti (Oi-C3H7) 4. Likewise, saponified metals, such as zinc octoate or dibutyltin laureate can also be used.

In a preferred embodiment, the oligomers (I) are first mixed, optionally in a solvent, with the alkoxides (III) and / or the nanoparticles (IV) and optionally in the presence of a catalyst (V) and are allowed to react . In order to increase the reactivity and decrease the application of very volatile and low boiling starting materials, such as tetraethyl orthosilicate, it is very convenient to initially react the starting materials with water, possibly in the presence of a catalyst, forming reactive condensates. and that are less volatile. In DE-OS 196 03 242 and WO 94/06897 more data can be found for the preparation of condensates, optionally in the presence of alkoxides. For example, to the polyfunctional organosilanes with the alkoxides a solvent, water and a catalyst can be added to them at the same time as they are stirred and allowed to react for a determined time, and films can also be obtained from these solutions or, after the complete reaction (gelation), molded bodies.

After a given reaction time, this coating solution is applied to the materials by a suitable method, for example by spreading, spraying or impregnation, the volatile components are evaporated and the coating thus obtained is optionally hardened afterwards thermally.

Eg emplos Example 1; Preparation of 1, 3, 5, 7-tetramethyl-l, 3, 5, 7-tetra- (2-dichloromethyl-silyl) ethylene) -cyclotetrasiloxane 229.3 g (0.667 mol) of 1,3,5,7-tetramethyl-l, 3,5,7-tetravinyl-cyclotetrasiloxane, 125 g of xylene and 36 mg of platinum catalyst were heated to 60 ° C with stirring. and they stirred. Then 252.1 g (2,668 mol) of methyldichlorosilane were added dropwise. An exothermic reaction occurred. After the end of the dropwise addition, another 2 hours were stirred at reflux. After cooling to room temperature, a stream of N2 was passed, a medium was added to filter (diatomaceous earth) and filtered. The product was used without further tests for other syntheses.

Example 2: Preparation of the condensation product of 1,3,5,7-tetramethyl-l, 3,5,7-tetra- (2- (diethoxymethylsilyl) ethylene) -cyclotetrasiloxane 600 g of the solution prepared according to Example 1 were prepared from 1,3,5,7-tetramethyl-1,3,5,7-tetra- (2-dichloro-methylsilyl) ethylene) -cyclotetrasiloxane. They were introduced at a pressure of approximately 500 mbar and 500 g of ethanol below the liquid surface. It was then distilled to a pressure of 10 mbar and a temperature of 60 ° C and a current of N2 was passed through. Then 250 g of ethanol was added and distilled to a pressure of 10 mbar and a temperature of 100 ° C and a stream of N2 was passed through. Ammonia was introduced through a gas pipe to saturation and stirred for 4 hours. The excess ammonia was then removed and the ammonium chloride was filtered. The filtrate was neutralized with Na 2 CO 3, mixed with a filter medium (diatomaceous earth) and heated to 130 ° C under a pressure of 10 mbar.

The product appeared as a clear liquid with a viscosity of 80 mPa · s, a density of 1.00 g / ml and a residual amount of hydrolyzable chlorine of 7 ppm. The distribution of the molar mass was calculated by means of rapid gel filtration chromatography (SGPC) with dichloromethane as solvent and IR and Rl detector. The condensation product of 1,3,5,7-tetramethyl-1,3,5,7-tetra- (2- (diethoxymethylsilyl) -ethylene) -cyclotetrasiloxane appeared as a continuous partition of the molar mass with an average number (Mn) of 1. 350 g / mol and an average weight of 3,355 g / mol. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects or products to which it refers.

Claims

REIVINDI &ATIONS Having described the invention as above, property is claimed as contained in the following Oligomers soluble in organic solvents, which can be obtained by condensation of the same or different monomers of formula (ID characterized because; R, is C ^ Cf alkyl, or C6-C14 aryl, R-, is hydrogen, alkyl or aryl when b is 1, or alkyl or aryl when b is 2 or 3 and R, is alkyl or aryl, m is 3 a 6, q is 2 to 10, and b is 1, 2 or 3. Oligomers soluble in inorganic solvents according to claim 1, characterized in that; Rj is methyl or ethyl, R2 is hydrogen, methyl or ethyl, when b is 1, or methyl or ethyl when b is 2 and R3 is methyl, m is 4, q is 2 and b is 1 or 2. Oligomers soluble in organic solvents according to claim 1, uat < --- ü-ait-? It is also possible to use the same or different monomers of formula II, in which instead of OR 2 there is a chlorine atom, in the presence of water and / or alcohols. Use of the oligomers according to claim 1 for the coating of plastics, mineral and metallic substrates and glass. Use according to claim 4 by co-condensation of oligomers with alkoxides of formula M, (OR4) v where M is Si ", Sn, Ti, Zr, B or Al, R is alkyl or aryl, and in the case of Si, Sn, Ti, Zr is 4 and in the case of B or Al is 3. Use according to claims 4 and 5 in co-condensation with nanoparticles. Use according to claims 5 and 6, characterized in that the coatings contain from 0.1 to 100% by weight of oligomers, 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. Use according to claims 5 and 6, characterized in that the coatings contain from 20 to 80% by weight of oligomer, from 20 to 80% by weight of alkoxide, from 0 to 50% by weight of nanoparticles and from 0 to 5% by weight of catalyst. Use according to claims 7 and 8, characterized in that organic or inorganic acids or bases are used as a catalyst.