DE3916259A1 - Acid- and alkali-resistant binders and final mortars - comprise hydraulic binder-aggregate mixt. and di- or poly-isocyanate with aq. suspension of alkali metal silicate - Google Patents

Abstract

(1) Acid- and alkali-resistant binders and/or final mortars (I) comprise (a) a hydraulic binder with the usual 30-70 wt.% hard additives and (b) a mixt. of aliphatic and/or aromatic di- and/or poly-isocyanates (II) and an aq. suspension of alkali metal silicate (III) in the ratio 10-65 wt.% (II) to 35-10 wt.% SiO2 in (III). (2) A process is claimed for the prodn. of (I), in which the ratio (a):(b) is adjusted so that the whole of the water liberated in the chemical reaction of component (b) is chemically and physically bound by the binder in (a). USE/ADVANTAGE - (I) are useful for the prodn. of building components subject to partic. high chemical and physical stress, and for lining and renovation of such parts made of cement or with hydraulic binders (claimed). The invention enables, e.g. the renovation and lining of underground concrete channels to increase their resistance to acid and alkali, and also raise their temp. resistance to 1300 deg.C.

Description

The present invention relates to an acid-resistant and alkaline solution resistant binder and / or ready-mixed mortar and a ver drive to manufacture them and their use.

From DE-PS 16 69 181 is a process for the preparation of Binders based on alkali metal silicate suspensions known, this with certain triglycidyl isocyanu advise, water-soluble amines and optionally fillers and pigments mixed.

With these binders, paints, i.e. Thin coating are produced that lead to water-insoluble, wit harden resistant and elastic films. The chemical resistance of the paint or thinner obtained coatings, especially against acids and / or alkalis however not sufficient.

In the prior art, other coating materials and Mortar known, among other things, by mixing  Epoxy resin emulsions and hydraulic binders will. DE-OS 32 22 531 relates to epoxy resin diammonium salt emulsions based on a liquid epoxy resin, a latent hardener and an emulsifier. EP-A 02 07 473 relates to a method for producing a building material mixture from a reaction resin, a hardener, cement, a coarse and finer proportions containing aggregate and water. To Production of a storage-stable dry premix either initially the coarser portions of at least one Partial amount of the supplement submitted and with the liquid resin or mixed with the liquid hardener so that droplets or Films of the resin or hardener on the surfaces of the coarse can adhere granular aggregate adhesive. As a reaction resin an epoxy resin is used in particular.

DE-PS 28 40 874 relates to the use of a binder mixture of hydraulic hardener, epoxy resins, a hardener, Water and optionally reactive diluents, pigments and / or other common tools as a repair compound for renovation of defective reinforced concrete parts without the use of corrosion protective primer.

However, all of the aforementioned publications have in common that only limited chemical resistance point.

Pure organic resin systems, such as in "Ullmann’s Encyclopedia of Technical Chemistry", 4th edition, Volume 14, page 265 ff under the keyword "acid putty" are described in the event that they are used as acid or lye protection are designed, a satisfactory contradiction Resistance to these chemicals, they are however extremely difficult to apply in practice. Farther have these material properties that are strong  deviate from the surface to be coated. So is in the Rule of the modulus of elasticity and the coefficient of elongation the resin putty is different from that of the substrate, which Shear stresses result in damage.

Furthermore, from "Ullmann’s Encyclopedia of Technical Chemistry "(loc. Cit.) The use of water glasses as Acid putty known. The hardening of this water glass-bound Putty is made using various additives such as Silicofluoride, formamide or certain aluminum phosphates reached.

The object of the present invention was acid solid and alkali-resistant binders and / or ready-mixed mortar to provide the technical characteristics of the come as close as possible to the surface to be coated, immediately but also high demands on chemical resistance against acids and alkalis, as is particularly the case with the renovation of underground concrete channels is required.

In the course of the extensive investigations of the present Invention has been found to mix certain Isocyanates with alkali metal silicates and optionally acid esters on the one hand when using hydraulic binders and usual surcharges on the other hand as a further component acid-resistant and alkali-resistant binders and / or finished mortar result from the reaction of isocyanate and alkali Metal silicate carbon dioxide is formed, water is removed at the same time will split and the split water for hydration of the hydraulic binder is available, and thus the matrix system solidifies into a ceramic-like mass.

Here, acid-proof and alkali-resistant binders and / or ready mortar that meet the requirements in both  in terms of concrete technology as well as with regard to the chemical resistance is sufficient.

The above object is achieved in particular by acid solid and alkali-resistant binders and / or ready-mixed mortar out

• a) a hydraulic binder with usual hard aggregates of 30 to 70 wt .-%, based on the hydraulic binder medium,
  marked by
• b) a mixture of aliphatic and / or aromatic diiso cyanates and / or polyisocyanates and aqueous alkali metal silicate suspension in a ratio of 10 to 65 wt .-% of the isocyanate component to 35 to 10 wt .-% of the SiO ₂ content of the alkali metal silicate suspension.

Preferably contain the acid-resistant and alkali-resistant Binder as component (b) is a mixture of isocyanates and aqueous alkali metal silicate suspension in a ratio of 15 to 65 wt .-% of the isocyanate component to 28 to 14 wt .-% of SiO₂ content of the alkali metal silicate suspension.

In principle, all common types of cement can be used in the context of the invention, such as Portland cement, blast furnace cement, Eisenportland cement, road cement, HS cement, alumina melt cement, but also lime-rich pozzolans and pure lime and / or mixtures thereof. As a preferred hydraulic binding agent in the context of the invention, HS cements, Portland cements with a C ₂ S content of 62% and their mixing with alumina cement are used to control the reaction. The reaction of the substances of component b), ie the alkali metal silicate suspension with the organic esters and, in particular, additionally with silicone esters, results in colloidal SiO _{2 in} addition to water / R-OH. The reaction of the hydraulic binders with the absorbed water produces Ca (OH) ₂ , which according to (1) reacts to form calcil (CaSiO ₃ ), a particularly dense and solid material

Ca (OH) ₂ + n (SiO ₂₎ · x n = x + _CaSiO3 H ₂ O.

The hydraulic binder is thus removed from the reaction its stoichiometrically required amount of water.

One of ordinary skill in the art is a great one Number of hard aggregates known, usually in hydrau Chemical binders are used. In the sense of before lying invention are basalt, quartz, granite, corundum or their mixtures are particularly preferred as supplements, since these Materials have an extremely high resistance to acids and / or alkalis.

As diisocyanates are usually aliphatic or aromatic diioscyanates used, the selection of which later use depends. The aromatic diiso cyanates usually come from the group Toluene diioscyanate, 1,4-phenylene diisocyanate, 1,3-phenylene diisocyanate, 4,4'-dibenzyl diisocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 4,4'-di phenyldimethylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate and 1,5-naphthylene diisocyanate. Aliphatic diisocyanates usually come from the group of isophorone diisocyanate, 4,4'-methylenebis (cyclohexyl isocyanate), tetramethylene 1,4-diisocyanate, hexamethylene-1,6-diisocyanate and cyclo hexane-1,4-diisocyanate.

In a preferred embodiment, polyisocyanates used, namely on the basis of methylene diphenyl diisocyanate (MDI).  

The aqueous alkali metal silicate suspensions to be used according to the invention preferably have SiO ₂ contents of 20 to 45 ° B ', the ratio of alkali metal oxide to silicon dioxide being in the range from

K ₂ O · n SiO ₂ 1 n <1.2 <4

is set.

In the particularly preferred embodiment of the present Invention is a corresponding potassium silicate suspension set.

To further increase chemical resistance and Mechanical strength can be made up of component b) Isocyanate and alkali silicate, as a further component mixtures of or individual alkyl siliconates, especially methyl siliconate and / or organic carboxylic acid esters can be added. The like components are inventively in an amount of 1 % By weight to 10% by weight, based on component b) (e.g. 2% of alkali silicate) used (saponification reaction). The saponification reaction that occurs contributes to increasing the matrix tightness at.

The alkyl siliconates that are used according to the invention can by the general formula

(C _n H _{2 n +1} ) _m SiH _{4- m} · K ₂ O

featured, where
n for an integer ranging from 1 to 4 and
m stands for 1, 2 or 3.

The organic carboxylic acid esters of the present invention correspond to the general formula

(C _x H _{2 x +1} ) COO (C _y H _{2 y +1} )

in which
x and y each independently represent an integer in the range from 1 to 7, preferably 1 to 3. Ethyl acetate is particularly preferred.

The decisive factor in the sense of the present invention is the rapid Absorption of the alkali in the reaction of the isocyanate Metal silicate water of reaction created by the hydrau Chemical binder of the second component.

If the reactivity of the isocyanate is too low none will suffice for the setting speed of the cement appropriate characteristics achieved. Also when choosing the hydrau The chemical binder component must be based on the fact that the open time required for the application is sufficient is appropriate and on the other hand a maximum of durability and technological conformity of the binders and / or Ready mortar with which the substrate is reached.

In a further preferred embodiment, the Binder and / or ready-mixed mortar according to the invention itself known additives for controlling the processing time, the Viscosity and processability in an amount of 0.1 to 2 wt .-%, based on the cement weight in the Component a), for example adipic acid, citric acid, Sulfonates, succinic acid, aluminates or melamines.

Accordingly, in the present invention, this is preferably Ratio of component a) to b) in the range of 1: 1  Parts by weight up to 20: 1 parts by weight, preferably in Range from 5: 3 parts by weight to 10: 1 parts by weight adjust.

In a particularly preferred embodiment of the present Invention is the ratio of components a) and b) such set that the released in the chemical reaction Water from the reaction of isocyanate and alkali metal silicate / Acid ester through the hydraulic binder of the components b) chemically and physically during the setting process is bound.

The binders obtained by means of the present invention and / or ready-mixed mortar can according to a further embodiment form of the present invention for the manufacture of clothing and refurbishment of cementitious and others, with Hydraulic binders manufactured components to increase acid and alkali resistance are used. Soon In time the temperature resistance is up to approx. 1300 ° C raised.

Examples Preliminary note

The substances of component b) were each shortly before Mixing with component a) and with one Bar stirrer mixed thoroughly. The powder component a) was manufactured as a dry mortar mixture. The designated Percentages are percentages by weight. After that the Component b) placed in a laboratory mixer, the dry mortar mixture added in small portions and carefully mixed with a mixing time of 120 seconds.  

The resulting fresh mortar was molded in accordance with DIN 1164 of 4 × 4 × 16 cm and after hiring at a Temperature of 20 ° C and 65% relative humidity stored. The weight and volume determinations were made after the 14-day drying phase and the values fixed ten.

After this 14-day storage, the prisms, which as Reference should serve when placed in a water bath at 30 ° C a degree of immersion of 45%. The remaining prisms were in stored in an acid bath with a 45% immersion degree from an 8% mixture of hydrochloric acid and sulfuric acid duration. Here, too, the temperature became constant at 30 ° C held, in addition, the acid liquid was over a Magnetic stirrer kept in motion. On the 44th day, a Part of the reference prism taken, the deviation in weight and volume determined as a percentage, as well as the bending tension and pressure strength measured.

At the same time, some of the prisms were removed from the acid bath and the volume and weight changes as before determined, and measured the bending and compressive strengths. The remaining prisms of the water bath were in the water bath leave, wash the remaining prisms from the acid bath and in a lye bath consisting of a 12% sodium hydroxide solution solution relocated. The exercise pool also had one here Temperature of 30 ° C, the degree of immersion of the prisms was 45%.

The determined values, such as changes in weight and volume, the compressive and bending tensile strengths are as follows Recorded table.

The high pH values up to 13 delay the gel formation reaction, so that the hardening between K ₂ O · n SiO ₂ / isocyanate and optionally ester can be adjusted to that of the cement between 1 h and 12 h (Vicat DIN 1164).

example 1

Component a):
15% HS cement
25% alumina cement
60% basalt surcharge, grain size 0.3-1.4 mm

Component b):
50% potassium water glass with 35 ° B´
50% MDI (methylene diphenyl diisocyanate)

Ratio component a: b = 5: 3 parts by weight

Example 2

Component a):
15% HS cement
25% alumina cement
60% basalt surcharge, grain size 0.3-1.4 mm

Component b):
50% sodium water glass with 35 ° B´
50% MDI

Ratio component a: b = 5: 3 parts by weight

Example 3

Component a):
15% HS cement
25% alumina cement
60% basalt surcharge, grain size 0.3-1.4 mm

Component b):
50% potassium water glass with 35 ° B´
45% MDI
5% methyl silicone 35% in methanol

Ratio component a: b = 7: 1 parts by weight  

Example 4

Component a):
40% HS cement
60% basalt surcharge, grain size 0.3-1.4 mm

Component b):
60% potassium water glass with 42 ° B´
40% MDI

Ratio component a: b = 3: 1 parts by weight

Example 5

Component a):
40% HS cement
60% quartz, grain size 0.3-1.4 mm

Component b):
60% potassium water glass with 42 ° B´
40% MDI

Ratio component a: b = 3: 1 parts by weight

Example 6

Component a):
40% HS cement
60% lime split aggregate, grain size, sighted, with 5% free lime content, grain size 0.3-1.4 mm

Component b):
60% potassium water glass with 42 ° B´
40% MDI

Ratio component a: b = 3: 1 parts by weight  

Example 7

Component a):
40% Portland cement
60% basalt surcharge, grain size 0.3-1.4 mm

Component b):
60% potassium water glass with 42 ° B´
40% MDI

Ratio component a: b = 3: 1 parts by weight

Example 8

Component a):
40% blast furnace cement
60% basalt surcharge, grain size 0.3-1.4 mm

Component b):
60% potassium water glass with 42 ° B´
40% MDI

Ratio component a: b = 3: 1 parts by weight

Example 9

Component a):
30% Portland cement with C₂S <62%
70% quartz, grain size 0.3-1.4 mm

Component b):
3.2% ethyl acetate
20.0% MDI
3.2% silica ester
73.6% potassium water glass with 35 ° B´

Ratio component a: b = 7: 1 parts by weight  

Example 10

Component a):
30% Portland cement with C₂S <62%
70% quartz, grain size 0.3-1.4 mm

Component b):
62% sodium water glass with 45 ° B´
4% silicic acid ester [(C₂H₅O) ₂ _n + Si _n O _{m -1} with m ≈ 4.5]
4% ethyl acetate
30% tetramethylene diisocyanate

Ratio component a: b = 9: 1 parts by weight

Example 11

Component a):
30% HS cement
70% quartz, grain size 0.3-1.4 mm

Component b):
62% potassium water glass with 45 ° B´
4% silica ester as above
4% ethyl acetate
30% tetramethylene diisocyanate

Ratio component a: b = 9: 1 parts by weight

Example 12

Component a):
25% HS cement
75% quartz, grain size 0.3-1.4 mm

Component b):
60% potassium water glass with 35 ° B´
6% silica ester as above
34% MDI

Ratio component a: b = 10: 1 parts by weight

From the values listed in the table it can be seen that with most mixtures very good resistances are achieved, namely with elongation values between 8 × 10 ^-6 and 16 × 10 ^-6 , depending on the mixing ratio of component a and the mixing ratio from a: b.

table

Claims (14)

1. Acid-resistant and alkali-resistant binders and / or ready-mixed mortar

• a) a hydraulic binder with usual hard impacts of 30 to 70 wt .-%, based on the hy metallic binder,
  marked by
• b) a mixture of aliphatic and / or aromatic diisocyanates and / or polyisocyanates and aqueous alkali metal silicate suspension in a ratio of 10 to 65% by weight of the isocyanate component to 35 to 10% by weight of the SiO ₂ content of the alkali metal silicate suspension.

2. Binder according to claim 1, characterized in that the ratio of isocyanate and aqueous alkali metal silicate suspension in the ratio of 15 to 60 wt .-% of the isocyanate component to 28 to 14 wt .-% of the SiO ₂ content of the alkali metal suspension is set . 3. binder and / or ready-mixed mortar according to claim 1 or 2, characterized by the use of Portland cement, high kiln cement, Eisenportland cement, road cement, sulfadurz cement, Alumina melt cement, pozzolana and / or mixtures thereof as hydraulic binder. 4. binder and / or ready-mixed mortar according to claims 1 to 3, characterized by the use of basalt, quartz, granite, Corundum, lime chippings or their mixtures as hard aggregates. 5. binder and / or ready-mixed mortar according to claims 1 to 4, characterized by the use of isocyanates selects from tolylene di-cyanate, 1,4-phenylene di-isocyanate,  1,3-phenylene diisocyanate, 4,4'-dibenzyl diisocyanate, dialkyldi phenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate and 1,5-naphthylene diisocyanate, as aromatic Diisocyanates and isophorone diisocyanate, 4,4'-methylenebis (cyclo hexyl isocyanate), tetramethylene-1,4-diisocyanate, hexamethylene 1.6-diisocyanate and cyclohexane-1.4-diisocyanate originate as aliphatic diisocyanates. 6. binder and / or ready-mixed mortar according to claim 5, marked is characterized by the use of methylene diphenyl diisocyanate as polyisocyanate. 7. binder and / or ready-mixed mortar according to claims 1 to 6, characterized in that an aqueous alkali metal silic cat suspension with a concentration between 20 ° B´ and 45 ° B´, containing 5 to 60 wt .-% alkali metal silicate is used. 8. binder and / or ready-mixed mortar according to claim 7, characterized characterized in that as alkali metal silicate suspension potassium silicate is used. 9. binder and / or ready-mixed mortar according to claims 1 to 8, characterized by further additions to component b), selected from alkyl siliconates of the general formula (C _n H _{2 n +1} ) _m SiH _{4- m} · K ₂ owole
n for an integer ranging from 1 to 4 and
m represents 1, 2 or 3, and / or organic carboxylic acid esters of the general formula (C _x H _{2 x +1} ) COO (C _y H _{2 y +1} ), where
x and y each independently represent an integer in the range from 1 to 7, in an amount of 1 to 10% by weight, based on component b). 10. binder and / or ready-mixed mortar according to claims 1 to 9, characterized in that known additives, out selects from adipic acid, citric acid, sulfonates, amber acid, aluminates or melamines to control the processing processing time, the viscosity and processability of the Mixture in an amount of 0.1 to 2 wt .-%, based on the Cement weight in component a) are included. 11. Binder and / or ready-mixed mortar according to claims 1 to 10, characterized in that the ratio of the components a): b) between 1: 1 parts by weight and 20: 1 parts by weight is set. 12. binder and / or ready-mixed mortar according to claim 10, characterized in that the ratio of components a): b) between 5: 3 parts by weight and 10: 1 parts by weight is set. 13. Process for the production of binders and / or Ready mortar according to one of claims 1 to 11, wherein the Ratio of component a): b) is set such that  that released in the chemical reaction of component b) Water completely from the hydraulic binder of the component a) is chemically and physically bound. 14. Use of the binders and / or ready-mixed mortar according to Claims 1 to 12 for the production of components with special high chemical and physical load or for the Lining and renovation of cementitious or with hydraulic Binder manufactured components.