EP1725507A2

EP1725507A2 - Use of polymer powder compositions that can be redispersed in water for loam construction materials

Info

Publication number: EP1725507A2
Application number: EP05715922A
Authority: EP
Inventors: Hermann Lutz; Alois Sommerauer; Klaus Bonin
Original assignee: Wacker Polymer Systems GmbH and Co KG
Current assignee: Wacker Polymer Systems GmbH and Co KG
Priority date: 2004-03-18
Filing date: 2005-03-10
Publication date: 2006-11-29
Also published as: WO2005092816A3; IN2014CN04829A; CN1934051A; WO2005092816A2; DE102004013468A1; CN100497235C

Abstract

The invention relates to the use of polymer powder compositions in loam construction materials. Said compositions can be redispersed in water, are devoid of emulsifiers and contain one or more film-forming polymers, one or more protective colloids, in addition to optional anti-caking agents.

Description

Use of polymer powder compositions redispersible in water in building materials

The invention relates to the use of water-redispersible polymer powder compositions containing one or more film-forming polymers, one or more protective colloids and, where appropriate, antiblocking agents in clay building materials, in particular clay dry mortars.

Earth building materials have been used as building materials for many centuries, especially for building houses. Loam is not a standardized building material and has a different composition depending on the place of discovery, which is generally a mixture of clay, silt (fine sand) and sand, which can also contain coarser components such as gravel, crushed stone or stones, and their proportion of clay is about 10 to 30% by weight. The advantages of earth building materials are their easy availability, simple processing, their high moisture storage effect (pleasant indoor climate) and their ecological advantages (reusability).

Building materials based on clay are therefore increasingly used today in the form of wet mortars, but increasingly also in the form of dry mortars in interior construction, e.g. used for plastering the walls (basic and decorative plasters) but also in connection with wooden constructions as filler material, or as adobe and wall paints. Other areas of application of earth building materials are soil sealing, for example in landfills, and in dam construction.

Disadvantages of earth building materials, however, are their low mechanical resilience (low strength, i.e. internal cohesion), their sensitivity to water and moisture (unstable to water), and their poor adhesion to various types of building substrates (poor adhesion). From DE-A 19800784 it is known to improve the abrasion resistance of clay plaster by adding cellulose binders. DE-U 20008006 describes the improvement of the abrasion resistance of plaster mortars based on clay using proteins as an additional binder. WO-A 00/68162 describes the addition of polysulfide-free, emulsifier-containing polymer preparations to building materials based on clay or clay.

The object of the invention was to improve the mechanical strength and water resistance of earth building materials, in particular dry clay mortars. In addition, the processability of the earth building materials should remain guaranteed.

The invention relates to the use of water-redispersible, emulsifier-free polymer powder compositions containing one or more film-forming polymers, one or more protective colloids and, where appropriate, anti-blocking agents in clay building materials.

Suitable film-forming polymers are those based on one or more monomers from the group comprising vinyl esters, (meth) acrylic esters, vinyl aromatics, olefins, 1,3-dienes and vinyl halides and optionally other monomers copolymerizable therewith.

Suitable vinyl esters are those of carboxylic acids with 1 to 12 carbon atoms. Vinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate, vinyl laurate, 1-methylvinyl acetate, vinyl pivalate and vinyl esters of α-branched monocarboxylic acids with 9 to 11 carbon atoms, for example VeoVa9 ^R or VeoVal0 ^R (trade names from Shell). Vinyl acetate is particularly preferred.

Suitable monomers from the group of acrylic acid esters or methacrylic acid esters are esters of unbranched or branched alcohols having 1 to 15 carbon atoms. Preferred methacrylic acid esters or acrylic acid esters are methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, pro- pyl methacrylate, n-butyl acrylate, n-butyl methacrylate, t-butyl acrylate, t-butyl methacrylate, 2-ethylhexyl acrylate. Methyl acrylate, methyl methacrylate, n-butyl acrylate, t-butyl acrylate and 2-ethylhexyl acrylate are particularly preferred.

Styrene, methylstyrene and vinyltoluene are preferred as vinyl aromatics. The preferred vinyl halide is vinyl chloride. The preferred olefins are ethylene, propylene and the preferred dienes are 1,3-butadiene and isoprene.

If necessary, 0.1 to 5% by weight, based on the total weight of the monomer mixture, of auxiliary monomers can also be copolymerized. 0.5 to 2.5% by weight of auxiliary monomers are preferably used. Examples of auxiliary monomers are ethylenically unsaturated mono- and dicarboxylic acids, preferably acrylic acid, methacrylic acid, fumaric acid and maleic acid; ethylenically unsaturated carboxamides and nitriles, preferably acrylamide and acrylonitrile; Mono- and diesters of fumaric acid and maleic acid such as the diethyl and diisopropyl esters and maleic anhydride, ethylenically unsaturated sulfonic acids or their salts, preferably vinylsulfonic acid, 2-acrylamido-2-methyl-propanesulfonic acid. Further examples are pre-crosslinking comonomers such as polyethylenically unsaturated comonomers, for example divinyl adipate, diallyl maleate, allyl methacrylate or triallyl cyanurate, or post-crosslinking comonomers, for example acrylamidoglycolic acid (AGA), methyl acrylamide methyl NMA (methylolamide), (MAGMEamide), Methylol methacrylamide, N-methyl olallyl carbamate, alkyl ethers such as the isobutoxy ether or ester of N-methylol acrylamide, N-methylol methacrylamide and N-methylolallyl carbamate. Epoxy-functional comonomers such as glycidyl methacrylate and glycidyl acrylate are also suitable. Further examples are silicon-ciumfunktionelle comonomers such as acryloxypropyltri (alkoxy) - and methacryloxypropyltri (alkoxy) silanes, vinyltrialkoxysilanes and vinylmethyldialkoxysilanes, with alkoxy groups at ^¬ example as ethoxy and ethoxypropylene glycol ether radicals can be contained. Monomers with hydroxyl or CO groups, for example methacrylic acid and acrylic acid, may also be mentioned. rehydroxyalkyl esters such as hydroxyethyl, hydroxypropyl or hydroxybutyl acrylate or methacrylate, and compounds such as diacetone acrylamide and acetylacetoxyethyl acrylate or methacrylate.

The monomers or the choice of the weight fractions of the comonomers is made in such a way that transition temperature is in general a glass ^¬ Tg of <40 ° C, preferably -10 ° C to + 25 ° C results. The glass transition temperature Tg of the polymers can be determined in a known manner by means of differential scanning calorimetry (DSC). The Tg can also be roughly predicted using the Fox equation. According to Fox TG, Bull. Am. Physics Soc. 1, 3, page 123 (1956) applies: 1 / Tg = xl / Tgl + x2 / Tg2 + ... + xn / Tgn, where xn stands for the mass fraction (% by weight / 100) of the monomer n, and Tgn is the glass transition temperature ^¬ in Kelvin of the homopolymer of the monomer n. Tg values for homopolymers are listed in Polymer Handbook 2nd Edition, J. Wiley & Sons, New York (1975).

Homopolymers or copolymers which contain one or more monomers from the group consisting of vinyl acetate, vinyl esters of α-branched monocarboxylic acids having 9 to 11 carbon atoms, vinyl chloride, ethylene, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, n -Butyl acrylate, n-butyl methacrylate, 2-ethylhexyl acrylate, styrene included. Copolymers with vinyl acetate and ethylene are particularly preferred; with vinyl acetate, ethylene and a vinyl ester of α-branched monocarboxylic acids with 9 to 11 carbon atoms; with n-butyl acrylate and 2-ethylhexyl acrylate and / or methyl methacrylate; with styrene and one or more monomers from the group of methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate; with vinyl acetate and one or more monomers from the group consisting of methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate and optionally ethylene; with 1,3-butadiene and styrene and / or methyl methacrylate and optionally further acrylic acid esters; where the mixtures mentioned may optionally contain one or more of the abovementioned auxiliary monomers. Most preferred are polymers of the abovementioned compositions which still contain 0.1 to 5% by weight, based on the total weight of the polymer, of monomer units which are derived from one or more comonomers from the group comprising ethylenically unsaturated mono- and dicarboxylic acids, such as Acrylic acid, methacrylic acid, fumaric acid and maleic acid; ethylenically unsaturated carboxamides and nitriles such as acrylamide and acrylonitrile; Monoesters of fumaric acid and maleic acid, as well as maleic anhydride, ethylenically unsaturated sulfonic acids or their salts, preferably vinylsulfonic acid, 2-acrylamido-2-methyl-propanesulfonic acid.

The film-forming polymers are prepared by the emulsion polymerization process or by the suspension polymerization process in the presence of protective colloids, preferably by the emulsion polymerization process, the polymerization temperature generally being 40 ° C. to 100 ° C., preferably 60 ° C. to 90 ° C., and at the copolymerization of gaseous comonomers such as ethylene can also be carried out under pressure, generally between 5 bar and 100 bar. The polymerization is initiated using the water-soluble or monomer-soluble initiators or redox initiator combinations which are customary for emulsion polymerization or suspension polymerization. Examples of water-soluble initiators are sodium persulfate, hydrogen peroxide and azobisisobutyronitrile. Examples of monomer-soluble initiators are dicetyl peroxydicarbonate, dicyclohexyl peroxydicarbonate, dibenzoyl peroxide. The initiators mentioned are generally used in an amount of 0.01 to 0.5% by weight, based on the total weight of the monomers. Combinations of the initiators mentioned in combination with reducing agents are used as redox initiators. Suitable reducing agents are, for example, sodium sulfite, sodium hydroxymethanesulfinate and ascorbic acid. The amount of reducing agent is preferably 0.01 to 0.5% by weight, based on the total weight of the monomers. To control the molecular weight, regulating substances can be used during the polymerization. If regulators are used, they are usually used in amounts of between 0.01 and 5.0% by weight, based on the monomers to be polymerized, and are metered in separately or premixed with reaction components. Examples of such substances are n-dodecyl mercaptan, tert. -Dodecyl mercaptan, mercaptopropionic acid, mercaptopropionic acid methyl ester, isopropanol and acetaldehyde. No regulating substances are preferably used.

Suitable protective colloids are partially saponified or fully saponified polyvinyl alcohols; polyvinylpyrrolidones; polyvinyl; Polysaccharides in water-soluble form such as starches (amylose and amylopectin), celluloses and their carboxymethyl, methyl, hydroxyethyl, hydroxypropyl derivatives; Proteins such as casein or caseinate, soy protein, gelatin; lignin; synthetic polymers such as poly (meth) acrylic acid, copolymers of (meth) acrylates with carboxyl-functional comonomer units, poly (meth) acrylamide, polyvinylsulfonic acids and their water-soluble copolymers; Melamine formaldehyde sulfonates, naphthalene formaldehyde sulfonates, styrene maleic acid and vinyl ether maleic acid copolymers. Partially saponified or fully saponified polyvinyl alcohols are preferred. Partially saponified polyvinyl alcohols with a degree of hydrolysis of 80 to 95 mol% and a Höppler viscosity in 4% aqueous solution of 1 to 30 mPas are particularly preferred (Höppler method at 20 ° C., DIN 53015).

After the end of the polymerization, postpolymerization can be carried out using known methods to remove residual monomers, for example by postpolymerization initiated with a redox catalyst. Volatile residual monomers can also be removed by distillation, preferably under reduced pressure, and, if appropriate, with the passage or passage of inert entraining gases such as air, nitrogen or water vapor. The aqueous dispersions thus obtainable have a solids content of 30 to 75% by weight, preferably 50 to 60% by weight. To prepare the water-redispersible polymer powder compositions, the dispersions are dried, if appropriate after the addition of protective colloids as a spraying aid, for example by means of fluidized-bed drying, freeze drying or spray drying. The dispersions are preferably spray dried. Spray drying is carried out in conventional spray drying systems, and atomization can be carried out by means of single-, two- or multi-component nozzles or with a rotating disc. The outlet temperature is generally selected in the range from 45 ° C. to 120 ° C., preferably 60 ° C. to 90 ° C., depending on the system, the Tg of the resin and the desired degree of drying. The viscosity of the food to be consumed is adjusted via the solids content in such a way that a value of <500 mPas (Brookfield viscosity at 20 revolutions and 23 ° C.), preferably <250 mPas, is obtained. The solids content of the dispersion to be evaporated is> 35%, preferably> 40%.

As a rule, the spray aid is used in a total amount of 0.5 to 30% by weight, based on the polymeric constituents of the dispersion. This means that the total amount of protective colloid before the drying process should be at least 1 to 30% by weight, based on the polymer content; 5 to 20% by weight, based on the polymer content, are preferably used.

Suitable protective aids are, for example, the protective colloids already mentioned. No other protective colloids are preferably used as polyvinyl alcohols as a spray aid.

A content of up to 1.5% by weight of antifoam, based on the base polymer, has often been found to be favorable during the spraying. To increase the shelf life by improving the blocking stability, particularly in the case of powders with a low glass transition temperature, the powder obtained can be equipped with an antiblocking agent (antibacking agent), preferably 1 to 30% by weight, based on the total weight of polymeric constituents. Examples of antiblocking agents are calcium carbonate or magnesium carbonate, talc, gypsum, silica, kaolins such as metakaolin, silicates with particle sizes preferably in the range from 10 nm to 10 μm.

For hydrophobic finishing, one or more hydrophobizing agents from the group comprising fatty acids and fatty acid derivatives and organosilicon compounds can be added to them before the dispersions are dried. Suitable compounds for this are listed, for example, in DE-A 10323205.

The clay building materials modified according to the invention are suitable for use as clay base plasters, clay decor plasters and clay paints, preferably for interior walls and ceilings, but also for exterior walls and damp rooms; as a clay mortar for laying clay bricks, for example to fill out timber frameworks, as a clay filler for floors / walls / ceilings; and as clay building adhesives. The clay building materials modified according to the invention are also advantageous in the production of clay moldings in order to impart greater resistance and strength to them, for example for clay / clay figures, clay / clay bricks, extruded clay moldings.

Surprisingly, coating the clay mortar with dispersion powders results in an extreme increase in the mechanical strength values (bending tensile strength, compressive strength, adhesion), which go far beyond what is known in other building material systems and mortars based on cement, gypsum or calhydrate. When using dispersion powders with a hydrophobic effect, it is surprisingly not only possible to massively reduce water absorption, but also to achieve very good water and moisture resistance, so that such products are also suitable for outdoor use.

The following examples serve to explain the invention further: The following redispersion powder compositions were used:

Redispersion powder 1: vinyl acetate-ethylene copolymer with Tg = 18 ° C 12% by weight polyvinyl alcohol 15% by weight antiblocking agent

Redispersion powder 2: vinyl acetate, ethylene VeoValO terpolymer with Tg = 5 ° C 12% by weight polyvinyl alcohol 15% by weight antiblocking agent

The redispersion powders were tested in the following clay formulation:

350.0 parts by weight of clay dry powder 70.0 parts by weight of quartz sand HR (0.1 - 1.2 mm) 250.0 parts by weight of quartz sand HR (0.2 - 0.7 mm) 300.0 parts by weight of quartz sand 81T (0.1 - 0.4 mm) 0.5 parts by weight modified bentonite (Optibent CP) 0.3 parts by weight cellulose ether (Walocel MKX 6000 PF50L) 1.5 parts by weight flax fiber F 513/6 X parts by weight redispersible powder

Testing the adhesive tensile strength:

To check the adhesion to the subsoil, the clay mortar was applied to clay bricks using a template (50 mm diameter, 10 mm thick). After the mortar had hardened, metal tie rods were glued to the clay mortar to be tested after 27 days with epoxy resin adhesive in order to carry out the adhesive tensile test.

The adhesive pull values were checked in each case according to the following storage conditions in accordance with DIN CEN 1897: Normal climate storage (NK): 28 days at 23 ° C and 50% atmospheric humidity. Heat storage (WL):

14 days normal climate storage and then 14 days storage at 70 ° C. The adhesive pull values were determined in accordance with DIN 18156 in each case after the abovementioned storage with a pull-off device from Herion with a load increase rate of 250 N / s. The measured values in N / mm ² represent mean values from 5 measurements. The adhesive tensile strengths were determined after 2 storage conditions:

Testing the water absorption: In accordance with DIN 52617, a 4 mm thick layer of clay mortar was leveled on aerated concrete slabs in accordance with DIN 52617. After the clay mortar had dried, the test specimens were sealed at the side edges and immersed in the water with the mortar layer down. The water absorption in kg / m ² h ⁰ ' ^{5 was then} determined from the weight increase per area and time unit (Table 1).

Weather resistance test: Various clay mortars were applied in a 10 mm thick layer to primed concrete slabs and exposed to the weather for 15 months after drying in the open air for 28 days. The influence of the weather on the clay mortar layer was assessed visually at monthly intervals. Table 1 shows when the mortal layer had fallen off.

Table 1:

* = Sample disintegrates after 30 minutes - no test possible ** = mortel layer was still completely intact after 15 months

Claims

Claims:

1. Use of water-redispersible, emulsifier-free polymer powder compositions containing one or more film-forming polymers, one or more protective colloids, and optionally antiblocking agents, in earth building materials.

2. Use according to claim 1, characterized in that a film-forming polymer is present, based on one or more monomers from the group comprising vinyl esters, (meth) acrylic acid esters, vinyl aromatics, olefins, 1,3-dienes and vinyl halides and optionally further monomers copolymerizable therewith.

3. Use according to claim 2, characterized in that a film-forming polymer is selected from the group consisting of vinyl acetate homopolymer, Mischpolymerisa ^¬ te with vinyl acetate and ethylene, copolymers with vinyl acetate, ethylene and a Vinylester of α-branched monocarboxylic acids having 9 to 11 carbon atoms, copolymers with n-butyl acrylate and 2-ethylhexyl acrylate and / or methyl methacrylate, copolymers with styrene and one or more monomers from the group consisting of methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, mixed polymer with vinyl acetate and one or more monomers from the group consisting of methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate and optionally ethylene, copolymers with 1,3-butadiene and styrene and / or methyl methacrylate and optionally further acrylic acid esters.

4. Use according to claim 1 to 3, characterized in that 0.1 to 30 wt .-% protective colloid is contained, from the group comprising partially saponified or fully saponified polyvinyl alcohols, polyvinyl pyrrolidones, polyvinyl acetals, starches, celluloses and their derivatives, proteins, lignin sulfonates, Poly (meth) acrylic acid, copolymers of (meth) - acrylates with carboxyl-functional comonomer units, poly (meth) acrylamide, polyvinylsulfonic acids and their water-soluble copolymers, melamine-formaldehyde sulfonates, naphthalene-formaldehyde sulfonates, styrene maleic acid and vinyl ether maleic acid copolymers.

5. Use according to claim 1 to 4, characterized in that 1 to 30 wt .-% antiblocking agent is included.

6. Use according to claim 1 to 5 in clay base plasters, clay decor plasters and clay decor paints.

7. Use according to claim 1 to 5 in clay mortars and in clay fillers.

8. Use according to claim 1 to 5 in clay building adhesives.

9. Use according to claim 1 to 5 in clay moldings.