EP4255865A1

EP4255865A1 - Composition for watertight coverings

Info

Publication number: EP4255865A1
Application number: EP21816090.1A
Authority: EP
Inventors: Klaus Seip
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2020-12-02
Filing date: 2021-11-30
Publication date: 2023-10-11
Also published as: WO2022117534A1; CN116490479A

Abstract

The present invention relates to compositions for producing watertight coverings comprising A a powdery composition A, where the powdery composition A comprises: a.1 a powdery pozzolanic material comprising a powdery natural pozzolanic material in an amount of at least 30% by weight of the total amount of the pozzolanic material, a.2 powdery non-slaked lime, and a.3 at least one powdery aggregate; and B a liquid composition B comprising an aqueous polymer dispersion made of polymerized ethylenically unsaturated monomers M or a powdery composition B comprising a polymer powder obtained from the aqueous polymer dispersion, where the polymer of the aqueous polymer dispersion has a glass transition temperature Tg of at most +15°C as determined by the differential scanning calorimetry (DSC) method according to ISO 11357-2:2013, and e.g. in the range of -60 to +10°C, in particular in the range of -40 to 5°C, especially in the range of -30 to 0°C. The invention also relates to the use of said compositions for providing watertight coverings. Moreover, the invention relates to a method for providing watertight coverings which comprises mixing the composition A, the polymer of the composition B and water and applying the liquid mixture to a surface where a water-tight covering is required.

Description

Composition for watertight coverings

The present invention relates to compositions for producing watertight coverings comprising a powdery composition A which comprises in turn a powdery pozzolanic material, powdery non-slaked lime and at least one powdery aggregate; and a liquid or powdery composition B which comprises in turn a polymer made of polymerized ethylenically unsaturated monomers M and with a glass transition temperature of at most +15°C either in form of an aqueous polymer dispersion or of a polymer powder obtained from the aqueous polymer dispersion.

TECHNICAL BACKGROUND

In construction, watertight coverings as used for example in water drains, such as sewage or rainwater drains and lines, or as water barrier under tiles in wet rooms (e.g. bathrooms), swimming pools or water tanks are typically based on a cement - organic polymer system. Due to the content of cement binders and optinally mineral aggregates, they are also termed mineral coverings.

Mineral watertight coverings based on cement-polymer systems are, however, not entirely satisfying as regards their resistance against acidic and corrosive substances, and their flexibility or elasticity, which becomes manifest in a dissatisfying crack bridging ability, especially at low temperatures, probably due to the quick setting of typical cement-based binding systems. Good crack bridging properties are not only important for the resistance of watertight coverings against mechanical or temperature stress, but also for the suitability of such systems as mending materials, for example for water-bearing construction, such as rain drains or sewage pipes. Moreover, these cement based systems become brittle over time because the cement contained in them is only partially converted and therefore post-reacts.

Moreover, there is an urgent need to reduce the production and consumption of cement. The currently prevalent cement type, hydraulic cement, is obtained by sintering limestone and aluminosilicate materials such as clay at ca. 1450°C. During sintering, limestone (CaCOs) is calcinated to lime (CaO), setting free CO2. Given the high energy consumption yet for providing the required temperature (generally by burning fossil fuel), the CO2 formation both inherently from the calcination process and from energy production, and of course the sheer amount used worldwide in construction, cement production has become a massive source of the world's CO2 emissions. It is therefore desirable to replace cement at least partially by a material with a smaller carbon footprint. DE 202010 020 080 U1 relates to a dry binder mixture, containing at least one lime carrier, in particular calcium oxide and/or calcium hydroxide, trass and at least one of kaolin and metakaolin. The mixture is in particular cement-free or has only low amounts of cement. It is said to be compatible with old building fabric or natural stone and thus useful in building renovation or restoration as well as in monument preservation and in landscaping and horticulture. The binder is said to have excellent mechanical properties, in particular compressive strength, and not to have the brittleness customary for cement-based binder systems, thus forming less cracks. This system is however not entirely satisfying in applications needing a crack bridging ability at low temperatures. Moreover, this system requires long hardening time.

SUMMARY OF THE INVENTION

It is the object of the present invention to provide compositions for watertight applications, in particular for watertight coverings, which, after setting, are watertight, resistent against acidic and alkaline substances and also against other corrosive substances, in patricular chlorine-containing substances, which have a high elasticity or flexibility, becoming manifest for example in a good crack bridging ability, especially at low temperatures, and has a high bond strength. Setting times should also be satisfactory and the composition should not tend to become brittle over time. Moreover, its production shall be less energy-intensive and CO2 release shall be reduced as compared to cement binder systems. Further, it shall be combinable with recycled materials, e.g. brick powder or powdered rubber, thus allowing to reduce the amount of mineral aggregates such as sand, the natural reservoirs of which have been running off lately.

The object is achieved by compositions comprising a natural pozzolanic material, nonslaked lime, a powdery aggregate and a polymer based on ethylenically unsaturated monomers with a Tg of at most +15°C.

The invention thus relates to compositions for producing watertight coverings, which comprise

A a powdery composition A, where the powdery composition A comprises: a.1 a powdery pozzolanic material comprising a powdery natural pozzolanic material in an amount of at least 30% by weight, based on the total amount of the pozzolanic material, a.2 powdery non-slaked lime, a.3 at least one powdery aggregate; and optionally one of the components a.4 and a.5 a.4 an organic powdery recycling material; and/or a.5 kaolin; and

B a liquid composition B comprising an aqueous polymer dispersion made of polymerized ethylenically unsaturated monomers M or a powdery composition B comprising a polymer powder obtained from the aqueous polymer dispersion made of the polymerized ethylenically unsaturated monomers M, where the polymer of the aqueous polymer dispersion has a glass transition temperature Tg of at most +15°C, in particular at most +10°C, more particularly at most +5°C especially at most 0°C, as determined by the differential scanning calorimetry (DSC) method according to ISO 11357-2:2013, and e.g. in the range of -60 to +15°C, in particular in the range of -60 to +10°C or -50 to +10°C, more particularly in the range of -40 to +5°C or -30 to +5°C, especially in the range of -30 to 0°C or -25°C to 0°C.

The invention also relates to the use of said composition for providing watertight coverings.

Moreover, the invention relates to a method for providing watertight coverings which comprises mixing the composition A, the polymer of the composition B and water and applying the liquid mixture to a surface where a water-tight covering is required.

DETAILED DESCRIPTION OF THE INVENTION

The composition of the invention is not necessarily a physical mixture of compositions A and B, but can constitute any desired combination of the two sub-compositions A and B or of components thereof in which they are not necessarily formulated together. One example of a composition in which compositions A and B are not present as a physical mixture is a two-component kit comprising a first component which comprises the compositions A and a second component which comprises the compositions B. This composition form is for example expedient when a component of one of the compositions interferes with one or more of the components of the other composition. For instance, if composition B is liquid, the water contained therein may start the reaction of components (a.1 ) and (a.2) of composition A, which is of course to be prevented until the composition is put into application at the desired point of time. Composition A may principally also be formulated as a kit of parts, but is preferably formulated as a physical mixture. Pozzolans are natural or artificial siliceous or siliceous and aluminous rock materials and have been used as construction material since antiquity, e.g. as opus caemen- titium in ancient Rome. They are generally formed of silicium dioxide, clay, limestone, iron oxide and alkaline substances under heat. In themselves, they possess little or no value as binders, but, in finely divided form and in the presence of water, react chemically with calcium hydroxide at ordinary temperature to form a material possessing cementitious properties.

Natural pozzolans are either magmatic rock, like volcanic tuff or volcanic trass, or sedimentary rock containing a substantial amount of soluble silicic acid and partially also aluminium oxide (clay). Other pozzolan sources originate from rock metamorphosis caused by meteor strike, like Bavarian trass, Ries trass or Suevit. Trass can thus be of volcanic origin or originate from meteor impact. Strictly speaking, volcanic trass is poz- zolanic volcanic tuff originating from a volcanic eruption of the Laacher See volcano in the Eifel, Germany and occurring in the Brohl and the Nette valleys. In the present invention, “volcanic trass” relates however to any pozzolanic volcanic tuff, irrespective of its origin.

Artificial pozzolans are for example brick powder or fly ash as obtained, for example, from brown coal- or hard coal-fired power stations, waste slag, such as blast furnace slag and steel furnace slag resulting from the manufacture of iron and steel.

Non-slaked lime, also called burnt lime or quicklime, is calcium oxide (CaO).

In general, the term “powdery” with respect to a powdery material means that the material has a particle size of at most 500 pm, in particular of at most 300 pm, especially of at most 200 pm.

For example, “powdery” pozzolanic material means that the pozzolanic material has a particle size of at most 500 pm, in particular of at most 300 pm, preferably of at most 250 pm or of at most 200 pm and specifically at most 100 pm.

“Powdery” non-slaked lime means that the non-slaked lime has a particle size of at most 500 pm, in particular of at most 300 pm, preferably of at most 250 pm or of at most 200 pm and specifically of at most 100 pm.

The particle size in the powdery polymer composition B is not very critical, but is such that the composition B can be easily dispersed in water. It is often in the range given above for the pozzolanic material and typically has a particle size of at most 300 pm or at most 250 pm or at most 200 pm.

Particle sizes and particle size distributions can be determined using a wide variety of measurement methods known per se to the person skilled in the art, for example via sieve analyses according to DIN 66165-2:2016-08, sedimentation or light scattering, e.g. laser diffraction in accordance with DIN ISO 13321 :2004-10. In the present case, given particle sizes of the components of the powdery composition A are either such as indicated by the commercial producer or as determined using sieve analyses according to DIN 66165-2:2016-08.

The remarks made in the following to suitable and preferred embodiments of the invention, in particular to suitable and preferred features of the components of the composition of the invention and their application apply both on their own as well as in any combination with each other.

According to the invention, the pozzolanic material comprises natural pozzolans (in powdery form, of course). The natural pozzolans preferably constitute at least 40% by weight, more preferably at least 50% by weight of the total amount of the pozzolanic material. In particular, they make up for more than 50% by weight, preferably for at least 55% by weight, and in particular for at least 60% by weight of the total amount of the pozzolanic material.

Among the natural pozzolanic materials, preference is given to trass. More preference is given to volcanic trass.

Trass, in particular volcanic trass, preferably constitutes at least 30% by weight, more preferably at least 40% by weight of the total amount of the pozzolanic material. In particular, it is the main constituent of the pozzolanic material, which means that its amount is higher than any other pozzolanic material in the composition A. More particularly, it constitutes more than 50% by weight, even more particularly at least 55% by weight and very particularly at least 60% by weight of the total amount of the pozzolanic material.

In a particular embodiment, the pozzolanic material additionally comprises artificial pozzolanic material, such as brick powder or fly ash as obtained, for example, from brown coal- or hard coal-fired power stations. The artificial pozzolanic material is preferably brick powder or powdery waste slag. The brick powder, also called brick dust or clay dust, is preferably a recycled material, obtained e.g. from comminuting brick waste, e.g. discarded building bricks and roof tiles. Powdery waste slag is ground waste slag, e.g. ground waste slag, such as ground blast furnace slag and ground steel furnace slag resulting from the manufacture of iron and steel.

The artificial pozzolanic material not only reduces the amount of natural pozzolanes, thus allowing to preserve pristine natural resources, but also contributes to the flexibility and elasticity and thus crack resistance of the set system.

In a preferred embodiment, the pozzolanic material comprises or consists of i. 50 to 90% by weight, based on the total amount of pozzolanic material, of powdery trass, in particular of powdery volcanic trass; and

II. 10 to 50% by weight, based on the total amount of pozzolanic material, of brick powder.

More preferably, the pozzolanic material comprises or consists of i. 55 to 85% by weight, based on the total amount of pozzolanic material, of powdery trass, in particular powdery volcanic trass; and

II. 15 to 45% by weight, based on the total amount of pozzolanic material, of brick powder.

More preferably, the pozzolanic material comprises or consists of i. 60 to 80% by weight, based on the total amount of pozzolanic material, of powdery trass, in particular powdery volcanic trass; and

II. 20 to 40% by weight, based on the total amount of pozzolanic material, of brick powder.

As already explained above, the pozzolanic material has a particle size of at most 500 pm, in particular of at most 300 pm, preferably of at most 250 pm or of at most 200 pm. In case of volcanic trass or tuff, the material has in particular a particle size of at most 250 pm, more particularly of at most 200 pm and specifically at most 100 pm.

Preferably, the pozzolanic material has a Blaine specific surface area of at least 5000 cm²/g, more preferably from 5500 to 8500 cm²/g, in particular from 6500 to 7500 cm²/g.

The amount of the overall pozzolanic material is preferably in the range of 30 to 65% by weight, in particular from 40 to 60% by weight, based on the total weight of the powdery composition A. In a specific embodiment, the composition comprises 25 to 40% by weight, in particular 30 to 40% by weight, based on the total weight of the powdery composition A, of volcanic trass and 10 to 25% by weight, in particular 10 to 20% by weight, based on the total weight of the powdery composition A, of brick powder.

The weight ratio of the pozzolanic material to the non-slaked lime is preferably in the range of 2:1 to 5:1 , in particular in the range of 3:1 to 4.8:1.

As already explained above, the non-slaked lime has a particle size of at most 500 pm, preferably of at most 300 pm in particular of at most 250 pm or of at most 200 pm and specifically at most 100 pm.

The amount of the non-slaked lime (a.2) is preferably in the range of 8 to 35% by weight, more preferably in the range of 8 to 20% by weight, in particular in the range of 8 to 15% by weight, based on the total weight of the powdery composition A.

As was observed by the present inventors, the use of non-slaked lime in the present composition instead of slaked lime, which is customarily used in pozzolanic systems, leads to a distinctly faster setting. Moreover, it allows to reduce the amount of calcium needed for setting.

In construction, “aggregate” is a particulate mineral material, in particular a particulate stone material customarily used as reinforcement material to add strength to the overall composite material. The powdery aggregate (a.3) as used in the present composition may be any of the usual construction aggregates, including mineral aggregates such as rock powder and sand; and recycle aggregates produced from the recycling of concrete, which is itself chiefly manufactured from mineral aggregates. Mineral fillers such as powdery dolomite, granites, gravel, sandstone, limestone, basalt and the like can also be used as aggregates. The present powdery aggregate includes moreover also organic concrete “aggregates”, such as rubber or bitumen. The present powdery aggregate includes also mixtures of two or more of the above-listed aggregates.

The overall amount of the powdery aggregate (a.3) is preferably in the range of 15 to 60% by weight, in particular from 25 to 50% by weight, based on the total weight of the powdery composition A.

Preferably, the powdery aggregate comprises sand.

Preferably, the powdery aggregate comprises preferably at least 70% by weight, more preferably at least 80% by weight, in particular at least 90% by weight and up to 100% by weight, based on the total weight of the powdery aggregate, of sand. Preferably, the sand is a combination of medium sand and fine sand.

Fine sand in terms of the present invention is defined in accordance with DIN 4022:1987 and is sand with an equivalent diameter of 0.063-0.2 mm.

Medium sand in terms of the present invention is defined in accordance with DIN 4022:1987 and is sand with an equivalent diameter of 0.2-0.63 mm.

Medium sand and fine sand are preferably present in a weight ratio of from 2:1 to 1 :5, more preferably from 1 :1 to 1 :3, in particular from 1 :1.5 to 1 :3.

In a preferred embodiment, the composition of the invention, in particular the composition A comprises an organic powdery recycling material, such as powdered rubber. The powdered rubber is a recycle material obtained, for example from comminuting discarded tyres and the like. The powdered rubber not only reduces the amount of natural mineral aggregates, such as sand, thus allowing to preserve their pristine natural resources, but also contributes to the flexibility and elasticity and thus crack resistance of the set system.

The organic powdery recycling material has preferably a particle size of at most 500 pm and typically of at least 50 pm.

The organic powdery recycling material, if contained in composition A, is preferably present in an amount of from 5 to 50% by weight, more preferably from 10 to 40% by weight, in particular 10 to 35% by weight, based on the total weight of the powdery aggregate and organic powdery recycling material. Its amount with respect to the composition A, if present, is typically in the range of 2 to 25% by weight, in particular 5 to 15% by weight, based on the total weight of the powdery composition A.

Apart from components (a.1) to (a.3) and optionally (a.4), the composition A may contain other ingredients. One example for an additional ingredient is kaolin (a.5). As was observed, the presence of kaolin leads to a fibrous structure of the set system which enhances its flexibility and crack stability.

Thus, in a preferred embodiment, the powdery composition A additionally comprises powdery kaolin. Kaolin, also known as China clay, is a hydrated aluminum silicate, which can be approximately described by the simplistic and idealized formula AI2O3 ■ 2SiC>2 ■ 2H2O. It is a natural, fine-grained and well crystallized clay mineral with a layered structure.

Kaolin, if contained in composition A, is preferably present in an amount of from 1 to 10% by weight, more preferably from 1 to 5% by weight, in particular from 2 to 3% by weight, based on the total weight of the powdery composition A.

The kaolin has preferably a particle size of at most 500 pm, more preferably of at most 300 pm, in particular of at most 100 pm.

Composition A may moreover contain other additives (a.6) typical for such formulations, such as rheology modifiers (e.g. thickeners, plasticizers), accelerators or retardants (for the setting process). These are typically contained in an overall amount of at most 5% by weight, preferably at most 2% by weight, based on the total weight of composition A.

In a particular embodiment, composition A comprises:

(a.1 .1 ) 25 to 60% by weight of powdery volcanic trass;

(a.1 .2) 0 to 25% by weight of brick powder;

(a.2) 8 to 15% by weight of powdery non-slaked lime;

(a.3) 15 to 60% by weight of sand;

(a.4) 0 to 25% by weight of powdery rubber; and

(a.5) 0 to 10% by weight of kaolin;

(a.6) 0 to 5% by weight of a further additive; in particular a rheology modifier, especially a thickener; where the above percentages add to 100% by weight.

In a further particular embodiment, composition A comprises:

(a.1 .1 ) 25 to 40% by weight of powdery volcanic trass;

(a.1 .2) 10 to 25% by weight of brick powder;

(a.2) 8 to 15% by weight of powdery non-slaked lime;

(a.3) 25 to 50% by weight of sand;

(a.4) 0 to 25% by weight of powdery rubber; and

(a.5) 0 to 10% by weight of kaolin;

More particularly, composition A comprises: (a.1 .1 ) 25 to 40% by weight of powdery volcanic trass;

(a.1 .2) 10 to 25% by weight of brick powder;

(a.2) 8 to 15% by weight of powdery non-slaked lime;

(a.3) 25 to 35% by weight of sand;

(a.4) 5 to 15% by weight of powdery rubber; and

(a.5) 0 to 10% by weight of kaolin;

(a.6) 0 to 2% by weight of a further additive; in particular a rheology modifier, especially a thickener; where the above percentages add to 100% by weight.

Specifically, composition A comprises:

(a.1 .1 ) 30 to 38% by weight of powdery volcanic trass;

(a.1 .2) 10 to 20% by weight of brick powder;

(a.2) 8 to 13% by weight of powdery non-slaked lime;

(a.3) 25 to 30% by weight of sand;

(a.4) 5 to 15% by weight of powdery rubber; and

(a.5) 1 to 5% by weight of kaolin;

(a.6) 0 to 1 .5% by weight of a further additive; in particular a rheology modifier, especially a thickener; where the above percentages add to 100% by weight.

Very specifically, composition A comprises:

(a.1 .1 ) 30 to 34% by weight of powdery volcanic trass;

(a.1 .2) 14 to 18% by weight of brick powder;

(a.2) 8 to 12% by weight of powdery non-slaked lime;

(a.3) 26 to 30% by weight of sand;

(a.4) 8 to 12% by weight of powdery rubber; and

(a.5) 2 to 3% by weight of kaolin;

(a.6) 0.1 to 1 .5% by weight of a further additive; in particular a rheology modifier, especially a thickener; where the above percentages add to 100% by weight.

The composition B is either liquid or powdery.

In case that composition B is liquid, it comprises an aqueous polymer dispersion made of polymerized ethylenically unsaturated monomers M, where the polymer of the aqueous polymer dispersion has a glass transition temperature Tg of at most +15°C, in particular at most +10°C, more particularly at most +5°C, especially at most 0°C. Here and in the specification the values given for the glass transition temperature Tg refer to values which are determined by the differential scanning calorimetry (DSC) method according to ISO 11357-2:2013, preferably with sample preparation according to ISO 16805:2003. In case that composition B is powdery, it comprises a polymer powder obtained from the above-described aqueous polymer dispersion, where the polymer of the aqueous polymer dispersion has a glass transition temperature Tg of at most +15°C, in particular at most +10°C, more particularly at most +5°C, especially at most 0°C. Generally, the glass transition temperature Tg is at least -60°C, frequently at least -50°C, in particular at least -40°C more particularly at least -30°C and especially at least -25°C.

The following remarks regarding the polymer apply both for the liquid and the powdery form of composition B.

Generally, the Tg of the polymer is in the range of -60 to +15°C. Preferably, the Tg of the polymer is in the range of -50 to +10°C, in particular in the range of -40 to +5°C or - 30 to +5°C, especially in the range of -30 to 0°C or -25 to 0°C.

The polymers of composition B are insoluble in water and are present in the form of disperse polymer particles within the aqueous coating compositions.

The average diameter of the polymers (polymer particles) present in aqueous dispersion form of composition B is generally in the range from 10 to 1000 nm, frequently in the range from 20 to 500 nm, e.g. from 100 to 400 nm. By average particle diameter this specification means the Z average particle diameter as determined by dynamic light scattering (also termed quasielastic light scattering) of an aqueous polymer dispersion diluted with deionized water to 0.001 to 0.5% by weight at 22°C by means of a HPPS from Malvern Instruments, England. What is reported is the cumulant Z average diameter calculated from the measured autocorrelation function (ISO Standard 13321).

The aqueous dispersion of the polymer is generally a polymer obtained by emulsion polymerization of ethylenically unsaturated monomers M, hereinafter also referred to as polymer emulsions. Polymer emulsions are familiar to the skilled person and are prepared, for example, in the form of an aqueous polymer dispersion by means of radically initiated aqueous emulsion polymerization of ethylenically unsaturated monomers M. This technique has been exhaustively described in the art, and is therefore well known to the skilled person [cf., e.g., Encyclopedia of Polymer Science and Engineering, vol. 8, pages 659 to 677, John Wiley & Sons, Inc., 1987; D. C.

Blackley, Emulsion Polymerisation, pages 155 to 465, Applied Science Publishers, Ltd., Essex, 1975; D. C. Blackley, Polymer Latices, 2nd edition, vol. 1 , pages 33 to 415, Chapman & Hall, 1997; H. Warson, The Applications of Synthetic Resin Emulsions, pages 49 to 244, Ernest Benn, Ltd., London, 1972; J. Piirma, Emulsion Polymerisation, pages 1 to 287, Academic Press, 1982; F. Holscher, Dispersionen synthetischer Hochpolymerer, pages 1 to 160, Springer-Verlag, Berlin, 1969, and patent specification DE-A 40 03422], The radically initiated aqueous emulsion polymerization is normally accomplished by dispersing the ethylenically unsaturated monomers in aqueous medium, generally with accompanying use of dispersing assistants, such as emulsifiers and/or protective colloids, and polymerizing them by means of at least one water- soluble radical polymerization initiator. In the aqueous polymer dispersions obtained, the residual amounts of unreacted ethylenically unsaturated monomers are frequently lowered by chemical and/or physical techniques that are likewise known to the skilled person [see, for example, EP-A 771328, DE-A 19624299, DE-A 19621027,

DE-A 19741184, DE-A 19741187, DE-A 19805122, DE-A 19828183, DE-A 19839199, DE-A 19840586, and 19847115]; the polymer solids content is adjusted to a desired level by dilution or concentration; or the aqueous polymer dispersion is admixed with further customary adjuvants, such as bactericidal, foam-modifying or viscositymodifying additives, for example.

As well as these so-called primary aqueous polymer dispersions, the skilled person also knows of what are called secondary aqueous polymer dispersions. These are understood to be aqueous polymer dispersions in whose preparation the polymer is generated outside of the aqueous dispersing medium, as for example in solution in a suitable nonaqueous solvent. This solution is subsequently transferred into the aqueous dispersing medium, and the solvent is separated off with dispersing, generally by distillation.

Preferably, the aqueous polymer dispersion is a primary aqueous polymer dispersion, in particular an aqueous polymer dispersion, which is obtained by aqueous emulsion polymerization of ethylenically unsaturated monomers M.

Preferably, the polymer is a copolymer of ethylenically unsaturated monomers M. The term copolymer as used herein refers to polymers which are made of two or more, e.g. 2, 3, 4, 5 or 6 or more different ethylenically unsaturated monomers M. Preferably the copolymer comprises both ethylenically unsaturated comonomers with a rather low and with a higher solubility in water, where the comonomers of rather low solubility preferably constitute the major part of the polymer. Ethylenically unsaturated monomers of low water-solubility are those having a solubility in water of not more than 50 g/l at 20°C and 1 bar. These monomers are hereinafter referred to as monomers M1. Monomers of higher water-solubility are those having a solubility in water of at least 60 g/l at 20°C and 1 bar. These monomers are hereinafter referred to as monomers M2.

Preferably, the polymer of the aqueous polymer dispersion is composed of i) 80 to 99.9 pphm, more particularly 85 to 99.5 pphm, of at least one monoethylenically monomer M.1 having a water-solubility of not more than 50 g/l at 20°C and 1 bar; ii) 0.1 to 20 pphm, more particularly 0.5 to 15 pphm, of at least one monoethylenically monomer M.2 having a water-solubility of at least 60 g/l at 20°C and 1 bar.

The term “pphm” means part per hundred parts of monomers and is an abbreviation of the term “% by weight, based on the total amount of monomers”.

Examples for monomers M.1 are: esters of acrylic and/or methacrylic acid with alkanols having 1 to 20 C atoms, such as methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, 2-butyl acrylate, tert-butyl acrylate, n-pentyl acrylate, isopentyl acrylate, n-hexyl acrylate, n-heptyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, 2-propylpentyl acrylate, n-decyl acrylate, 2-propylheptyl acrylate, Cw isoamyl guerbet acrylate, 1 -propylheptyl acrylate, lauryl acrylate and stearyl acrylate. Examples of C1-C20 alkyl esters of methacrylic acid include, but are not limited to methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, 2-butyl methacrylate, tert-butyl methacrylate, n-pentyl methacrylate, isopentyl methacrylate, n-hexyl methacrylate, n-heptyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, 2-propylpentyl methacrylate, n-decyl methacrylate, 2-propylheptyl methacrylate, Cw isoamyl guerbet methacrylate, 1 -propylheptyl methacrylate, lauryl methacrylate and stearyl methacrylate; esters of acrylic and/or methacrylic acid with cycloalkanols having 3 to 10 C atoms, in particular 5 to 10 C atoms, such as cyclopropylacrylate, cyclopentyl acrylate, cyclohexyl acrylate, 4-methylcyclohexyl acrylate, 4-tert-butylcyclohexyl acrylate, cyclopentyl methacrylate, cyclohexyl methacrylate, 4-methylcyclohexyl methacrylate and 4-tert-butylcyclohexyl methacrylate; vinylaromatic hydrocarbons such as styrene, 2-methylstyrene, 4-methylstyrene, 2-n-butylstyrene, 4-n-butylstyrene or 4-n-decylstyrene; conjugated alkadienes, such as butadiene or isoprene; olefins and haloolefins such as ethylene, propene, vinyl chloride, and vinylidene chloride; vinyl esters and allyl esters of saturated C1-C12 alkanoic acids such as vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl hexanoate, vinyl octanoate, vinyl laurate, vinyl stearate, vinyl esters of Versatic acid, allyl formate, allyl acetate, allyl propionate, allyl butyrate or allyl laurate.

Preferred monomers M1 are esters of acrylic with alkanols having 1 to 10 C atoms esters of methacrylic acid with alkanols having 1 to 10 C atoms, vinylaromatic hydrocarbon compounds, specifically styrene, conjugated alkadienes, specifically butadiene, vinyl esters of saturated Ci-Cs alkanoic acids, specifically vinylacetate, and olefins, specifically ethylene and combinations thereof.

Examples for monomers M.2 are monoethylenically unsaturated acidic monomers M2. a such as monoethylenically unsaturated monocarboxylic acids having 3 to 8 C atoms such as acrylic acid, methacrylic acid or itaconic acid; ethylenically unsaturated sulfonic acids and their salts such as vinylsulfonic acid, allylsulfonic acid, sulfoethyl acrylate, sulfoethyl methacrylate, sulfopropyl acrylate, sulfopropyl methacrylate, 2-hydroxy-3-acryloyloxypropylsulfonic acid, 2-hydroxy- 3-methacryloyloxypropylsulfonic acid, styrenesulfonic acids, and 2-acrylamido-2- methylpropanesulfonic acid, especially their salts, more particularly their sodium salts; and monoethylenically unsaturated neutral monomers M2.b, such as primary amides of monoethylenically unsaturated monocarboxylic acids having 3 to 8 C atoms such as acrylamide and methacrylamide; monoethylenically unsaturated monomers which carry urea groups or keto groups, such as 2-(2-oxoimidazolidin-1-yl)ethyl (meth)acrylate,

2-ureido(meth)acrylate, N-[2-(2-oxo-oxazolidin-3-yl)ethyl] methacrylate, acetoacetoxyethyl acrylate, acetoacetoxypropyl methacrylate, acetoacetoxybutyl methacrylate, 2-(acetoacetoxy)ethyl methacrylate, diacetoneacrylamide (DAAM) and diacetonemethacrylamide; esters of acrylic and/or methacrylic acid with alkandiols having 2 to 4 C atoms, such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxyethyl ethacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate,

3-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, 3-hydroxybutyl acrylate, 3-hydroxybutyl methacrylate, 4-hydroxybutyl acrylate or 4-hydroxybutyl methacrylate; Preferably, the polymer of the polymer dispersion contains not more than 2 pphm of monoethylenically unsaturated monomers having an acid group. In particular, the polymer of the polymer dispersion contains at most 0.5 pphm of monomers having a carboxylic acid group, such as acrylic acid, methacrylic acid or itaconic acid. More preferably, the polymer does not contain any monomers having a carboxylic acid group. Preferably, the polymer contains at most 1 pphm of monomers having a sulfonic acid group. Preferably, the monomers M2 comprise at least 80% by weight, based on the total weight of the monomers M2 of neutral monomers M2.

In addition ot the aformementioned monoethylenically unsaturated monomers monomers M 1 and M2, the monomers M may comprise a small amount of ethylenically unsaturated monomers M3, which bear at least 2, e.g. 2 to 6 non-conjugated ethylenically unsaturated double bonds. These monomers will result in a crosslinking of the polymer chain during polymerization and thus are referred to as crosslinking monomers M3. Exemplary crosslinking monomers include divinylbenzene, diesters or triesters of dihydric and trihydric alcohols with monoethylenically unsaturated C3-C6 monocarboxylic acids, e.g., di(meth)acrylates, tri(meth)acrylates), and tetra(meth)acrylates, e.g. alkylene glycol diacrylates and dimethacrylates, such as ethylene glycol diacrylate, 1 ,3-butylene glycol diacrylate, 1 ,4-butylene glycol diacrylate and propylene glycol diacrylate, trimethylolpropan triacrylate and trimethacrylate, pentaerythrit triacrylate and pentaerythrit tetraacrylate, but also vinyl and allyl esters of ethylenically unsaturated acids such as vinyl methacrylate, vinyl acrylate, allyl methacrylate, allyl acrylate, and divinyl and diallyl esters of dicarboxyilic acids, such as diallyl maleate and diallyl fumarate and also methylenebisacrylamide. The amount of said monomers M3 will usually not exceed 2 pphm and is in particular below 1 pphm.

In addition to the aforementioned monoethylenically unsaturated monomers monomers M1 and M2, the monomers M may comprise a small amount of ethylenically unsaturated monomers M4, which have one unsaturated double bond and a further reactive group susceptible to a post-crosslinking reaction, including monoethylenically unsaturated monomers containing a keto group, e.g., aceto- acetoxyethyl(meth)acrylate or diacetonacrylamide; monoethylenically unsaturated monomers, which bear a dialkoxyalkylsilane group or a trialkoxysilane group (silane monomers), e.g. vinyl triethoxysilane, 3-methacryloxypropyl trimethoxysilane and 3-mercaptopropyl trimethoxy silane, monoethylenically unsaturated monomers, which bear an epoxy group, such as monoeglycidyl allyl ether, glycidyl acrylate, glycidyl methacrylate, 2-glycidyloxyethyl acrylate, 2-glycidyloxyethyl methacrylate, 3-glycidyloxypropyl acrylate, 3-glycidyloxypropyl methacrylate, 4-glycidyloxybutyl acrylate 4-glycidyloxybutyl methacrylate, 3,4-epoxybutyl acrylate, 3,4-epoxybutyl methacrylate, 4,5-epoxypent-2-yl acrylate or 4,5-epoxypent-2-yl methacrylate with preference given to epoxy functionalized (meth)acrylate monomers; N-alkylolamides of a,p-monoethylenically unsaturated carboxylic acids having 3 to 10 carbon atoms and esters thereof with alcohols having 1 to 4 carbon atoms, e.g. N-methylolacrylamide and N-methylolmethacrylamide.

More preferably, the polymer is a copolymer of at least one monovinylaromatic monomer M1 a and at least one further monomer M1 b selected from conjugated aliphatic dienes, Ci-Cw-a Iky I esters of acrylic acid, Ci-Cw-alkylesters of methacrylic acid, C5-C10- cycloalkylesters of acrylic acid and Cs-Cw-cycloalkylesters of methacrylic acid and mixtures thereof, optionally one or more further comonomers M2 and optionally one or more further comonomers M3 and/or M4.

The monovinylaromatic monomer M1 a is preferably styrene.

Monomer M1 b is preferably selected from conjugated aliphatic dienes, especially butadine, Ci-Cw-a Iky I esters of acrylic acid, hereinafter referred to as C1-C10- a Iky I acylates, and Ci-Cw-alkylesters of methacrylic acid, hereinafter referred to as Ci-Cio-alkylmethacylates. In particular, M1 b is selected from butadiene, C1-C10- alkylacrylates Ci-C4-alkyl methacylates. Examples of Ci-Cw-a Iky I acrylates are methyl acrylate, ethyl acrylate, n-butyl acrylate, tert-butylacrylate, n-hexyl acrylate, octyl acrylate, 2-ethylhexyl acrylate and 2-propylheptyl acrylate. Among these, preference is given to n-butyl acrylate and 2-ethylhexyl acrylate. Examples of C1-C4- a Iky I meth acrylates are methylmethacrylate, ethyl meth aery I ate and n-butylmethacrylate.

Herein, aqueous polymer dispersions, wherein the monomer M1a is styrene and the further monomers M1 b is selected from alkylesters, in particular Ci-Cw-a Iky I esters of acrylic acid and/or methacrylic acid and cycloalkylesters, in particular Cs-Cw-cycloal- kylesters of acrylic acid and/or methacrylic acid and mixtures thereof are termed aqueous polymer dispersions of styrene-acrylate copolymers. The styrene acrylate copolymers in these dispersions may contain one or more polymerized monomers M2, M3 and/or M4.

Herein, aqueous polymer dispersions, wherein the monomer M1 a is styrene and the further monomer M1 b comprises butadiene or is butadiene are termed aqueous polymer dispersions of styrene-butadiene copolymers. The styrene butadiene copolymers in these dispersions may contain one or more polymerized monomers M2, M3 and/or M4. Also suitable are aqueous polymer dispersions wherein the monomers M1 comprise vinylacetate, in particular a combination of vinylacetate and at least one C2-C6-monoole- fine, such as ethylene, or a combination of vinylacetate, at least one C2-C6-monoole- fine, such as ethylene, and a further monomer M 1 b as defined above, which is preferably selected from vinylesters of C2-C12 alkanoic acids, in particular vinylesters of branched C4-C12 alkanoic acids, e. g. Koch acids, such as pivalic acid or Verstatic® acids, such as VeoVa 9 vinyl ester, VeoVa 10 vinyl ester and VeoVa EH vinyl ester of Hexion, C2-Cw-a Iky I esters of acrylic acid, Ci-Cw-a Iky I esters of methacrylic acid, C5-C10- cycloalkylesters of acrylic acid and Cs-Cw-cycloalkylesters of methacrylic acid and mixtures thereof. Hereinafter polymer dispersions, wherein the monomers M1 comprise combination of vinylacetate, ethylene, and optionally a further monomer M1 b as defined above, are also termed aqueous polymer dispersions of ethylene-vinylacetate copolymers

Also suitable are aqueous polymer dispersions, which are similar to the styrene acrylate polymer dispersions, where at least a portion of the styrene is replaced by acrylonitrile. In these polymer dispersions the monomers M comprise acrylonitrile and optionally styrene as monomers M1a”, and at least one further monomer M1 b”, which is selected from the group of Ci-Cw-a Iky I esters of acrylic acid, Ci-Cw-alkylesters of methacrylic acid, Cs-Cw-cycloalkylesters of acrylic acid and Cs-Cw-cycloalkylesters of methacrylic acid and mixtures thereof, optionally one or more further comonomers M2 and optionally one or more further comonomers M3 and/or M4. These aqueous polymer dispersions are herein termed aqueous polymer dispersions of acrylonitrile-acrylate copolymers.

Also suitable are aqueous all acrylic-polymer dispersions. In these polymer dispersions the monomers M comprise at least one Ci-C4-alkylesters as a monomer M1 a’, in particular methyl methacrylate, and at least one further monomer M1 b’, which is selected from the group of Ci-Cw-a Iky I esters of acrylic acid, Cs-Cw-a Iky I esters of methacrylic acid, Cs-Cw-cycloalkylesters of acrylic acid and Cs-Cw-cycloalkylesters of methacrylic acid and mixtures thereof, optionally one or more further comonomers M2 and optionally one or more further comonomers M3 and/or M4.

Even more preferably, the aqueous polymer dispersion is selected from aqueous polymer dispersions of copolymers of a

- vinylaromatic compound M 1 a, in particular styrene and at least one further monomer M1 b selected from conjugated aliphatic dienes, alkylesters, in particular Ci-Cw-a Iky I esters of acrylic acid, alkylesters, in particular Ci-Cw-a Iky I esters of methacrylic acid, cycloalkyl esters, in particular Cs-Cw-cycloalkylesters of acrylic acid and cycloalkylesters, in particular Cs-Cw-cycloalkylesters of methacrylic acid and mixtures thereof, e.g. styrene-butadiene copolymers or styreneacrylate copolymers; and aqueous polymer dispersions of vinylesters and a-olefins, such as ethylene, e.g. aqueous polymer dispersions ethylene-vinylacetate copolymers.

In particular, the aqueous polymer dispersion is selected from aqueous polymer dispersions of styrene-acrylate copolymers, aqueous polymer dispersion of styrene-butadiene copolymers, aqueous polymer dispersions of all-acrylic copolymers, aqueous polymer dispersions of acrylonitrile-acrylate copolymers and aqueous polymer dispersion of ethylene-vinylacetate copolymers with particular preference given to aqueous polymer dispersions of styrene-acrylate copolymers and aqueous polymer dispersion of styrene-butadiene copolymers.

In a more preferred embodiment, the monomers M which form the polymer of the aqueous polymer dispersion comprise: i. 80 to 99.9% by weight, in particular 85 to 99.5% by weight, based on the total amount of monomers M, of at least one monomer M1 , which is selected from a combination of at least one monovinylaromatic monomer M1a and at least one further monomer M1 b selected from conjugated aliphatic dienes, alkylesters, in particular Ci-Cw-a Iky I esters of acrylic acid and/or methacrylic acid and cycloalkylesters, in particular Cs-Cw-cycloalkylesters of acrylic acid and/or methacrylic acid and mixtures thereof,

II. 0.1 to 15% by weight, in particular 0.5% to 10% by weight, based on the total amount of monomers M, of at least one monomer M2 selected from neutral monomers having a solubility in water of at least 60 g/L at 20°C, and ill. optionally 0 to 5% by weight, e.g. 0.1 to 5% by weight, based on the total amount of monomers M, of one or more monomers M4.

Monomer M2 is preferably selected from primary amides of monoethylenically unsaturated monocarboxylic acids having 3 to 8 C atoms, such as acrylamide and methacrylamide, and esters of acrylic and/or methacrylic acid with alkandiols having 2 to 4 C atoms, such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate,

2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl acrylate,

3-hydroxypropyl methacrylate, 3-hydroxybutyl acrylate, 3-hydroxybutyl methacrylate,

4-hydroxybutyl acrylate or 4-hydroxybutyl methacrylate. More preferably, M2 is selected from acrylamide, methacrylamide and esters of methacrylic acid with alkandiols having 2 to 4 C atoms, such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl methacrylate, 3-hydroxybutyl methacrylate or 4-hydroxybutyl methacrylate. Specifically, M2 is selected from the group consisting of acrylamide, methacrylamide, 2-hydroxyethyl acrylate and

2-hydroxyethyl methacrylate.

The monomers M4 which effect self-crosslinking of the polymer are preferably monomers having at least one ethylenically unsaturated double bond and an epoxy group, such as a glycidyl group, e.g. glycidyl allyl ether, glycidyl acrylate, glycidyl methacrylate, 2-glycidyloxyethyl acrylate, 2-glycidyloxyethyl methacrylate,

3-glycidyloxypropyl acrylate, 3-glycidyloxypropyl methacrylate, 4-glycidyloxybutyl acrylate 4-glycidyloxybutyl methacrylate, 3,4-epoxybutyl acrylate, 3,4-epoxybutyl methacrylate, 4,5-epoxypent-2-yl acrylate or 4,5-epoxypent-2-yl methacrylate. Specifically, 2-glycidyloxyethyl acrylate is used.

In particular, the monomers M which form the polymer of the aqueous polymer dispersion comprise: iv. 80 to 99.9% by weight, in particular 85% to 99.5% by weight, based on the total amount of monomers M, of at least one monomer M1 , which is selected from a combination of styrene and at least one further monomer M1 b selected from butadiene and alkylesters, in particular Ci-Cw-a Iky I esters of acrylic acid, v. 0.1 to 15% by weight, in particular 0.5% to 10% by weight, based on the total amount of monomers M, of at least one monomer M2 selected from acrylamide, methacrylamide and esters of methacrylic acid with alkandiols having 2 to 4 C atoms, and vi. optionally 0 to 5% by weight, based on the total amount of monomers M, of one or more of the above-listed monomers having an epoxy group.

In an aqueous composision B, the polymer content is preferably from 20 to 70% by weight, more preferably from 30 to 65% by weight and in particular from 40 to 60% by weight, based on the total weight of the aqueous composition B.

The aqueous polymer dispersion, in particular the aqueous polymer dispersions of sty- rene-butadiene copolymers, the aqueous polymer dispersions of styrene-acrylate copolymers, the aqueous polymer dispersions of all-acrylic copolymers, the aqueous polymer dispersions of acrylonitrile-acrylate copolymers and the aqueous polymer dispersions of vinyl acetate homo and copolymers, typically contains at least one surface active compound. The surface active compound serves to stabilize the aqueous dispersion of the polymer by keeping the particles of the polymer dispersed. The surface active compound may be an emulsifier, a protective colloid or a mixture of both of them. The emulsifier and the protective colloid are distinct from each other by their weight-average molar mass M_w. An emulsifier has typically a weight-average molar mass M_w in general below 2000, while the weight-average molar mass M_w of the protective colloid may be up to 50 000, in particular from above 2000 to up to 50000. Typically, the amount of the surface active compound is in the range from 0.1 to 10% by weight, in partiuclar in the range from 0.5 to 5% by weight, based on the total amount of polymer in the aqueous polymer dispersion.

Preferably, the surface active compound comprises one or more emulsifiers. The emulsifier is non-ionic, anionic, or cationic. In case of employing a mixture of emulsifiers, their compatibility has to assured, which can be evaluated in case of doubt by preliminary tests. Typically, an anionic emulsifier is compatible with another anionic emulsifier or a non-ionic emulsifier. Similarly, a cationic emulsifier is typically compatible with another cationic emulsifier or a non-ionic emulsifier. Preferably, the emulsifier is an anionic emulsifier, a combination of two or more anionic emulsifier or a combination of at least one anionic emulsifier and at least one non-ionic emulsifier.

Non-ionic emulsifier are, for example, ethoxylated Cs-Cse fatty alcohols having a degree of ethoxylation of from 3 to 50 (= ethylene oxide units [EO]: 3-50) and ethoxylated mono-, di- and tri-C4-Ci2 alkylphenols having a degree of ethoxylation of from 3 to 50. Examples of customary nonionic emulsifiers are the Emulgin B grades (cetyl/stearyl alcohol ethoxylates, RTM BASF), Dehydrol LS grades (fatty alcohol ethoxylates, EO units: 1-10, RTM BASF), Lutensol A grades (Ci2Ci4-fatty alcohol ethoxylates, EO units: 3-8, RTM BASF), Lutensol AO grades (C13C15-OXO alcohol ethoxylates, EO units: 3-30), Lutensol AT grades (Ci₆Ci8-fatty alcohol ethoxylates, EO units: 11-80), Lutensol ON grades (Cw-oxo alcohol ethoxylates, EO units: 3-11) and Lutensol TO grades (C -oxo alcohol ethoxylates, EO units: 3-20). Here and in the following the phrase “EO units” means the number average of ethylene oxide repeating units in the emulsifier.

Anionic emulsifiers include for example the alkali metal salts of dialkyl esters of sulfosuccinic acid, the alkali metal salts and the ammonium salt of C8-C12 alkyl sulfates, the alkali metal salts and the ammonium salts of C12-C18 alkylsulfonic acids, the alkali metal salts and the ammonium salts of C9-C18 alkylarylsulfonic acid, the alkali metal salts and the ammonium salts of sulfuric acid monoesters of ethoxylated C12-C18 alkanols (EO units: 4-30) or a sulfuric acid monoester of an ethoxylated (C4-C12 alkyl)phe- nol (EO units: 3-50). As further anionic emulsifiers, compounds of the general formula I wherein R^a and R^b are each a H atom or C4-C24-alkyl and are not both H atoms at the same time, and Mi⁺ and M2⁺ can be alkali metal ions and/or ammonium, are also useful. In the general formula I, R^a and R^b are preferably linear or branched alkyl radicals having from 6 to 18 carbon atoms, in particular 6, 12 or 16 carbon atoms, or hydrogen atoms, where R^a and R^b are not both hydrogen atoms at the same time. Mi⁺ and M2⁺ are preferably sodium, potassium or ammonium, with sodium being particularly preferred. A compound of general formula I, in which Mi⁺ and M2⁺ are both sodium, R^a is a branched alkyl radical having 12 carbon atoms and R^b is hydrogen or R^a is particularly advantageous. Use is frequently made of industrial mixtures which have a proportion of from 50 to 90% by weight of the monoalkylated product, for example Dowfax® 2A1 (RTM The Dow Chemical Corp.). The compounds of general formula I are commonly known, e.g. from US-A 4 269 749, and commercially available. Further anionic emulsifiers are fatty alcohol phosphates, alkylphenol phosphates, alkyl polyglycol ether phosphates, alkyl polyalkylene oxide phosphates, and fatty alcohol ether phosphates and the salts thereof, in particular the alkalimetal salts and ammonium salts thereof, with particular preference given to the alkalimetal salts such as sodium salts.

A comprehensive description of suitable emulsifiers may be found in Houben-Weyl, Methoden der organischen Chemie, volume XIV/1 , Makromolekulare Stoffe, Georg- Thieme-Verlag, Stuttgart, 1961 , pages 192 to 208.

Like the aforementioned emulsifiers, suitable protective colloids may be non-ionic, anionic or cationic. Examples of protective colloids are poly(vinyl alcohols), poly(alkylene glycols), poly(acrylic acids) and the alkali metal salt thereof, poly(methacrylic acids) and the alkali metal salt thereof and gelatin derivatives. Anionic protective colloid can also be a copolymer, containing a suitable amount of at least one anionic monomer, such as acrylic acid, methacrylic acid, maleic acid, 2-acrylamido-2-methylpropane sulfonic acid, para-vinylphenyl sulfonic acid or salt forms thereof, preferably alkali metal salts thereof, in polymerized form. Examples of cationic protective colloids are homopolymers and copolymers containing a sufficient amount of cationic monomers, in particular monoethylenically unsaturated monomers having one or more amino groups, which are N-protonated or N-alkylated. Examples include N-protonated and N-alkylated derivatives of homopolymers or copolymers of N -vinylform am ide in their at least partly hydrolyzed form, homopolymers or copolymers of N-vinylacetamide in their at least partly hydrolyzed form, N-protonated and N-alkylated derivatives of homopolymers or copolymers of N-vinylcarbazole, N-protonated and N-alkylated derivatives of homopolymers or copolymers of 1-vinylimidazole, N-protonated and N-alkylated derivatives of homopolymers or copolymers of 2-vinylimidazole, N-protonated and N-alkylated derivatives of homopolymers or copolymers of 2-vinylpyridine, N-protonated and N-alkylated derivatives of homopolymers or copolymers of 4-vinylpyridine, N-protonated and N-al- kylated derivatives of homopolymers or copolymers of amine-group-bearing acrylates, N-protonated and N-alkylated derivatives of homopolymers or copolymers of amine- group-bearing methacrylates, wherein the nitrogen of the amine-group is protonated at a pH below 7 or is permanently positively charged, for example by alkylation. Further comonomers in such cationic protective colloids may be acrylamide, methacrylamide and N-vinyl pyrrolidone.

The protective colloids are distinct from the polymers dispersed in the aqueous polymer dispersion as they are water-soluble or water dispersible. The term “water-soluble or water dispersible” is understood that the corresponding protective colloid can be dissolved or dispersed in deionized water at 20°C and 1013 mbar in an amount of at least 10 g/L polymer such that the resulting aqueous solution has either no measurable particle size or a particle size of at most 20 nm as determined by dynamic light scattering in accordance with DIN 22412:2008.

A comprehensive description of suitable protective colloids may be found in Houben- Weyl, Methoden der organischen Chemie, volume XIV/1 , Makromolekulare Stoffe, Georg-Thieme-Verlag, Stuttgart, 1961 , pages 411 to 420.

The composition of the invention contains the polymer - either in powdery form or in dispersion - in such an amount that the weight ratio of polymer to the powdery composition A is in the range of 1 :10 to 1 :1 and in particular in the range of 1 :5 to 1 :1.

The composition of the invention may moreover contain further auxiliaries, such as

- wetting agents or dispersants,

- thickeners,

- flow control agents, biocides, and defoamers.

If compositions A and B are formulated separately, the auxiliaries are generally incorporated in composition B. Flow control agents may however also be incorporated in composition A. Suitable wetting agents or dispersants are, for example, sodium, potassium or ammonium polyphosphates, alkali metal salts and ammonium salts of acrylic or maleic anhydride polymers, polyphosphonates, such as sodium 1-hydroxyethane-1 ,1- diphosphonate, and also salts of naphthalenesulfonic acids, more particularly their sodium salts. Among the above dispersants, preference is given to polymeric dispersants, such as alkali metal salts and ammonium salts of acrylic or maleic anhydride polymers. Specifically, a metal salt of polyacrylic acid is used.

Preferably, the polymeric dispersant is contained in an amount of from 0.1 to 2% by weight, in particular from 0.1 to 1 % by weight, based on the total weight of the polymer of composition B.

Suitable thickeners are, for example, associative thickeners, such as polyurethane thickeners.

Suitable defoamers are for example silicone antifoams and magnesium stearate. Preferably, the defoamer is contained in an amount of from 0.05 to 2% by weight, in particular from 0.1 to 1 % by weight, based on the total weight of the polymer of composition B.

In case that composition B is liquid, it is expedient to keep compositions A and B physically apart in order to preclude setting of the components of composition A by the presence of water in the composition B. In this case, the composition of the invention is preferably formulated as a two kits of part formulation of the powdery composition A as a first part of the formulation and the liquid composition B as a separately formulated second part of the formulation.

In case that composition B is powdery, it is principally also possible to formulate the composition of the invention as a two kits of part formulation. Preference is however given to formulate the composition of the invention as a physical mixture of the powdery composition A and the powdery composition B.

The composition of the invention in form of a physucal mixture is obtained by intimately mixing the various components in suitable mixing apparatuses.

The present invention relates moreover to the use of the composition of the invention for providing watertight coverings, and to a method for providing watertight coverings which comprises mixing the composition A, the polymer of the composition B and water and applying the flowable mixture to a surface where a water-tight covering is required. In the method of the invention, the amount of water is preferably chosen such that the weight ratio of water to the pozzolanic material is in the range of 1 :1 to 2:1.

The covering resulting after setting of the applied material is watertight and resistant against acidic substances, alkaline substances and chlorine-containing substances, such as various acids of chlorine, e.g. hypochloric acid, as occurring in swimmingpools and other water tanks in which water is treted against fouling. The covering has a high bond strength and has a high flexibility and elasticity also at low and very low temperatures. This makes the composition of the invention particularly suitable for use in all types of surfaces in contact with water, such as rain drains, sewage pipes, drains or tunnels, water barrier coverings under tiles in wetrooms, in swimmimg pools and other water tanks. The composition is also suitable as mending material for such coverings.

The invention is further illustrated by the folowing examples.

Examples

1. Materials:

- Trass powder from Meurin, Germany; particle size < 100 pm

- Brick powder: from Schafer Kalk, Germany; particle size < 250 pm; produced from discarded bricks and tiles

- CaO powder 1 from Schafer Kalk, Germany; Precal 30 N; particle size <90 pm

- CaO powder 2 from Schafer Kalk, Germany; Precal 641 ; particle size <90 pm

- Sand 1 ; F36; particle size 0.09-0.25 mm

- Sand 2; particle size 0.2-0.6 mm

- Rubber powder type K0002 from MRH (Muelsener Rohstoff- und Handelsgesellschaft mbH), particle size < 0.23 mm; produced from discarded tyres

- Rheovis® HS 1980; powdery thickener from BASF SE

- Acronal® 5400; from BASF SE; aqueous anionic copolymer dispersion of a copolymer of an acrylic acid ester and styrene; solids content: ca. 57%, Tg: -8°C; viscosity (250 s^-1 at 23°C; DIN EN ISO 3219): 50-350 mPa-s, pH 5.5-7.5.

- Acronal® 5442; from BASF SE; aqueous, self-cross-linking dispersion of a copolymer of an acrylic ester and styrene; solids content: ca. 52.5-54.5%; Tg: -15°C; viscosity: ca. 10-100 mPa-s, pH 5.5-8.5. - Acronal® 5028; from BASF SE; aqueous anionic copolymer dispersion of a copolymer of an acrylic acid ester and acrylonitrile; solids content: ca. 55%, Tg: -55°C; viscosity (250 s^-1 at 23°C; DIN EN ISO 3219): 40-180 mPa-s, pH 6.5-8.5.

- Acronal® 5311 ; from BASF SE; aqueous anionic copolymer dispersion of a copolymer of an acrylic acid ester and styrene; solids content: ca. 54%, Tg: -30°C; viscosity (250 s^-1 at 23°C; DIN EN ISO 3219): 50-300 mPa-s, pH 7-9.

- Vinnapas® 760 ED; from Wacker Chemie AG; aqueous copolymer dispersion of a copolymer of vinylacetate, ethylene and a vinylester of a long-chain saturate carboxylic acid; solids content: ca. 59%, Tg: -12°C; viscosity (250 s ¹ at 23°C; DIN EN ISO 3219): ca. 2000 mPa-s.

- Acronal® P5466; from BASF SE; spray dried powder of an aqueous anionic copolymer dispersion of a copolymer of an acrylic acid ester and styrene; dry matter content: > 99%; copolymer content > 85%; Tg: -15°C.

- Foamstar® SI2210: defoamer from BASF SE

- Dispex® AA 4135: sodium polyacrylate dispersant from BASF SE

- CEM I 52.5 N: a Portland cement type Milke of HeidelbergCement AG, Germany.

- Omyacarb 15 GU: limestone (calcium carbonate) powder from Omya

- Vinapor® DF 901 OF; defoamer based on fatty alkohol alkoxylate and polysiloxane; from BASF SE

- Fomaster® NO 2306: defoamer from BASF SE

- Istra 40: normal setting, rapid hardening/quick setting calcium aluminate cement with high early strength of Calucem GmbH, Mannheim, Germany.

- AHH: gypsum (a-semihydrate) for providing calcium ions

- Citric acid as retardant for the setting of Istra 40

- Li carbonate as accelerator for the setting of the CEM I 52.5 N/lstra 40 system

2. Compositions

2.1 Compositions according to the invention

Following composition of the invention were prepared by intimately mixing the ingredients in the below-indicated amounts. Compositions A and B are formulated separately. Composition 1 is composed of composition A1 and composition B1 , Composition 2 is composed of composition A2 and composition B2, and Composition 3 is composed of composition A3 and composition B3. Table 1

Table 1 (continued)

2.2 Comparative cementitious compositions Following comparative, cementitious composition were prepared by intimately mixing the ingredients in the amounts indicated in table 2. Compositions Comp-A and Comp-B are formulated separately. Composition Comp-1 is composed of composition Comp-A1 and composition Comp-B1 , Composition Comp-2 is composed of composition Comp- A2 and composition Comp-B2, and Composition Comp-3 is composed of composition Comp-A3 and composition Comp-B3. Table 2

3. Application tests 3.1 Flexibility - determination of crack bridging properties of the watertight coverings obtained from the inventive compositions at low temperatures

The crack bridging ability at low temperatures was tested according to DIN EN 14891 . For this purpose, the respective compositions A and B given in table 1 were thoroughly mixed. Analogously, the respective compositions Comp-A ad Comp-B given in table 2 were thoroughly mixed. Mixing will be done by a basket lab mixer for 2 min at a speed of 600 1/sec.

The obtained mixture was directly coated onto a mortar prism according to DIN EN 14891 A8. After coating of a very fine coat (scratch spatula) and drying (~ 20 min) the first waterproofing coating was applied (thickness 1 .2 mm wet). After drying (approx. 3h) a second layer was coated (thickness also 1 .2 mm wet). For each test formulation a preparation of three samples were done (3 samples for 23°C test 3 samples for -5°C test and 3 samples for -20°C test). According to DIN EN 14891 a drying of 28d at 23°C/50% r.H. followed. After drying period the samples was cracked in that way that only the substrate was cracked. The samples which are measured at -5°C and -20°C was stored for 4h in a climate chamber. Samples then were put in an elongation equipment and pulled apart without shearing at a defined rate according to EN 14891 until cracks are visible on the coating surface. The gap width at that point was measured and noted. The broader the gap width, the higher the flexibility Measurement at -5°C and -20°C was done complete in a climate chamber. The results are given as averages of 3 tests and compiled in table 3.

Table 3

1) complete cracking As can be seen, the water-tight coverings obtained from the compositions of the invention have superior flexibility and crack bridging properties at -20°C as compared to the water-tight coverings obtained from the prior art cementitious compositions.

3.2 Bond strength

The bond strength was measured according to DIN EN 14891 :2017. The samples were measured after storage at ambient conditions, after storage in water and after storage in chlorine water. a) Sample preparation

For this purpose, the respective compositions A and B given in table 1 were thoroughly mixed. Analogously, the respective compositions Comp-A ad Comp-B given in table 2 were thoroughly mixed.

The obtained mixture was directly coated onto mortar prism according to EN 12004- 2:2016 by first applying fine coat (scratch spatula) and drying (~ 20 min), secondly applying a first waterproofing coating (thickness 1 .2 mm wet) and after drying (approx. 3h) a second layer (thickness also 1 .2 mm wet). The thus allowed coating was allowed to set for 24h under ambient conditions. An adhesive coating was applied. After 5 min, 9 tiles of the type V1 according to EN 14411 :2016 were placed on the adhesive coating at a distance of 50 mm and pressed with a loading of 20 ± 0.05 N. b) Storage under ambient conditions (bond strength dry)

The samples obtained in a) were kept at ambient conditions for 27 days. Then, tie rod plates were glued to the tiles with a high-strength adhesive. After 28 days of overall storage, the bond strength was measured by applying a force with a constant rate of 250 ± N/s. c) Storage under water (bond strength wet)

The samples obtained in a) were stored in water of ambient temperature for 27 days. After drying, tie rod plates were glued and the bond strength was measured as described in b). d) Storage under chlorine water (bond strength chlorine water)

The samples obtained in a) were kept at ambient conditions for 28 days and then stored in chlorine water for 7 days. Chlorine water was prepared from 200 mg/l NaCI, 200 mg/l of Na2SC>4 and NaOCI kept at a concentration of 0.3 to 0.6 mg/l. The pH was kept at 6.5 to 7.8. After storage, the sample was rinsed with water and dried. After drying, tie rod plates were glued and the bond strength was measured as described in b). e) Storage under aqueous KOH (bond strength aq. KOH)

The samples obtained in a) were kept at ambient conditions for 28 days and then stored in 3% by weight aqueous solution of potassium hydroxide for 14 days. After storage, the sample was rinsed with water and dried. After drying, tie rod plates were glued and the bond strength was measured as described in b).

The results are compiled in Table 4.

Table 4

3.3 Water tightness

According to DIN EN 14891 A7 the water tightness was measured, but at a higher pressure of 2.5 bar. For this, concrete specimens were prepared as described in DIN EN 14891 A7 and kept at ambient conditions for 28 days. The 3 hardened specimens were coated on one surface as described in section 3.1 . Then the other surfaces were sealed. The specimens were weighed and was stored under water pressure of 2.5 bar for 7 days and then weighed again. The coating was considered water-tight, if the weight gain of the 3 specimens was on average less than 25 g. Compositions 1 , 2, 3, 7, 8, 9, 10 and 11 showed good water tightness of > 2.5 bar and low water absorption. 3.4 Mechanical Properties of the coatings

The mechanical properties of water-tight coverings obtained from the compositions of the invention were measured according to DIN EN 527-1 and -2. a) Sample preparation

For this purpose, the respective compositions A and B given in table 1 were thoroughly mixed whereby slurries were obtained which can be used for producing the water-tight coverings. Two welding wires with a diameter of 2.5 mm were placed on a Teflon- coated plate at a distance of approx. 10 cm and fixed with adhesive tape. The thus obtained slurries were applied to the gap with a knife spatula and then levelled over the welding wires with a trowel. The film thickness was thus 2.5 mm for wet application. After 24 hours, the dried films were removed from the substrate. The films were dried for another 6 days at 23°C/50% r.H.. Then 3 test specimens (dumb-bells S2) for dry storage and 3 test specimens (dumb-bells S2) for wet storage were cut from the films of the dried sealing slurry using a punch. b) Film properties after dry storage under ambient conditions

The samples obtained in a) were kept at ambient conditions (50% r.h. and 23°C) for 28 days. Mechanical properties were then determined by the protocol outlined in DIN EN 527-1 and -2. For this, the test specimens were clamped in the testing machine and pulled at a speed of 50 mm/min. The elongation and associated force were registered. The results are summarized in table 5. c) Film properties after storage under water (wet storage)

The samples obtained in a) were kept at ambient conditions for 6 days followed by storage in tap water for 21 days at 23°C. Mechanical properties were then determined by as outlined in b) above. The results are summarized in table 5.

Table 5:

3.5 Capillary water uptake a) Sample preparation

For this purpose, the respective compositions A and B given in table 1 were thoroughly mixed whereby slurries were obtained which can be used for producing the water-tight coverings. Two welding wires with a diameter of 2.5 mm were placed on a Teflon- coated plate at a distance of approx. 10 cm and fixed with adhesive tape. 300 g of the thus obtained slurries were applied to the gap with a knife spatula and then levelled over the welding wires with a trowel. The film thickness was thus 2.5 mm for wet application.

After 24 hours, the dried films were removed from the substrate. The films were dried for another 28 days at 23°C/50% r.H.. Then rectangular test specimens (5 cm x 10 cm) were cut from the films of the dried sealing slurry.

The weight of the films was determined on a laboratory balance. Then each film was placed in a shallow rectangular bowl of tap water so that the film was completely covered with water. The films were removed from the bowl at specific times, dabbed with an absorbent cloth and weighed again. The change in weight was determined and recorded. The results are given in % weight gain, based on the staring weight. The results are shown in Table 6.

Table 6:

Claims

36 Claims

1 . A composition for producing watertight coverings, which comprises

A a powdery composition A, where the powdery composition A comprises: a.1 a powdery pozzolanic material comprising a powdery natural poz- zolanic material in an amount of at least 30% by weight, based on the total amount of the pozzolanic material, a.2 powdery non-slaked lime, and a.3 at least one powdery aggregate; and

B a liquid composition B comprising an aqueous polymer dispersion made of polymerized ethylenically unsaturated monomers M or a powdery composition B comprising a polymer powder obtained from the aqueous polymer dispersion, where the polymer of the aqueous polymer dispersion has a glass transition temperature Tg of at most +15°C as determined by the differential scanning calorimetry (DSC) method according to

ISO 11357-2:2013, and e.g. in the range of -60 to +10°C, in particular in the range of -40 to 5°C, especially in the range of -30 to 0°C.

2. The composition of claim 1 , wherein the pozzolanic material comprises a powdery trass, in particular a powdery volcanic trass in an amount of at least 30% by weight of the total amount of the pozzolanic material.

3. The composition of claim 2, wherein the pozzolanic material additionally comprises brick powder.

4. The composition of claim 3, wherein the pozzolanic material comprises i. 50 to 90% by weight, based on the total amount of pozzolanic material, of powdery trass, in particular powdery volcanic trass; and

5. The composition of any one of the preceding claims, wherein the weight ratio of the pozzolanic material to the non-slaked lime is in the range of 2:1 to 5:1.

6. The composition of any one of the preceding claims, wherein the amount of the pozzolanic material is in the range of 30 to 65% by weight, based on the total weight of the powdery composition A. 37

7. The composition of any one of the preceding claims, wherein the amount of the non-slaked lime is in the range of 8 to 35% by weight, based on the total weight of the powdery composition A.

8. The composition of any one of the preceding claims, wherein the powdery aggregate comprises sand, in particular a combination of medium sand and fine sand.

9. The composition of any one of the preceding claims, wherein the powdery composition A additionally comprises an organic powdery recycling material, such as powdered rubber.

10. The composition of any one of the preceding claims, wherein the powdery composition A additionally comprises powdery kaolin.

11 . The composition of any one of the preceding claims, wherein the aqueous polymer dispersion is a self-crosslinking polymer dispersion.

12. The composition of any one of the preceding claims, wherein the aqueous polymer dispersion is selected from aqueous polymer dispersions of styrene-butadi- ene copolymers, aqueous polymer dispersions of vinylacetate ethylene copolymers and aqueous polymer dispersions of styrene-acrylate copolymers.

13. The composition of any one of the preceding claims, wherein the polymer of the polymer dispersion is made of ethylenically unsaturated monomers M, which comprise i. 80 to 99.9% by weight, based on the total amount of monomers M, of at least one monomer M1 , which is selected from a combination of at least one monovinylaromatic monomer M1a and at least one further monomer M1 b selected from conjugated aliphatic dienes, alkylesters of acrylic acid or methacrylic acid and cycloalkylesters of acrylic acid or methacrylic acid and mixtures thereof,

II. 0.1 to 15% by weight, based on the total amount of monomers M, of at least one monomer M2 selected from monoethylenically unsaturated neutral monomers having a solubility in water of at least 60 g/L at 20°C, and ill. optionally 0 to 5% by weight, based on the total amount of monomers M, of one or more monomers M3 which effect self-crosslinking of the polymer.

14. The composition of any one of the preceding claims, where the relative amount of the polymer of the aqueous polymer dispersion and the powdery composition A is in the range of 1 :10 to 1 :1 and in particular in the range of 1 :5 to 1 :1.

15. The composition of any one of the preceding claims, which additionally contains a polymeric dispersant.

16. The composition of any one of the preceding claims, where the composition is formulated as a two kits of part formulation of the powdery composition A as a first part of the formulation and the liquid composition B as a separately formulated second part of the formulation.

17. The composition of any one of claims 1 to 15, where the composition is formulated as a powdery formulation which is a mixture of the powdery components of the powdery composition A and the powdery composition B.

18. Use of the composition of any one of the preceding claims for providing watertight coverings.

19. A method for providing watertight coverings which comprises mixing the composition A, the polymer of the composition B and water and applying the liquid mixture to a surface, where a water-tight covering is required.