WO2010105979A1 - Polymer-modified cement - Google Patents

Abstract

The invention relates to a method for producing a particularly dry, polymer-modified, hydraulic, latent-hydraulic or pozzolanic setting construction chemical product by milling at least one vinyl polymer together with at least on hydraulic, latent-hydraulic or pozzolanic setting material or a mineral pre-product thereof, wherein the total volume of vinyl polymer equals 0.6 to 10 wt % based on the total weight of the hydraulic, latent-hydraulic or pozzolanic setting construction chemical product and the vinyl polymer is selected from the polymers based on vinyl acetate, acrylic acid and the derivatives thereof, styrene, ethylene, vinyl versatate, vinyl laurate, vinyl chloride or mixtures thereof, wherein homopolymers of the styrene and polymers comprising imidized acrylate units are removed. The invention further relates to a polymer-modified product that can be produced according to the method according to the invention and to the use thereof in concrete, tile adhesive, joint filler, spackle compounds, waterproofing slurry, mortar compounds and cement compounds. In addition, the invention also relates to a construction chemical composition comprising the construction chemical products that can be produced according to the invention.

Description

 Polymer modified cement

The present invention relates to a process for the preparation of a, in particular dry, polymer-modified hydraulic, latent-hydraulic or pozzolanic-setting construction chemical product. The invention further relates to a product mentioned above, which can be prepared by the process according to the invention, as well as its use in a construction chemical composition.

Polymer-modified hydraulic, latent-hydraulic or pozzolanic-setting building chemical products are already known from the prior art. For example, in tile adhesives cements are used, which are called dispersion or. Redispersionspulver be added. The dispersion or redispersion powders are finely divided polymer particles which form stable dispersions when water is added. These dispersion powders are generally prepared by spray-drying polymer dispersions. The dispersion powders provide in the tile adhesives mentioned above for better processability, in particular an improved application behavior and also provide after curing for a certain flexibility so that can be produced in this way flexible tile adhesive. However, it is sometimes considered disadvantageous in these dispersion powders that they are available only from a very limited number of different polymers and, moreover, are very expensive due to the complicated production.

There are already flexible tile adhesives in the form of 2-component products in which the dry ingredients such as cement, quartz sand, etc. are premixed in a first component and the second component is formed by an aqueous polymer dispersion which is included. The mixing of the tile adhesive is then carried out directly on site by mixing these two components in a predetermined mixing ratio. A disadvantage, however, in this solution that the handling of two components is cumbersome and further that the transport cost of such a product is significantly higher than that of dry products because of the inevitable co-transport of water in the polymer dispersion.

The object of the present invention is therefore to provide a polymer-modified hydraulic, latent-hydraulic or pozzolanic setting building chemical product, which can be used as a one-component product and is less expensive than the previously known products. In addition, the polymer-modified products should be able to be easily incorporated into more complex construction chemical preparations and give the latter superior application properties.

Surprisingly, it has been found that a polymer-modified end product is obtained by a process in which a selected vinyl polymer is ground in a predetermined amount together with a hydraulically, latently hydraulic or pozzolanic setting material or its mineral precursor, which is on the one hand much cheaper as a mixture with a dispersion powder, while at the same giving the product excellent processability properties and good post-curing properties, particularly in terms of flexural strength, compressive strength and shrinkage on curing. This method has the further advantage that hydraulically, latently-hydraulically or pozzolanically setting substances as a rule have to be subjected to a grinding process during production or refinement. In this grinding process, the polymer can then be added.

The grinding of a polymer with a hydraulic, latent-hydraulic or pozzolanic-setting substance or its mineral precursor is known in principle.

Thus, DE 200 17 460 U1 discloses a dry mix of curable thick materials containing a polystyrene granules, on the particle surfaces of which at least one hydraulic binder has been adhesively ground. The grinding is intended to prevent the light and voluminous polystyrene granules and the heavier and more compact binder from segregating during storage or further processing. Large volume fractions of polystyrene are milled with small volumes of binder, so that the resulting product must be considered as modified polystyrene. DE 200 17 460 U1 does not disclose that polymer-modified binders which have advantageous properties can be obtained by grinding certain vinyl polymers with a hydraulic, latent-hydraulic or pozzolanic-setting substance or its mineral precursor.

DE 696 31 885 T2 describes cements which contain imidized acrylic polymers of defined structure. These are polymers which have mandatory imidated acrylate units. By adding the special polymer in particular the flowability of the cement and the formation of air pores should be positively influenced. The addition of other polymers, such as esterified acrylate copolymers, is described as disadvantageous. As regards the preparation of the cement treated with imidated acrylic polymer, it is stated that this can be done at any stage of the formation or use of the cement. One possibility mentioned is the mixing of the polymer in the cement factory with clinker cement raw material during its grinding to form cement powder, without, however, mentioning any advantages of this procedure. But also the classical addition of the polymer as part of the hydration water is possible. From DE 696 31 885 T2 it is therefore impossible to find any indications that polymer-modified binders having advantageous properties can be obtained by grinding a polymer with a hydraulic, latent-hydraulic or pozzolanic-setting substance or its mineral precursor.

Finally, from DE 600 16 610 T2 the addition of various polymers in the grinding of cement clinker known. However, the polymers are added here in small quantities and serve to improve the milling process. A specific modification of the milled cement is neither intended nor mentioned.

A first subject of the present invention is therefore a process for the preparation of a, in particular dry, polymer-modified hydraulic, latent-hydraulic or pozzolanic-setting building chemical product by grinding at least one vinyl polymer together with at least one hydraulic, latent hydraulic or pozzolanic setting substance or its mineral precursor, wherein the total amount of vinyl polymer from 0.6 to 10 wt .-%, based on the total weight of the hydraulic, latent-hydraulic or pozzolanic and the vinyl polymer is selected from the polymers based on vinyl acetate, acrylic acid and their derivatives, styrene, ethylene, vinyl versatate, vinyl laurate, vinyl chloride, or mixtures of these, homopolymers of styrene, as well as polymers that imidized Acrylate units contain, are excluded.

Hydraulic, latent-hydraulic or pozzolanic-setting substances are known in the art. For the purposes of the present invention, a mineral precursor is understood as meaning, for example, the coarse-grained or ballast-like precursor which is converted into the hydraulic, latent-hydraulic or pozzolanic-setting substance by grinding, for example in a ball mill, high-bed roller mill or vertical roller mill. Such a mineral precursor can be, for example, Portland cement clinker, which is ground in a cement mill with calcium sulfate to cement.

In the method according to the invention, the procedure is such that the vinyl polymer is ground together with the hydraulic, latent-hydraulic or pozzolanic-setting substance or its mineral precursor in a mill, for example in a ball mill.

In addition to the abovementioned advantages, the process according to the invention also has the further advantage that a particularly dry, polymer-modified construction chemical product can be prepared in which not only the relatively small selection of polymers to which dispersion powders are obtainable can be used. but in principle all vinyl polymers, since the inventive method is not limited by the fact that can be made of certain vinyl polymers no redispersible powders. For this reason can be produced with very highly customized properties with the inventive method crop products.

For the purposes of the present invention, a dry chemical product is understood as meaning a product which, apart from any water of crystallization and residual moisture possibly contained in the pulverulent constituents, contains no water in liquid form, as is the case, for example, in the above-mentioned two-part method known from the prior art. Component tile adhesives is known in which a component is provided by an aqueous polymer dispersion. A dry product is therefore understood to mean in particular a product which has a residual moisture content of up to 5% by weight of water, preferably of up to 2.5% by weight of water, very particularly preferably up to 1% by weight of water, in each case based on the total weight of the polymer-modified hydraulic, latent-hydraulic or pozzolanic-setting building chemical product.

A further advantage of the method according to the invention is that the polymer-modified construction chemical products produced by this process have improved mechanical properties after mixing with water and subsequent curing compared to a product in which the same polymer in the form of a liquid dispersion to the same hydraulic, latent-hydraulic or pozzolanic binder was given. Also in comparison to construction chemical products in which the relatively expensive dispersion powder are used, the polymer-modified construction chemical products according to the invention show very good properties in terms of their processability and final strength.

According to the invention, the vinyl polymer (s) is used in an amount of at least 0.6% by weight, based on the total weight of the hydraulic, latent-hydraulic or pozzolanic-setting building chemical product. As a result, corresponding building chemical products are obtained, which have excellent properties, in particular in terms of processability, shrinkage during curing and the flexural and compressive strength of the cured product. Preferably, the total amount of vinyl polymer, based on the total weight of the hydraulic, latent-hydraulic or pozzolanic-setting construction chemical product, at least 0.7 wt .-%, preferably at least 1% by weight, particularly preferably at least 2 wt .-% and most preferably at least 2.5 wt .-%. The maximum total amount is preferably 9% by weight, more preferably 8% by weight and most preferably 7% by weight.

The vinyl polymer is more preferably used in a total amount, based on the total weight of the hydraulic, latent-hydraulic or pozzolanic-setting construction chemical product, of from 0.7 to 9% by weight, preferably from 1 to 8% by weight, more preferably 2 to 7 wt .-% and most preferably 2.5 to 7 wt .-%, used.

These polymer contents are particularly preferred because when the vinyl polymers are used in the stated amounts, polymer-modified products can be produced which can be further processed into more complex construction chemical compositions, such as concrete, tile adhesives and the like, which then require no further addition of polymers To achieve flexibility or good processability.

The total amount of vinyl polymer is understood to be the sum of the amount of all vinyl polymers in the event that several vinyl polymers are used.

Preferably, the method according to the invention comprises at least the steps:

a) filling at least one hydraulic, latent-hydraulic or pozzolanic-setting substance or its mineral precursor into a mill; b) starting the milling process; c) adding at least one of said vinyl polymers in the amount provided according to the invention during the milling process. This process procedure is particularly advantageous because hydraulically, latently-hydraulically or pozzolanically setting substances and / or its mineral precursors are frequently subjected to a grinding process in which the polymers can be easily metered. A complex conversion of production facilities is therefore not mandatory.

Preferably used as hydraulic, latent-hydraulic or pozzolanic setting material is ground Portland cement clinker (K), ground blastfurnace slag (S), ground fly ash (V, W), ground pozzolana (P, Q), ground burnt slate, ground limestone (L, LL ), Silica fume (D), ground calcium sulfate or mixtures thereof. The names in brackets refer to the definitions according to EN 197-1.

Portland cement clinker (K), blastfurnace slag (S), fly ash (V, W), pozzolans (P, Q), burned slate, limestone (L, LL), calcium sulfate is preferably used as the mineral precursor of the hydraulically, latently hydraulic or pozzolanic setting substance used in coarse or granulated form or mixtures of these.

Mixtures are understood to mean in each case a mixture of two of the stated components, but also of 3, 4 or more of the stated components, mixtures of the hydraulic, latent-hydraulic or pozzolanic-setting substances with one another, of the mineral precursors with one another, but also mixtures of at least one hydraulically , latent-hydraulic or pozzolanic-setting substance with at least one mineral precursor of a hydraulic, latent-hydraulic or pozzolanic setting material can be used.

According to the invention, the vinyl polymers used are selected from the polymers based on vinyl acetate, acrylic acid and derivatives thereof, styrene, ethylene, vinyl versatate, vinyl laurate, vinyl chloride, or mixtures of these, homopolymers of styrene, as well as polymers containing imidated acrylate units, with exception of. Derivatives of acrylic acid are understood as meaning the following compounds: alkali metal and ammonium salts of acrylic acid, methacrylic acid and their alkali metal and ammonium salts, and the C 1 -C 30 -alkyl esters of acrylic and methacrylic acid. Particularly preferred acrylic acid derivatives are methyl methacrylate, ethyl methacrylate and butyl acrylate.

The vinyl polymers used are preferably selected from homopolymers of vinyl acetate, of acrylic acid, of methacrylic acid, of C 1 -C 6 -alkyl acrylate and of C 1 -C 8 -alkyl methacrylate, and of copolymers of styrene-acrylate, vinyl acetate-ethylene, vinyl acetate-vinyl versatate, Vinyl acetate-ethylene-vinyl versatate, vinyl acetate-ethylene-methyl methacrylate, vinyl acetate-ethylene-vinyl laurate, vinyl acetate-acrylate-vinyl versatate, vinyl acetate-acrylate-vinyl versatate-ethylene, vinyl chloride-ethylene-vinyl laurate, vinyl chloride-ethylene-acrylate, vinyl chloride-ethylene-vinyl acetate, Butyl acrylate vinyl acetate vinyl versatate, or mixtures of these.

The vinyl polymers used are particularly preferably selected from the copolymers styrene-acrylate, vinyl acetate-ethylene, vinyl acetate-vinyl versatate, vinyl acetate-ethylene-vinyl versatate, vinyl acetate-ethylene-methyl methacrylate, vinyl acetate-ethylene-vinyl laurate, vinyl acetate-acrylate-vinyl versatate, vinyl acetate. Acrylate vinyl versatate ethylene, vinyl chloride ethylene vinyl laurate, vinyl chloride ethylene acrylate, vinyl chloride ethylene vinyl acetate, butyl acrylate vinyl acetate vinyl versatate, or mixtures of these.

Accordingly, polymer-modified construction-chemical products, in particular dry polymer-modified construction-chemical products, which can contain a very wide selection of polymers or copolymers, can be prepared by the process according to the invention. Therefore, there is no limitation on the construction chemical products of the present invention as in the case of mixtures containing dispersion powders which are available only from a very limited range of polymers. Due to the large number of usable polymers and copolymers building chemical products can be produced with the aid of the method according to the invention, whose properties are very individual to the requirements the purpose of use can be adjusted. This is only possible to a very limited extent with the aid of dispersion powders.

The vinyl polymer can be used, for example, in the form of a powder, granules or a dispersion. It is preferably used in the form of an aqueous dispersion. The use of dispersions has the advantage that they can be simply and accurately added during the grinding process. The liquid contained in the dispersions, such as water, evaporates predominantly during the continuous grinding process in the mill, since the mill temperature is typically in the range of 120 to 140 ⁰ C. The use of powders or granules offers the advantage that they are very inexpensive and, moreover, that they do not introduce any further substances which are frequently present in polymer dispersions, for example surfactants.

Another advantage of the resulting high temperatures due to frictional heat during the grinding process is that the vinyl polymers can be added to the milling process not only in the form of a dispersion but also, for example, as a solid in the form of powders or granules. As a result of the higher temperatures, the polymer powders or granules soften or melt slightly and are thus distributed over the mineral constituents. It has also been found that by the grinding process, a change to the polymers can be made, in particular in relation to the fact that the grinding process can lead to a polymer chain degradation due to the mechanical and thermal effect of the mill. This is more pronounced in particular for longer grinding times and high mill temperatures, such as above 135 ⁰ C. This effect can also be used advantageously to adapt the properties of the construction chemical product obtainable by the process to the requirements. For this purpose, the skilled person can set the desired product parameters based on a few experiments with the milling time and the mill temperature. The mill temperature can be in the range between 80 and 160 ⁰ C. The milling time or average residence time of the mill is typically between 10 and 60 minutes after the addition of the vinyl polymers. Preferably, a polymer dispersion is used which has a solids content of 20 to 70 wt .-%, preferably 30 to 65 wt .-%, particularly preferably 40 to 60 wt .-%.

Preferably, the vinyl polymer used has a molecular weight of 50,000 to 500,000, in particular 75,000 to 400,000, most preferably 100,000 to 300,000. The molecular weights given are the respective number average M _n which, as is familiar to the person skilled in the art, is determined by gel permeation chromatography (GPC).

In the context of the process according to the invention, it is likewise possible for further secondary constituents to be added during the preparation of the polymer-modified hydraulic, latent-hydraulic or pozzolanic-settling chemical construction product. These may be per se known cement additives, such as grinding aids or chromate reducers.

A further subject of the present invention is a polymer-modified hydraulic, latent-hydraulic or pozzolanic-setting product which can be prepared by the process according to the invention. Such a polymer-modified product is preferably a dry product. For the purposes of this embodiment, a dry product is understood as meaning a product which has a residual moisture content of up to 5% by weight of water, preferably of up to 2.5% by weight of water, very particularly preferably up to 1% by weight of water , in each case based on the total weight of the polymer-modified hydraulic, latent-hydraulic or pozzolanic setting building chemical product. The products which can be produced by the process according to the invention have the advantages over the products known from the prior art that, on the one hand, one-component dry chemical compositions such as tile adhesives and the like can be produced therefrom, in which the user merely has to add water. Furthermore, in the production of concrete or tile adhesive can be dispensed with the use of relatively expensive dispersion powder. Finally, that opens Process according to the invention the preparation of polymer-modified construction chemical products which can be modified by means of polymers which are not obtainable as dispersion powder. In addition, there is a further advantage in that, with the aid of the control of the grinding process, in particular with regard to the duration of the milling process and the mill temperature, the polymer-modified products can be specifically adapted to the requirements of the later intended use.

According to a preferred embodiment of the invention the polymer-modified hydraulic, latent-hydraulic or pozzolanic setting product, the vinyl polymer in this product, a minimum film-forming temperature (MFT) in accordance with ISO 2115, DIN 53787 of up to 35 ⁰ C, preferably of up to 20 ⁰ C, particularly preferably up to 10 ^° C., very particularly preferably up to 5 ^° C. This is particularly advantageous because in this way polymer-modified products can be created which contain vinyl polymers which have film-forming properties at the usual processing temperatures and thus have a positive influence on the processing properties.

Another object of the present invention is a hydraulic, latent hydraulic or pozzolanic setting building chemical composition, in particular concrete, such as transport, construction site or ready-mixed concrete, tile adhesives, joint fillers, fillers, sealing slurries, mortar, cement and the like, which is a polymer-modified hydraulic, latent hydraulic or pozzolanic-setting building chemical product which can be prepared by the process according to the invention.

According to a preferred embodiment of the hydraulic, latent-hydraulic or pozzolanic-setting building chemical composition according to the invention, this additionally contains dispersion powder.

Another object of the present invention is the use of a polymer-modified hydraulic, latent-hydraulic or pozzolanic setting building chemical product which can be prepared by the novel process is, in concrete, in particular transport, construction site or ready-mixed concrete, in tile adhesives, joint fillers, fillers, sealing slurries, mortar compounds, cement compounds and the like.

The present invention will now be explained in more detail with reference to some embodiments, which serve only for illustration and are not to be understood as limiting the general inventive concept.

Examples

Unless otherwise indicated, all parts and percentages are by weight.

Preparation of a polymer-modified cement according to the invention:

In a ball mill Portland cement clinker, calcium sulfate and cement additives are supplied in the form of a constant mass flow for grinding. During the grinding process Acronal S 400 (aqueous anionic copolymer dispersion of an acrylic ester and styrene, polymer content about 57 wt .-%, manufacturer BASF) is supplied at a mill temperature of about 140 ° C in an amount that the resulting polymer-modified product 3 wt. -% polymer content. The milling is now carried out at a mean residence time of about 60 minutes and a Matehalaustragstemperatur from the mill of 130 ⁰ C. The product is dry after this grinding time and has a residual moisture content of 0.3 wt .-%.

In an analogous manner, a 6 wt .-% polymer modified cement by metering of Vinnapas EP 64 (aqueous copolymer dispersion of vinyl acetate and ethylene, polymer content about 55 wt .-%, manufacturer Wacker) produced during the grinding process.

For comparison, a sample of the same cement is also taken, which was ground over the same period, but no polymer was added during the grinding process.

For the evaluation of the product properties, tile adhesives with the standard tile adhesive formulation according to Table 1 were prepared from these products: Table 1: Composition of dry mortar in g per 1000 g of dry mortar

^* : based on the polymer content; Acronal S 400 is added after grinding.

The test results with these tile adhesives are summarized in the following Table 2, wherein the mixing water amount for all systems is 230 g / kg dry mortar.

Table 2: Fresh and solid mortar properties of the products

These results show that the tile adhesive formulations comprising the polymer-modified cement according to the invention clearly surpass a formulation in which the corresponding amount of polymer has been added in the form of a liquid dispersion and a corresponding polymer-free formulation in terms of flexural strength, compressive strength and also in terms of deflection are.

Claims

claims Anspruch [en] A process for producing a polymer-modified hydraulic, latent-hydraulic or pozzolanic building-chemical product by grinding at least one vinyl polymer together with at least one hydraulic, latent-hydraulic or pozzolanic-setting substance or its mineral precursor, characterized in that the total amount of vinyl polymer O, 6 to 10 wt .-%, based on the total weight of the hydraulic, latent-hydraulic or pozzolanic setting building chemical product, and the vinyl polymer is selected from the polymers based on vinyl acetate, acrylic acid and derivatives thereof, styrene, ethylene, Vinyl versatate, vinyl laurate, vinyl chloride, or mixtures thereof, excluding homopolymers of styrene, as well as polymers containing imidated acrylate units. 2. The method according to claim 1, characterized in that it comprises at least the following steps: a) filling the at least one hydraulic, latent hydraulic or pozzolanic setting substance or its mineral precursor into a mill; b) starting the milling process; c) adding the at least one vinyl polymer during the milling process. 3. The method according to at least one of claims 1 to 2, characterized in that as a hydraulic, latent-hydraulic or pozzolanic setting material ground Portland cement clinker, ground blastfurnace slag, ground fly ash, ground pozzolans, ground burned slate, ground limestone, silica dust, ground calcium sulfate or Mixtures of these is used. 4. The method according to at least one of the preceding claims, characterized in that is used as a mineral precursor of the hydraulic, latent hydraulic or pozzolanic setting substance Portland cement clinker, blastfurnace, fly ash, pozzolans, burned slate, limestone, calcium sulfate in coarse or granular form or mixtures thereof , 5. The method according to at least one of the preceding claims, characterized in that the vinyl polymer is selected from homopolymers of vinyl acetate, acrylic acid, methacrylic acid, acrylic acid esters and methacrylic acid esters, and the copolymers styrene-acrylate, vinyl acetate-ethylene, vinyl acetate Vinyl versatate, vinyl acetate-ethylene-vinyl versatate, vinyl acetate-ethylene-methyl methacrylate, vinyl acetate-ethylene-vinyl laurate, vinyl acetate-acrylate-vinyl versatate, vinyl acetate-acrylate-vinyl versatate-ethylene, vinyl chloride-ethylene-vinyl laurate, vinyl chloride-ethylene-acrylate, vinyl chloride-ethylene Vinyl acetate, butyl acrylate vinyl acetate vinyl versatate, or mixtures of these. 6. The method according to at least one of the preceding claims, characterized in that the vinyl polymer is used in the form of a powder, granules or a dispersion. 7. The method according to at least one of the preceding claims, characterized in that the vinyl polymer is used in the form of a dispersion, and the polymer dispersion has a solids content of 20 to 70 wt .-%. 8. The method according to at least one of the preceding claims, characterized in that the total amount of vinyl polymer 0.7 to 9 wt .-%, preferably 1 to 8 wt .-%, particularly preferably 2 to 7 wt .-% and completely particularly preferably from 2.5 to 7% by weight, based in each case on the total weight of the hydraulic, latent-hydraulic or pozzolanic-setting building chemical product. 9. The method according to at least one of the preceding claims, characterized in that the vinyl polymer used has a molecular weight of 50,000 to 500,000. 10. Polymer-modified hydraulic, latent-hydraulic or pozzolanic-setting product, producible according to one of the preceding claims. 11. A polymer-modified hydraulic, latent-hydraulic or pozzolanic setting product according to claim 10, characterized in that the vinyl polymer in the product has a minimum film-forming temperature (MFT) according to ISO 2115, DIN 53787 of <35 ⁰ C. 12. Hydraulic, latent-hydraulic or pozzolanic setting building chemical composition comprising a hydraulic, latent-hydraulic or pozzolanic setting building chemical product according to claim 10 or 11. 13. Use of a polymer-modified hydraulic, latent-hydraulic or pozzolanic setting building chemical product according to claim 10 or 11 in concrete, tile adhesives, joint fillers, fillers, sealing slurries, mortar compounds or cement compounds.