Novel shrinkage reducing admixture for inorganic binders

Abstract

The present invention relates to the use of polyoxyalkylenes of the carboxylic acid type as low-emission shrinkage reducers in inorganic binders, to a method for reducing the shrinkage and to the corresponding compositions.

Description

[0001] This application is a divisional application of the application "201680051596.5" filed on July 06, 2016, entitled "Novel Shrinkage Reducing Agent for Inorganic Binders". TECHNICAL FIELD

[0002] The present invention provides polyoxyalkylenes based on carboxylic acids as novel low-emission shrinkage-reducing agents for inorganic binders, in particular cementitious binders, and building materials, such as mortars, screeds, concretes and grouts, produced therefrom. BACKGROUND

[0003] It is well known to the skilled person that inorganic binders, in particular cementitious binders, undergo a volume shrinkage during the setting and drying process. This shrinkage is of great importance for the usability, the service life and the strength of the hardened building material, since it is often the cause of crack formation, hollowing of screeds and other defects. In this way, for example, water, dissolved salts and air enter the interior of the concrete, mortar, screed or grout through the cracks and accelerate the corrosion, for example, in reinforced concrete constructions. Furthermore, periodic stresses caused by freezing and thawing, with the undesired penetration of water into the building material, lead to mechanical stresses and premature material failure.

[0004] Therefore, the building industry is trying to limit the shrinkage to a minimum by various different measures. Attempts have been made to counteract the shrinkage not only by the way of execution of the construction and the selection of optimized cementitious binder compositions, but also, in recent times, by the addition of organic additives to enhance the degree of counteracting the shrinkage. In the early 1980s, the first shrinkage reducing agents (P. Betontechnische Berichte 2007-2009, pages 19-37). Since then, the use of various shrinkage reducing agents as admixtures has become widespread and has been the subject of scientific research relating to the mechanism of action (P. Thesis, University of Weimar, 2009).

[0005] The prior art includes the use of various types of diols and polyoxyalkylenes as said shrinkage reducing agents. For example, US 4,547,223 discloses the use of polyoxyalkylenes prepared starting from an alkyl alcohol having 1 to 7 carbon atoms or an OH-functional cycloaliphatic compound having 5 or 6 carbon atoms and containing 1 to 10 monomeric units of ethylene oxide and / or propylene oxide. GB 2305428 describes the shrinkage reducing action of various diols such as 2-methylpentane-2,4-diol and alkoxylated products prepared therefrom having 2 to 10 units of ethylene oxide and / or propylene oxide. In contrast, EP 1024120 relies on specific alkanolamines such as N-propylaminopropanol or N-butylaminopropanol. In JP 201 1246286 polyethylene glycols having a molar mass of 400 to 8000 g / mol are claimed as shrinkage reducing agents, while CN 100347 139 describes the use of polyoxyalkylenes derived from C 12 -C 18 Fatty alcohol ethoxylates formed from fatty alcohols. Polyoxyalkylenes derived from polyols having at least three OH groups and having 30 to 50 units of alkylene oxide per OH group are used in JP 2010229015 to reduce shrinkage in hydraulic binders. Several patents relate to the use of polyoxyalkylenes based on butanol, for example documents JP 2004091259 (1 to 20 units of ethylene oxide or propylene oxide) and CN 102020432 (exclusively related to units of propylene oxide).

[0006] In addition, it is known that diols and polyoxyalkylenes can be added to cementitious systems in pulverulent, usually supported form. The process described in JP 201 1 184236 is based on the application of polyoxyalkylenes having 1 to 100 units of alkylene oxide bonded to an alkyl alcohol having 1 to 8 carbon atoms to an inorganic pulverulent carrier material. For example, 80 g of active ingredient on 160 g of carrier material is converted into a solid-coated form by absorption.

[0007] All of these shrinkage reducing agents have one or more disadvantages. They are uneconomical due to their high dosage and / or production costs, they impair the action of air pore formers due to their surface activity, they cannot be used feasibly on construction sites due to their flammability / flash point, or they delay the stepwise development of the strength of the cementitious system.

[0008] A further problem not yet solved so far with the organic shrinkage reducing agents known so far is their vapour pressure. On large areas, such as during and after processing in mortars, for example, there is outgassing of volatile substances. Conventional shrinkage reducing agents are therefore volatile organic compounds (VOCs). When used in dwellings, they can cause contamination of the breathable air, which is tolerated to an ever decreasing extent in the case of carpets, furniture and plastics. In particular glycols and polyoxyalkylenes of low molecular weight, and also those which, due to their production method, have a broad molar mass distribution with low molecular weight components or contain low molecular weight by-products, can constitute a source of VOCs. In the long term, permanent gradual outgassing from building materials can impair the mechanical properties of the building materials.

[0009] Due to the potential health-damaging effects of volatile organic compounds in indoor air, floor coverings and floor covering adhesives have been tested for many years by defined test methods, and particularly low-emission materials are certified as quality seals. Materials which comply with the strict criteria of, for example, EMICODE EC1 and Blaue Engel are very particularly low-emission products. More and more attention is recently being focused on indoor-laid mortars, which, like their organic admixtures, are also possible sources of VOCs. So far, no organic shrinkage reducing agent for hydraulic binders is known which meets the requirements of, for example, EMICODE EC1 or similar test standards at conventional concentrations. SUMMARY

[0010] The problem addressed by the present application is therefore to provide a low-emission and almost VOC-free shrinkage reducing agent for hydraulic binders. A particular problem to be addressed is to provide a shrinkage reducing agent which meets the guidelines of the Ausschuss zur gesundheitlichen Bewertung von Bauprodukten (AgBB, German Commission for the Health-Related Evaluation of Building Products) (February 2015 version).

[0011] A further problem addressed by the present application is to provide a building material produced with a shrinkage reducing agent which meets the AgBB guidelines of TVOC3 < 10 mg / m 3 , TVOC 28 < 1.0 mg / m 3 and SVOC 28 < 0.1 mg / m 3 and is therefore also particularly suitable for very particular indoor use. (TVOC = total volatile organic compounds at day 3 or 28), SVOC = semi-volatile organic compounds at day 28.

[0012] The shrinkage reducing agents according to the present application will be available in liquid form (neat or diluted) or in solid form, for example in supported form, to enable maximum flexibility for the application. At the same time, the shrinkage reducing agents can also be used as components of product formulations together with other substances.

[0013] A further problem to be solved by the present application is to provide a new class of shrinkage reducing agents which are not only low-emission in the sense of the above definition, cheap to produce and easy to process, but also exhibit at least as good a shrinkage reduction as achieved by products known from the prior art.

[0014] When ranges, general formulae or classes of compounds are specified hereinafter, these are intended to encompass not only the respective ranges or classes of compounds explicitly mentioned, but also all subranges and sub-classes of compounds which can be obtained by leaving out individual values (ranges) or compounds. When documents are cited for the purposes of the present specification, the entire contents of these documents are intended to be part of the disclosure of the present application. When percentage figures are given hereinafter, these are values in % by weight, unless otherwise stated. In the case of compositions, percentage figures are based on the total composition, unless otherwise stated. When average values are given hereinafter, these are mass average values (weight average values), unless otherwise stated. When measurement values are given hereinafter, these are determined at a pressure of 101 325 Pa and a temperature of 25°C, unless otherwise stated.

[0015] It has surprisingly been found that specific polyoxyalkylenes having one or more carboxyl groups and one or more terminal hydroxyl groups in the polymer chain have excellent suitability as low-emission shrinkage reducing agents. This polyoxyalkylene, in liquid or solid form, if desired supported on an inorganic absorbent substrate, can be used in a versatile manner in, for example, mortars, cements and concretes or grouts, and shows an excellent shrinkage-reducing effect in such inorganic binder compositions. Investigations according to DIN 52450 have demonstrated that self-leveling cement mortars comprising the shrinkage reducing agents according to the present application have a very low shrinkage of less than 0.4 mm / m after 14 days.

[0016] In the context of the present application, low-emission and VOC-free shrinkage reducing agents are considered to be those which meet the guidelines of the German Commission for the Evaluation of Health Hazards of Building Products (AgBB), February 2015 version. These guidelines are known to the person skilled in the art. These have been published by the German Federal Ministry for the Environment on its web page:

[0017] http: / / www.umweltbundesamt.de / sites / default / files / medien / 355 / dokumente / agbb-bewertungsschema_2015_2.pdf .

[0018] The shrinkage reducing agents according to the present application are not volatile organic compounds (VOCs). They also do not contain any ingredients or by-products which would be classified as VOCs per se. Thus, the mortars and other building materials produced therewith are likewise almost free of unwanted VOCs and meet the AgBB criteria.

[0019] The term "VOC" is not defined univocally and the analytical determination methods also differ accordingly. A broad definition of VOCs is derived from the volatility (boiling point) of the substance or substance mixture. Thus, the term "VOC" describes substances having a boiling point of not more than 250°C. The fast VOC test by means of a GC-based test method has a particularly good applicability especially in the case of a large number of samples and allows a quick and meaningful characterization of the emission profile and a comparison between samples. The VOC measurement by means of the GC method against tetradecane as a standard substance proves that the shrinkage reducing agents according to the present application are not VOCs and the proportion of volatile components is extremely low. In contrast, conventional shrinkage reducing agents such as neopentyl glycol and hexanediol are 100% VOCs.

[0020] These results were confirmed in the method of the expensive and inconvenient 28-day test chamber, in which the emission properties of a mortar containing polyalkylene oxide according to the present application as an admixture were examined. According to the GEV (Gemeinschaft Emissionskontrollierte Verlegewerkstoffe, Klebstoffe und Bauprodukte e.V.) [German Association for Emission Control in Floor Coverings, Adhesives and Building Materials] test method (April 15, 2013 version), freshly prepared mortar samples in a large-volume test chamber which had been simulated under defined indoor climate conditions at 23°C were continuously flushed with clean air and the test chamber air was exchanged at specific intervals. Air samples were taken from the test chamber at intervals of several days, the volatile organic components were identified by GC-MS and HPLC and the addition was carried out. In such a test it was found that the adhesive compositions modified with the shrinkage reducing agents of the following formula (I) emit extremely low compared to the prior art admixtures examined.

[0021] A further advantage of the compounds according to the present application is that they are easy to process. With regard to the setting speed and the mechanical index of the cured adhesive systems, it was surprisingly found that the polyalkylene oxides according to the present application are neutral.

[0022] A further great advantage of the low-emission shrinkage reducing agents of the following formula (I) is also that, in the case of their use, cementitious mortars have the same properties as gypsum-based mortars, i.e. they emit low and do not have any shrinkage, while having better mechanical strength and higher water resistance.

[0023] Composition of a low-emission shrinkage-reducing agent according to the invention:

[0024] The present application therefore provides the use of polyalkylene oxides of the formula (I) as shrinkage reducers (equivalent to shrinkage-reducing agents):

[0025]

[0026] wherein

[0027] R is a valent, linear or branched, saturated, mono- or polyunsaturated aliphatic, cycloaliphatic or aromatic hydrocarbon radical having 3 to 38 carbon atoms, preferably having 5 to 17 carbon atoms, wherein the hydrocarbon radical is preferably substituted at the terminal position in the case of a linear hydrocarbon radical chain (i.e. at one or both ends of the linear hydrocarbon radical chain) by a polyalkylene oxide radical A, "substituted" in the present context meaning that one hydrogen atom of the hydrocarbon radical R is replaced in each case by a polyalkylene oxide radical A,

[0028] R is preferably a linear or branched, saturated, mono- or polyunsaturated aliphatic hydrocarbon radical having 3 to 38 carbon atoms, preferably having 5 to 17 carbon atoms, wherein the hydrocarbon radical chain is substituted at the terminal position by 1 or 2 (a = 1 or 2), preferably by 1 polyalkylene oxide radical A,

[0029] R is more preferably a linear, saturated or unsaturated aliphatic hydrocarbon radical having 5 to 17 carbon atoms, wherein the hydrocarbon radical chain is substituted at the terminal position by a polyalkylene oxide radical A (a = 1),

[0030] a = 1 to 4, preferably less than 3, further preferably 1 to 2, particularly preferably 1,

[0031] n = 0 to 40, preferably 2 to 30, particularly preferably 4 to 20,

[0032] m = 0 to 40, preferably 2 to 30, particularly preferably 4 to 20,

[0033] with the proviso that

[0034] the sum of n and m = 4 to 80, preferably 6 to 40, more preferably 8 to 20, wherein the units referred to by n and m are distributed in block form or randomly in the polyether chain, and the units referred to by n and m constitute the average value of the possible statistical distribution of the structures actually present.

[0035] The polyalkylene oxide radical A corresponds to the fragment having the index a in formula (I).

[0036] The shrinkage reducers of the formula (I) are particularly distinguished by low emissions and by meeting the AgBB criteria mentioned above.

[0037] In the context of the present invention, shrinkage reducing admixtures are organic compounds that reduce the shrinkage of hydraulic binders. The shrinkage occurs during the drying operation by capillary suction, which is due to internal chemical shrinkage or in the case of very low external air humidity. The use of shrinkage reducing admixtures reduces the stresses and prevents or limits cracking. The function and mode of action have been described in detail several times in the literature (Eberhardt 2011 ; "On the mechanisms of shrinkage reducing admixtures in self consolidating mortars and concretes", ISBN 978-3-8440-0027-6).

[0038] The statistical distribution can have block structures with any number of blocks and in any order or obey a randomized distribution; they can also have alternating structures or form a gradient along the chain; in particular, they can also form any mixture thereof, in which groups of different distributions can follow one another.

[0039] Preferably, polyoxyalkylenes of the formula (I) are used, in which the R groups are independently aliphatic hydrocarbon radicals having 3 to 38 carbon atoms, preferably having 5 to 17 carbon atoms, wherein the carbon chain ends are substituted by 1 or 2 polyoxyalkylene groups A, a is thus the number of polyoxyalkylene groups A and is 1 or 2, the R groups are more preferably branched by 5 to 17 carbon atoms and the index a is 1.

[0040] The polyoxyalkylenes of the formula (I) can be prepared by the alkoxylation of carboxylic acids of the formula (II) with alkylene oxides such as ethylene oxide and / or propylene oxide:

[0041]

[0042] in which

[0043] R is an a-valent radical of an organic carboxylic acid as defined in formula (I).

[0044] Preferred R groups of formula (I) and formula (II) are those derived from compounds from the group of mono- or poly-carboxylic acids, aromatic carboxylic acids or cycloaliphatic carboxylic acids. Particularly preferred are R groups derived from fatty acids or dimer fatty acids. Especially preferred are R groups derived from hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic acid, icosanoic acid, 2-ethylhexane carboxylic acid, isononanoic acid, 3,5,5-trimethylhexane carboxylic acid, neodecanoic acid, isotridecanoic acid, isostearic acid, undecylenoic acid, oleic acid, linoleic acid, ricinoleic acid, linolenic acid, benzoic acid, cinnamic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexane carboxylic acid, hexahydrophthalic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid or dimer fatty acids derived from the above mentioned unsaturated carboxylic acids. From the above mentioned groups, further particularly preferred are R groups derived from hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic acid, icosanoic acid, 2-ethylhexane carboxylic acid, isononanoic acid, 3,5,5-trimethylhexane carboxylic acid, neodecanoic acid, isotridecanoic acid, isostearic acid, undecylenoic acid, oleic acid, linoleic acid, ricinoleic acid, linolenic acid or dimer fatty acids derived from the above mentioned unsaturated carboxylic acids, very particularly preferred are hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic acid, icosanoic acid, 2-ethylhexane carboxylic acid, isononanoic acid, 3,5,5-trimethylhexane carboxylic acid, neodecanoic acid, isotridecanoic acid, isostearic acid, undecylenoic acid, oleic acid, linoleic acid, ricinoleic acid or linolenic acid, and especially preferred are isononanoic acid, 3,5,5-trimethylhexane carboxylic acid, neodecanoic acid, isotridecanoic acid, oleic acid.

[0045] Polyoxyalkylenes of formula (I) wherein the R groups are derived from the above mentioned carboxylic acids have a particularly excellent suitability as shrinkage reducing agents, have particularly good properties in terms of processability and achieve building materials having desired properties when used as shrinkage reducing agents.

[0046] In addition, also aromatic carboxylic acids of formula (II) can be used, for example benzoic acid, cinnamic acid, phthalic acid, isophthalic acid, terephthalic acid or cycloaliphatic carboxylic acids such as cyclohexane carboxylic acid, hexahydrophthalic acid, tetrahydrophthalic acid or methyltetrahydrophthalic acid.

[0047] The target polyoxyalkylenes here are polyether alcohols, which are often also simply referred to as polyethers or polyether alcohols. The prior art includes various documents in which alcohols, carboxylic acids or amines are used as starter compounds for the alkoxylation reaction. "N. Surface Active Ethylene Oxide Additives, Pergamon Press, 1969" gives a good overview of polyoxyalkylenes and methods for preparing polyoxyalkylenes.

[0048] The polyoxyalkylenes according to the application preferably have a weight average molar mass of 300 to 15 000 g / mol, more preferably 400 to 5000 g / mol and especially preferably 500 to 2500 g / mol.

[0049] Particularly preferred are the polyoxyalkylenes according to the application, wherein n = 0 to 20, m = 0 to 20 and the sum of m + n = 6 to 20.

[0050] Especially preferred are the polyoxyalkylenes according to the application, wherein R is a monovalent (a = 1) branched hydrocarbon radical having 5 to 17 carbon atoms and wherein n = 0 to 20, m = 0 to 20 and the sum of m + n = 6 to 20.

[0051] The compounds according to the application used as reducing agents preferably also include polyoxyalkylenes which originate from mixtures of various carboxylic acids, for example mixtures of different natural fatty acids and mixtures of monomer / dimer / trimer fatty acids. If a plurality of starter compounds of the mixture is used, the index a can also be subject to a statistical distribution.

[0052] The polyoxyalkylenes according to the application are preferably colourless to yellow / orange products which can be transparent or opaque. Depending on the structure of the polyoxyalkylene chain, the products are liquid, waxy or solid at room temperature. Liquid and low-viscosity products with less than 1000 mPas (25°C) are preferred.

[0053] The low-emission reducing agents of the application of the formula (I) can be prepared by methods known from the prior art; they are preferably prepared by the following method. In a first step, the starter compound of the formula (II) is catalytically reacted with ethylene oxide, propylene oxide or any desired mixture of these epoxides. In an optional second step, residual monomers are removed in a vacuum distillation, the reaction product is neutralised with an acid, such as lactic acid, acetic acid, propionic acid or phosphoric acid, and the formed salts are optionally removed by filtration.

[0054] In the context of the present application, starter compound is understood to mean the initial (starting) substance which forms the polyoxyalkylene to be prepared by addition of the oxyalkylene.

[0055] The epoxide monomers can be used in pure form or in mixed form. Further epoxide can also be continuously dosed over time to the epoxide already present in the reaction mixture to cause an increasing concentration gradient of the continuously added epoxide. The polyoxyalkylenes formed are thus subject to a random distribution in the final product. The correlation between the dosing and the product structure is known to the person skilled in the art.

[0056] The catalysts used for the alkoxylation reaction are basic catalysts known to the person skilled in the art, such as potassium hydroxide, potassium hydroxide solution, sodium methoxide or potassium methoxide. The starting compound and the catalyst are initially fed to the reactor at the beginning of the process before the dosing of the alkylene oxide, the amount of catalyst needs to be adjusted to obtain sufficient catalytic activity for the process. The reaction temperature in the first step is preferably from 80 to 220 °C, more preferably from 100 to 180 °C. The pressure in the first step is preferably from 0.5 bar to 20 bar, preferably from 1.0 bar to 12 bar (absolute pressure).

[0057] After the addition of the epoxide has ended, further reaction to complete the conversion is preferably carried out for a period of time subsequently. The further reaction can be carried out, for example, by continuous reaction under the reaction conditions, i.e. for example, the reaction temperature and pressure are maintained, without the addition of reactants. Preferably, the further reaction is carried out with mixing of the reaction mixture, in particular under stirring.

[0058] The unreacted epoxide and any other volatile components can be removed directly at the end of the first step, for example by vacuum distillation, steam or gas stripping or other deodorization methods.

[0059] The reactor used for the alkoxylation in the first process step can in principle be any suitable reactor type which allows control of the reaction and its exothermicity. The first process step can be carried out continuously, semi-continuously or batchwise in a manner known in chemical engineering.

[0060] Application of a low-emission shrinkage-reducing agent:

[0061] The present application further provides a method for reducing the shrinkage of a construction material comprising an inorganic binder, in particular a cementitious binder. The construction material is preferably a mortar, a screed, a concrete or a grout. In the context of the method at least one polyalkylene oxide of formula (I) as described above is added to the unhardened or unconsolidated construction material mixture. The inorganic binder is preferably a hydraulic binder, more preferably a cement according to European Standard EN 197, in pure form or in a blend with latent hydraulic binders, preferably fly ash, blast furnace slag, fuel oil shale, natural pozzolans or calcined silica or inert fillers such as stone dust. It is further preferred in the context of the method that the at least one polyalkylene oxide of formula (I) is added to the unhardened construction material mixture in an amount of 0.001 to 6.0 wt.-%, preferably in an amount of 1 to 3 wt.-%, based on the dry weight of the inorganic binder. In this context the term "unhardened construction material mixture" is to be interpreted such that the mixture does not necessarily contain all components of the later construction material at the time of addition; in other words, further ingredients required for the desired construction material, such as water or aggregates, can be added, for example, after the addition of the at least one polyalkylene oxide of formula (I). The term "unhardened" is to be interpreted such that the inorganic binder is in unconsolidated or at least not fully consolidated form, such that the mixture is free-flowing and preferably pumpable.

[0062] The polyalkylene oxide of formula (I) can be used in liquid form as a powder, for example in a supported, dispersed or emulsified form in water and / or non-aqueous solvents, or dissolved in water and / or non-aqueous solvents. The polyalkylene oxide of formula (I) can be pre-mixed in the at least one hydraulic binder, or it can be used in dry mortar or concrete. The incorporation of the polyalkylene oxide of formula (I) into the binder can take place before, during or after the grinding of the binder in the factory.

[0063] In the context of the supported operation, one or more polyalkylene oxides of formula (I) of the present application are absorbed, encapsulated or adsorbed on a carrier or mixed with a carrier material, wherein the carrier material can be selected from inorganic or organic materials or mixtures thereof, preferably silicon dioxide, aluminium oxide, sand, cement, volcanic rock (e.g. basalt or pumice), fly ash, bentonite, xonotlite or lime or starch, cellulose, wood pellets or proteins, plastic pellets, with the use of inorganic carrier materials being particularly preferred for cost reasons. More particularly preferred carrier materials are silicon dioxide, aluminium oxide and pumice, with silicon dioxide being especially preferred.

[0064] It can be appropriate when at first at least one polyalkylene oxide of the formula (I), inorganic binder, admixture, additive and / or aggregate are mixed without the addition of water and only at a later point in time water is added to the premix thus obtained. Alternatively, however, the individual components, i.e. at least one polyalkylene oxide of the formula (I), inorganic binder, admixture, additive and / or aggregate, can also be mixed directly with water. In addition, at least one polyalkylene oxide of the formula (I) can be mixed with the inorganic binder and / or stone dust during the production or transport process of the construction material. To this end, at least one polyalkylene oxide of the formula (I) can be added directly to the mixture, for example to the binder, mortar or concrete, the latter in dry form or already mixed with water in the factory, on the construction site, in a mixer, in a transport pump or by means of a static mixer with a powder metering unit or a liquid metering unit.

[0065] In the context of the present application, "construction material" means a mixture consisting of one or more inorganic binders and water, preferably a mixture consisting of one or more inorganic binders, aggregate and water. The construction material is more preferably concrete, mortar, sand mortar or grout. The expression "inorganic binder" is to be understood in particular as meaning a binder which, in the presence of water, reacts in a hydration reaction to give a solid hydrate or hydrate phase. This can include, for example, a hydraulic binder (for example cement or hydraulic lime), a latent hydraulic binder (for example castable sand), a pozzolanic binder (for example fly ash), a non-hydraulic binder (for example gypsum, slaked lime) or a mixture of two or more of these binders. "Cement" or "cementitious binder" is to be understood primarily as meaning a binder or binder composition having a proportion of cement clinker of at least 5% by weight, in particular at least 20% by weight, preferably at least 35% by weight, in particular at least 65% by weight. The cement clinker is preferably Portland cement clinker. The present application is suitable for cements, for example according to the standard EN 197-1, in particular for CEM I, CEM II, CEM III, CEM IV and / or CEM V type cements. Of course, it is also suitable for cement types which are classified according to another standard or which are not classified (for example high-alumina cement, calcium sulfoaluminate cement, belite cement, geopolymer and blends thereof).

[0066] In addition to at least one polyoxyethylene according to formula (I) of the present invention, the building materials or mixtures thereof may also contain conventional admixtures. Examples include concrete plasticizers, superplasticizers, corrosion inhibitors, defoamers, porosiform agents, polymer dispersions, accelerators, retarders, stabilizers, viscosity modifiers, redispersible powders, water-retaining agents, fibers (e.g., steel fibers or polymer fibers), and sealants. Furthermore, the building materials or mixtures thereof may contain conventional admixtures such as fly ash, foundry sand, stone powder (e.g., quartz powder / limestone powder), fibers (e.g., steel fibers or polymer fibers), pigments, pumice volcanic ash, and polymer dispersions. Additionally, the building materials or mixtures thereof may contain aggregates such as sand, gravel, crushed stone, and / or stone. Here, it is not important whether the inorganic binders, admixtures, additives, aggregates, etc., are premixed in the form of a "dry mixture" and the latter is then blended with water at a later time point, or whether individual components are mixed with water.

[0067] Another aspect of the present invention relates to a building material composition comprising:

[0068] i) at least one inorganic binder, preferably a cementitious binder, and

[0069] ii) At least one polyoxyethylene of formula (I) as described above. For preferred embodiments regarding the configuration of at least one polyoxyethylene of formula (I), its content in the composition, and other components of the building material composition, reference can be made to the above details, including details regarding building materials and mixtures of building materials, which are similarly applicable to the building material compositions according to the invention.

[0070] The embodiments described below are examples of the invention and are not intended to limit the invention to the embodiments described in detail. The scope of protection of this invention can be readily obtained from the entire specification and claims.

[0071] The following description, by way of example, describes the low-emission polyoxyethylene according to the invention, its preparation method, and its use as a shrinkage reducer according to the invention. There is no intention to limit the invention to these illustrative embodiments. Detailed Implementation

[0072] Example:

[0073] GPC Measurement:

[0074] GPC measurements used to determine molecular weight distribution and average molar mass Mw were performed under the following measurement conditions: SDV1000 / Column combination (length 65 cm), temperature 30°C, mobile phase THF, flow rate 1 ml / min, sample concentration 10 g / l, RI detector, evaluation against a relative polypropylene glycol standard.

[0075] Determination of the OH number:

[0076] The hydroxyl number is determined according to the method DGF CV 17a (53) of the Deutsche Gesellschaft für Fettwissenschaft. This involves acetylation of the sample with acetic anhydride in the presence of pyridine and determination of the consumption of acetic anhydride by titration with 0.5 n potassium hydroxide solution in ethanol using phenothalin.

[0077] Determination of the viscosity:

[0078] The viscosity is measured at 25°C with a Haake RV 12 rotational viscometer according to DIN 53019.

[0079] Determination of the VOC content:

[0080] a) Chamber test

[0081] The chamber test is carried out according to the test method "Bestimmung flüchtiger organischer Verbindungen zur Charakterisierung emissionskontrollierter Verlegewerkstoffe, Klebstoffe, Bauprodukte und Parkettlacke" [Determination of volatile organic compounds for the characterization of emissions-controlled flooring materials, adhesives, building products and parquet lacquers] from the German Emissions Control Association for Floor Coverings (GEV), version 15.04.2013. The mortar samples containing the respective shrinkage reducing agent are prepared with water, introduced into a metal pan and placed in a test chamber at 301. Storage takes place at 23°C, 50% relative humidity and 0.5 air exchange per hour. After 3 days, 10 days and 28 days, two samples each are taken from the gas space of the test chamber: one sample is used for analysis of the emissions by GC-MS (Tenax), the other sample is used for determination of the aldehydes by means of HPLC (DNPH).

[0082] b) Rapid method by means of GC

[0083] The VOC measurement was carried out by gas chromatography according to DIN EN ISO 11890-2 "Paints and varnishes - Determination of volatile organic compound (VOC) content" using tetradecane with a boiling point of 251 °C at standard conditions as marker. VOCs are considered to be all compounds with a residence time lower than that of the marker. The content of VOCs is determined by peak area calculation and represents the percentage mass proportion of volatile organic ingredients based on the total amount of the sample analyzed.

[0084] Mixing of the construction material (construction material mixture):

[0085] The production of the mixture was carried out according to DIN EN 206-1. Cement and any admixtures, additives and aggregates were premixed in a mixer, such as a pan mixer. After completion of the addition of water and after the subsequent addition of superplasticizer or concrete plasticizer, the mixture was mixed again in each case.

[0086] Determination of the consistency of the fresh construction material mixture:

[0087] The slump flow was determined according to DIN EN 12350-5 or according to DIN EN 13395-1.

[0088] The determination of the slump was carried out according to DIN EN 12350-8. The "slump cone" was used instead of the "slump flow cone". The other methods used are described in the DAfStb [German Committee for Structural Concrete] guideline "Herstellung und Verwendung von zementgebundenem Vergussbeton und " [Production and use of cement-bound cast concrete and cast mortar].

[0089] Determination of the air content of the fresh construction material mixture:

[0090] The air content was determined according to DIN EN 12350-7. The volume of the air content test instrument was 1 liter or 5 liters.

[0091] Determination of the early shrinkage:

[0092] ​Shrinkage and swelling operations of building material samples during the setting process are measured with the aid of a shrinkage channel. Fresh mortar is introduced into a metal channel made of stainless steel. A ram, which is movably mounted on one side of the channel, transmits the length change to a highly sensitive transducer. On the other end of the channel is a barbed hook which holds the sample against the channel wall. The same hook is present on the transducer ram. The sample is held in the channel in an almost frictionless manner.

[0093] Determination of the long-term shrinkage of solid building material mixtures:

[0094] Shrinkage is carried out according to DIN 52450 (1985). The alternative method is based on this standard. The difference is the use of test specimens with dimensions of 100 mm x 100 mm x 500 mm and the corresponding test apparatus.

[0095] Determination of the compression and flexural tensile strength of solid building material mixtures:

[0096] The compression and flexural tensile strength is tested according to DIN EN 12390-3, DIN EN 12390-5, DIN EN 196-1 and DIN EN 13892-2.

[0097] Synthesis examples for shrinkage-reducing agents:

[0098] Example 1:

[0099] Preparation of polyalkylene oxide from 3,5,5-trimethylhexanoic acid and 8 mol PO

[0100] The initial charge of 806 g 3,5,5-trimethylhexanoic acid and 18.5 g KOH in a 5 liter autoclave was heated to 130°C while stirring. The reactor was evacuated to an internal pressure of 30 mbar in order to remove any volatile components present by distillation and to inertize with nitrogen. 2367 g of propylene oxide were metered in over 4 h at an internal temperature of 130°C and an internal pressure of 3 to 4 bar (absolute pressure). After a further reaction time of 1.5 h at 130°C, the volatile components were removed by distillation at 130°C at reduced pressure. The alkoxylate product was cooled to below 90°C, neutralized with phosphoric acid and discharged from the reactor through a filter. The product was almost colorless and had a low viscosity at room temperature. The OH number was 101 mg KOH / g and the acid number was 0.1 mg KOH / g. According to GPC analysis, the weight average molar mass Mwof the product was 680 g / mol, the molecular weight distribution Mw / Mnwas 1.11. w w n

[0101] Example 2: ​​​

[0102] Preparation of polyoxyalkylenes from 3,5,5-trimethylhexanoic acid and 12 mol EO

[0103] The initial charge of 806 g 3,5,5-trimethylhexanoic acid and 12.5 g KOH in a 5 liter autoclave was heated to 130°C while stirring. The reactor was evacuated to an internal pressure of 30 mbar to remove any volatile components present by distillation and inertized with nitrogen. 2689 g of ethylene oxide were metered in over 2 h 40 min at an internal temperature of 160°C and a maximum internal pressure of 4.5 bar (abs). After a further reaction time of 1 h at 160°C, the volatile components were removed by distillation at reduced pressure at 160°C. The alkoxylated product was cooled below 90°C, neutralized with phosphoric acid and discharged from the reactor through a filter. The product was almost colorless and had a low viscosity at room temperature. The OH number was 88.5 mg KOH / g and the acid number was 0.3 mg KOH / g. According to GPC analysis, the product had a weight average molar mass Mwof 680 g / mol and a molecular weight distribution Mw / Mnof 1.12. w and 1.12. w / M n .

[0104] Example 3:

[0105] Preparation of polyoxyalkylenes from neodecanoic acid and 8 mol EO

[0106] The initial charge of 689 g neodecanoic acid and 3.6 g potassium hydroxide solution (45%) in a 5 liter autoclave was heated to 130°C while stirring. The reactor was evacuated to an internal pressure of 30 mbar to remove any volatile components present by distillation and inertized with nitrogen. 1408 g of ethylene oxide were metered in over 3.5 h at an internal temperature of 170°C and a maximum internal pressure of 4.5 bar (abs). After a further reaction time of 0.5 h at 170°C, the volatile components were removed by distillation at reduced pressure. The alkoxylated product was cooled below 90°C, neutralized with lactic acid and discharged from the reactor through a filter. The product was almost colorless and had a low viscosity at room temperature. The OH number was 101.9 mg KOH / g and the acid number was 0.1 mg KOH / g. According to GPC analysis, the product had a weight average molar mass Mwof 540 g / mol and a molecular weight distribution Mw / Mnof 1.09. w and 1.09. w / M n .

[0107] Example 4:

[0108] Preparation of polyoxyalkylenes from 3,5,5-trimethylhexanoic acid, 8 mol PO and 8 mol EO

[0109] Preparation according to Example 1, except that initially 403 g 3,5,5-trimethylhexanoic acid and 5.8 g potassium methoxide were charged to the autoclave and at 130 °C a homogeneous mixture of 1182 g propylene oxide and 897 g ethylene oxide was metered in. The alkoxylated product, neutralized with phosphoric acid, was almost colorless and had a low viscosity at room temperature. The OH number was 58.2 mg KOH / g and the acid number was 0.2 mg KOH / g. According to GPC analysis, the product had a weight average molar mass Mwof 935 g / mol and a molecular weight distribution Mw / Mnof 1.12. w and 1.12. w / M n .

[0110] Example 5:

[0111] Preparation of polyoxyalkylenes from benzoic acid and 5 mol EO and 5 mol PO

[0112] Preparation according to Example 1, except that initially 488 g benzoic acid and 7.5 g sodium methoxide were charged to the autoclave and at 130 °C first 880 g ethylene oxide and then 1160 g propylene oxide were metered in. The alkoxylated product of the block structure, neutralized with phosphoric acid, was yellowish and had a low viscosity at room temperature. The OH number was 90.1 mg KOH / g and the acid number was 0.1 mg KOH / g. According to GPC analysis, the product had a weight average molar mass Mwof 610 g / mol and a molecular weight distribution Mw / Mnof 1.14. w and 1.14. w / M n .

[0113] Example 6:

[0114] Preparation of polyoxyalkylenes from oleic acid and 12 mol EO

[0115] Preparation according to Example 3, except that initially 561 g oleic acid and 2.5 g potassium hydroxide solution (45%) were charged to the autoclave and at 150 °C 1056 g ethylene oxide was metered in. The alkoxylated product, not neutralized, was brown and had a low viscosity at room temperature. The OH number was 71.3 mg KOH / g and the acid number was 0.0 mg KOH / g. According to GPC analysis, the product had a weight average molar mass Mwof 785 g / mol and a molecular weight distribution Mw / Mnof 1.16. w and 1.16. w / M n .

[0116] Example 7:

[0117] Preparation of the powder in supported form

[0118] Initially, a stirrer bowl of a high-speed mixer (e.g. from Eirisch) was charged with 333 g of silica and 67 g of polyoxyalkylene according to example 1 (3,5,5-trimethylhexanoic acid + 8 PO). Thereafter, mixing was carried out for 5 minutes at 2000 rpm.

[0119] Analysis of the VOC content

[0120] The VOC content of the pure polyoxyalkylenes was analyzed by gas chromatography by means of the described quick test.

[0121] Table 1 : VOC content of shrinkage reducing agents

[0122]

[0123] For the selected samples, mortar samples modified with various shrinkage reducing agents were tested in a test chamber test (as described above) by means of the GEV method. The dosage was 0.3% active ingredient based on the entire mortar.

[0124] For the evaluation of the VOC emissions, the so-called TVOC (total volatile organic content; retention range C6-C16) was quoted and reported in toluene equivalents.

[0125] Table 2: TVOC values of mortar samples using shrinkage reducing agents in a test chamber test by means of the GEV method

[0126]

[0127] * For product group 1 : mineral products.

[0128] The conventional shrinkage reducing agents do not meet any of the GEV criteria of the current state of the art representing low-emission building materials. In contrast, the mortar utilizing the shrinkage reducing agent of the present application (example 1) achieves levels several times lower than the GEV criteria. The other compounds of the present application according to examples 2 to 7 achieve comparable TVOC values.

[0129] The detection of the shrinkage-reducing properties of the substances according to the present application was carried out on building material mixture preparations, which consist, inter alia, of 330 kg / m 3 cement, 1700 kg / m 3 sand and aggregates and 210 kg of water. The differences between the comparison mixtures only lie in the shrinkage-reducing component.

[0130] Table 3: Index of fresh and firm building material mixtures:

[0131]

[0132] ​Table 4: Early shrinkage values: The data given are normalized to the reference mixture. By definition, the value of the reference mixture at each measurement point is 100%. Values less than 100% mean that the shrinkage of the mixture is less than that of the reference mixture.

[0133]

[0134] Table 5: Long-term shrinkage values according to Graf-Kaufmann

[0135]

[0136] The shrinkage-reducing properties of the compounds according to the application were tested in a further building material formulation (Table 6) consisting of 647 kg / m 3 cement, 260 kg / m 3 ground limestone, 1293 kg / m 3 sand with a particle size of 0-2 mm and 453 kg / m 3 water. The reference used was a mixture without shrinkage reducer and with neopentyl glycol. The shrinkage was determined on test specimens with dimensions of 400 mm x 400 mm x 1600 mm according to DIN 52450 (1985).

[0137] Table 6: Long-term shrinkage values according to DIN 52450 (1985)

[0138]

Claims

1. A construction material composition with reduced shrinkage, comprising i) at least one inorganic binder, and ii) at least one polyalkylene oxide shrinkage reducing agent of formula (I): wherein R is independently a-valent, linear or branched, saturated aliphatic, cycloaliphatic or aromatic hydrocarbon group having 3 to 38 carbon atoms, wherein the hydrocarbon group is substituted by polyalkylene oxide groups A, a = 1 to 4, n = 0 to 40, m = 0 to 40, with the proviso that the sum of n and m = 4 to 16, wherein the units referred to by n and m are distributed in blocks or randomly in the polyether chain, and the units referred to by n and m constitute the average of the possible statistical distribution of the actually existing structure.

2. The building material composition according to claim 1, characterized in that The inorganic binder is a cementitious binder.

2. The construction material composition according to claim 1, wherein the polyalkylene oxide shrinkage reducing agent of formula (I) is present in an amount of 0.01 to 5 wt.-%, based on the total weight of the construction material composition.

3. The construction material composition according to claim 1 or 2, wherein the polyalkylene oxide shrinkage reducing agent of formula (I) is present in an amount of 0.1 to 1 wt.-%, based on the total weight of the construction material composition.

4. The construction material composition according to any one of claims 1 to 3, wherein the polyalkylene oxide shrinkage reducing agent of formula (I) is present in an amount of 0.2 to 0.5 wt.-%, based on the total weight of the construction material composition.

5. The construction material composition according to any one of claims 1 to 4, wherein the polyalkylene oxide shrinkage reducing agent of formula (I) is present in an

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