DE3220393C2 - Guanidinium (organo) siliconates or silicates, process for their production and use for impregnating mineral building materials - Google Patents

Abstract

Guanidinium (organo) siliconates or silicates of the general formula (formula 1) where R ↑ 1 is the same or different within the compound, an alkyl radical with 1 to 4 carbon atoms, an alkenyl radical with 2 to 4 carbon atoms or a phenyl radical, R ↑ 2 is the same or different within the compound, denotes a hydrogen radical, an alkyl radical with 1 to 4 carbon atoms, an alkenyl radical with 3 to 4 carbon atoms, a = 0 to <3.9, b = 0.1 to 4 and x = 0 to 1.25, but where x> 0 when R ↑ 2 is a hydrogen radical, and where Σ a + b + x ≦ 4. The compounds are prepared by reacting guanidinium hydroxide with compounds of the general formula (formula 2) where R ↑ 1, R ↑ 2 and x have the meaning given above and c> 0 to 4, and optionally reacting the product with finely divided SiO ↓ Reacts 2 or optionally partially hydrolyzed silicic acid ester. The compounds are valuable agents for the waterproofing impregnation of mineral building materials.

Description

whereby

R ^{1 is} an alkyl radical having 1 to 3 carbon atoms or a phenyl radical

R ² denotes an alkyl radical with 1 to 3 carbon atoms,

a = 0 to <35,

b = 0.1 to 4 and

χ = 0 to 1.25, and where £ a + b + xS4 .

2. Process for the preparation of compounds according to claim 1, characterized in that one Guanidinium hydroxide with compounds of the general formula

(OR ² ),
R ¹ - Si - O ₄ -, - _r

whereby

R ¹ , R ² and χ have the meaning given above and
c> 0 to 4,

in water and / or in a water-miscible organic solvent in a temperature range lets react from 0 to 80 ° C and optionally then the process product with Feinteiügem S1O2 or optionally partially hydrolyzed silicic acid ester.

3. Use of the compounds according to claim 1 for the waterproofing impregnation of mineral Building materials.

It is known that alkali methyl siliconates in the form of their aqueous solutions for impregnating mineral Use building materials. A process for the preparation of particularly suitable alkali methyl siliconates is found in the DE-PS 11 76 137 described. In this process, monomethylsilicon trichloride is used with alkali in such a way that the methyl silicic acid is removed from the alkali methyl siliconate solutions containing alkali Addition of acid or acid-releasing compounds until a pH value of about 4 is reached precipitates below 60 ° C and the separated methylsilicic acid dissolves in equimolar amounts and optionally freed the solution obtained from the water.

The process products are used for the impregnation of mineral building materials, such. B. for facade or roof tile impregnation, excellently suited. They can also be used in powder form and z. B. in this form Mortar can be added. A particular advantage of the alkali metal siliconates produced by this process is their low content of alkali chlorides. This as low as possible content is desirable in order to prevent efflorescence Avoid table salt on the surface of the impregnated building materials.

However, there is also in the method of the aforementioned DE-PS 11 76! 37 the problem that the precipitated methylsilicic acid is not stable in storage and must therefore be used immediately. Also contains Even after this process, the precipitated methyl silicic acid significant amounts of water, so that even with the Production of a solution of only 30% from the resulting solution of sodium methylsiliconate, water must be removed by distillation.

The European patent application 00 15 366 is based on the task of finding a method which alkali metal organosiliconate solutions are obtained free of alkali metal grids, in which, if possible, one Filtration stage can be avoided and which allows solutions of any concentration to be prepared. The subject of European patent application 00 15 366 is therefore a process for the preparation of aqueous Solutions of alkali organosiliconates, the organo radical of which is an alkyl radical with 1 to 3 carbon atoms Vinyl radical and / or a phenyl radical, and the alkali radical of which is a sodium or potassium ion. with the mark, that one organoalkoxypolysiloxanes of the general formula

(OR \ R ^! —Si— O ₄ - (

worm

R ^{1 is} an alkyl radical with 1 to 3 carbon atoms, a vinyl radical and / or phenyl radical

R ^{2 is} an alkyl radical with 1 to 4 carbon atoms,

a is a number £ 2 and

χ Ibis is 1.25

with aqueous solutions of NaOH or KOH with a concentration of 0.7 to 0.9 [mol-100 g- '] at temperatures S 80 ^° C., if necessary, the liberated alcohol R ² OH is distilled off and / or the solution of the reaction product is made up with water sets the desired concentration ... "

However, the alkali metal siliconates of the prior art, regardless of the manner in which they are prepared, have the disadvantage that, when they are formed with the formation of e.g. B. Organosilicic acid can be precipitated on the masonry. Form alkali carbonates, which can lead to efflorescence. Another disadvantage of the alkali metal siliconates is their poor solubility in organic solvents. In practice, they can only be used from aqueous solutions. It is therefore only possible, e.g. Treat as masonry only once since £ - is at least hydrophobic after the treatment at the surface and therefore can not nenetrieren an aqueous Siücor.atlösung, so that multiple treatment of masonry with aqueous solutions meets with great difficulties. ,

The invention is therefore based on the object. To find siliconates that do not have these disadvantages and which can also be produced in the simplest possible way.

It has surprisingly been found that compounds of the general formula

10

15th

20th

25th

(OR ² ).

R ¹ —Si—

⁹ NH ₂

Il
H ₂ NC-NH ₂

(Q 30

J b

have the desired properties. In this formula, R ^{1 is} an alkyl radical having 1 to 3 carbon atoms or a phenyl radical. Within the polymeric molecule, R ^{1 can have} various of these meanings given

R2 has the meaning of an alkyl radical with 1 to 3 carbon atoms. Within the polymeric molecule, R ^{2 can} also have different meanings. The index a has a value from 0 to <3.9 and indicates the content of OR ² groups. The index b has a value from 0.1 to 4. χ has a value from 0 to \, Λ and indicates the number of hydrocarbon groups bonded to silicon. The sum a + b + χ is equal to or smaller

than 4

Particularly preferred are compounds in which R ^{1 is} a methyl and / or phenyl radical, R ^{2 is} a methyl and / or ethyl radical, a = 0.5 to 2, b = 0.5 to 2, χ = 0.5 to 1.15 and 2 is a + b + χ S 4.

These guanidinium salts are in water or polar solvents, such as. B. alcohol, especially methanol or ethanol, or soluble in aqueous mixtures of these alcohols.

The compounds of the formula I can be prepared according to the invention in a simple manner by Guanidinium hydroxide with compounds of the general formula

(OR ² ),

R ¹ —Si—

35

40

45

50

whereby

R '<, R ² and χ have the meaning given above and
c> 0 to 4,

in water and / or in a water-miscible organic solvent in a temperature range from 0 to 80 ⁵ C and optionally then reacting the process product with finely divided SiO ₂ or optionally partially hydrolyzed silicic acid ester.

Since it was known from European patent application 00 15 366 that the reaction of the alkoxypolysiloxanes with the aqueous solutions of NaOH or KOH must be carried out at temperatures -80.degree. the person skilled in the art had to assume that the claimed guanidinium salts could not be produced, since at temperatures above 80 ^° C. guanidinium compounds already decompose noticeably. It was all the more surprising to find that the reaction of the guanidinium hydroxide with the organosilicon compounds of the formula II takes place even at significantly lower temperatures, namely in a temperature range of 0

55

60

65

to 80 ⁰ C, insesondere 20 to 50 ⁰ C, can be carried out practically quantitative. In this temperature range, however, decomposition of the guanidinium hydroxide is not yet to be feared, especially not if a reaction temperature of: £ 70 ^° C. is chosen

As water-miscible solvents are in particular lower alcohols such. B. methanol or Ethanol.

The process according to the invention can, as already stated, be continued by further reacting the process product initially obtained with finely divided SiO ₂ or optionally partially hydrolyzed silicic acid ester. The reaction runs z. B. in the following sub-steps:

10

15th

20th

(OR ² ), ⁹ NH ₂

^ Si-O ₄ -XC + b H ₂ NC-NH ₂ ⁹ OH

(OR ² ), -Si-O O

Il

H ₂ NC-NH ₂

+ b R ² OH

.J t

(OR \

Si

(0%

^S NH ₂

Il

H ₂ NC-NH ₂

+ SiO ₂

(OR ² ) ,, «

2 Si O ₄ -x / 2-a / 2-6 / 2

(O% ₂

®NH ₂

II H ₂ NC-NH ₂

This makes it possible to set the R ¹ : Si ratio in the desired manner.

The compounds according to the invention are particularly suitable according to claim 3 above for the hydrophobic impregnation of mineral building materials. When exposed to carbon dioxide there are no carbonates causing efflorescence; rather, the guanidine carbonate decomposes iri Urea and ammonia. It is also possible to use the Guanidiniumorganosiüconate and silicates in the form of organic solutions, e.g. B. in lower alcohols, and thus a better penetration of the to effect mineral raw materials.

The subject matter of the invention is explained in more detail using the following examples.

40

45

example 1

24.5 g (0.3 mol) of a methyl silicone resin, described by the average formula, are added to a solution of 23.1 g (03 mol) of guanidinium hydroxide and 33.1 ml of water with vigorous stirring at 40 to 50 ^{° C.}

CH ₃ SiO ₁₃ (OC ₂ H ₅ ) ", ₄

added dropwise over 2 h. After stirring for 5 h at 40 ° C., the initially cloudy reaction mixture turns into a clear, 51.1% strength by weight guanidinium methylsiliconate solution over. The elemental analysis of the evaporation of the volatile constituents at 50 ° C / 15 Torr result in:

C 17.6%; H 6.9%; N 26.6%; Si 17.6%. This results in the following formula:

55

60

O _0-915 NH ₂

CH ₃ -Si-O ⁹ H ₂ N = C

(OC ₂ Hs) ₀ ,,, NH ₂

with the theoretical values: C 17.73%; H 7.53%; N 26.50%; Si 17.71%.

H ₂ O

Example 2

The procedure described in Example I is repeated with the exception that in place of the methyl silicone resin 49.0 g (0.3 mole) of a phenyl silicone resin described by the average formula

be used. After stirring for 6 hours at 40 ° C., a clear one forms. 63.2% strength by weight solution of a guanidinium phenyl siliconate. The elemental analysis of the dry substance (dried at 50 "C / 15 Torr) shows:

C 39.3%; H 6.1%; N 19.5%; Si 12.4%. This results in the following formula:

NH ₂

<TJ> - Si - Ο ^θ H ₂ N = C ■ H ₂ O

with the theoretical values:

C 39.0%; H 6.08%; N 19.5%; Si 13.0%.

20th

25th

Example 3

To a solution of 23.1 g (0.3 mol) of guanidinium hydroxide and 25 g of ethanol, a solution of 49.2 g (0.3 mol) of n-propyltrimethoxysilane and 28.2 g of ethanol is added with vigorous stirring at 40 ° for 1 hour to 5O ⁰ C added dropwise. After stirring at 40 ° C. for 8 hours, 12.6 ml of water are added dropwise. It forms: a clear, 39.0% strength by weight solution of a guanidinium n-propylsiliconate. The elemental analysis of the dry matter shows:

C 26.2%; N 22.7%; Si 15.1%.

This results in the following formula:

C ₃ H ₇ -Si-O ⁹ H ₂ N = C '

i O

with the theoretical values:

C 26.5%; N 23.2%; Si 15.5%.

NH,

NH ₂

H ₂ O

Example 4

O ,, 05

(CH ₃ -VsSi -

⁹ NH ₂ H ₂ NC-NH ₂

40 45

A solution of 24.5 g of the methyl silicone resin described in Example 1 in 20 g of ethanol is added to a solution of 23.1 g (03 mol) of guanidinium hydroxide and 13.5 g of ethanol over a period of 1 hour with vigorous stirring at 40 °. is 50 ⁰ C added dropwise. After stirring for 8 h, a cloudy, viscous liquid forms which, by adding 26.8 g of ethanol, forms a clear, ethanolic, 40.0% strength by weight solution of a guanidinium methylsiliconate.

B e i s ρ i e 1 5

The process according to Example 4 is repeated with the change that after the addition of the methyl silicone resin the guanidine solution is stirred for 2 h. 45.6 g of ethyl silicate 40 (40% S1O2) are then added over a period of 6 hours at 40.degree stirred and described with 68.7 g of ethanol to form a 40% strength by weight solution of a guanidinium methyl siliconate by the average formula

65

diluted.

Example 6

24.4 g (0.3 mol) of one are added to a solution of 28.5 g (0.3 mol) of guanidine (62.1% strength by weight ethanolic solution) and 27.4 g of water with vigorous stirring at 40 to 50 ^{° C.} Methyl silicone resin described by 5 the average formula

(OC ₂ Hs) _0-4

added dropwise and ^{stirred at 40 0} C for a further 8 h. A clear, 51.4% strength by weight solution of a guanidinium methylsiliconate is described by the average formula

(OC ₂ H ₅ V ₁₂
(CH ₃ -) ,. _O7 Si - O ^e

⁹ NH ₂
H ₂ NC-NH ₂

won. The elemental analysis of the dry matter shows:
C 17.7%: H 7.5%; N 26.2%; Si 16.9%.

This results in the following formula:

(OC ₂ H ₅ V ₁₂ NH ₂

(CH ₃ -) _U37 Si-O ^e H ₂ N = CH ₂ O

O _M71 NH ₂

with the theoretical values:

C 17.94%; H 7.62%; N 26.47%; Si 17.7%.

Example 7

To 23.2 g (0.0875 mol) of the 51.1% strength by weight aqueous product solution of guanidinium methylsiliconate according to 40 Example 1, 1.66 g (0.0125 mol) of dimethyldiisopropoxysilane are added, and the reaction mixture is allowed to react for 24 hours vigorously stirred at room temperature. A clear solution of a guanidinium methyl siliconate forms. described by the average formula

(CH ₃ -) _U25 Si - Ο ^θ

0.937

⁹ NH ₂
H ₂ NC-NH ₂

Example 8

9.24 g of guanidinium hydroxide in 31.8 g of ethanol are added at 50 ° C. with vigorous stirring to a mixture of 24.5 g (0.3 mol) of the methyl silicone resin described in Example 1 and 62.5 g (03 mol) of tetraethoxysilane added dropwise, and it is ^{stirred at 50 0} C for 6 h. There is a guanidinium methyl siliconate described by the average formula

(OC ₂ H ₅ ),

o ₍

0.65

⁹ NH ₂
H ₂ NC-NH ₂

0.2

65 won.

Claims (1)

Patent claims:
1. Guanidinium (organo) siliconates or silicates of the general formula © NH ₂ Il
H ₂ N-C-NH ₂ R ¹ - Si - O _{4 - x}