Defoamer compositions for building-product mixtures

A method of defoaming a building-product mixture comprising a binder and a superplasticizer comprising adding at least one siloxane of the formula (I)

• Ma1MAa2MBa3MCa4Db1DAb2DBb3DCb4Tc1TAc2TBc3TCc4Qd1 (Formula I)
• where
• a1=0 to 32,
• a2=0 to 10,
• a3=0 to 32,
• a4=0 to 10,
• b1=1 to 600,
• b2=0 to 10,
• b3=0 to 80,
• b4=0 to 20,
• c1=0 to 30,
• c2=0 to 10,
• c3=0 to 10,
• c4=0 to 10,
• d1=0 to 15,
• with the proviso that
• a1+a2+a3+a4>3, and;
• a3+b3+c3≧1, and;
• c1+c2+c3+c4>1,
• M=[R13SiO1/2]
• MA=[R2R12SiO1/2]
• MB=[R3R12SiO1/2]
• MC=[R4R12SiO1/2]
• D=[R12SiO2/2]
• DA=[R21R11SiO2/2]
• DB=[R31R11SiO2/2]
• DC=[R41R11SiO2/2]
• T=[R1SiO3/2]
• TA=[R2SiO3/2]
• TB=[R3SiO3/2]
• TC=[R4SiO3/2]
• Q=[SiO4/2],
• R1 independently represents at least one radical from the group of linear, cyclic or branched, aliphatic or aromatic, saturated or unsaturated hydrocarbon radicals having 1 up to 20 carbon atoms,
• R2 independently represents a hydrogen, alkoxy, carboxy, hydroxyl or sulphonic ester radical,
• R3 independently represents alike or unalike radicals from the group comprising
• —CH2—CH2—CH2—O—(CH2—CH2O—)x—(CH2—C(R′)2O—)y—(SO)z—R″
• —CH2—CH2—O—(CH2—CH2O—)x—(CH2—C(R′)2O—)y—R″
• where
• x=0 to 100,
• y=0 to 100,
• z=0 to 100,
• with the proviso that x may be alike or unalike y,
• R′ in each occurrence is the same or different and independently represents hydrogen and/or a saturated, unsaturated or aromatic hydrocarbon radical having 1 to 12 carbon atoms, optionally substituted with heteroatoms, with alkyl or aryl radicals, with haloalkyl, haloaryl radicals, wherein the heteroatoms are selected from the group consisting of O, N and/or S,
• R″ represents a hydrogen radical or an alkyl group of 1 to 4 carbon atoms, a group —C(O)—R′″ where R′″=alkyl radical, a group —CH2—O—R′, an alkylaryl group, e.g. a benzyl group, the group —C(O)NH—R′ or —C(O)0—R′,
• SO represents a styrene oxide radical —CH(C6H5)—CH2—O—,
• R4 independently represents alike or unalike radicals from the group of heteroatom-substituted linear, branched or cyclic, saturated, unsaturated or aromatic, optionally heteroatom-interrupted hydrocarbon radicals,
• and at least one superplasticizer based on polycarboxylate ethers or sulphonates of lignin, melamine or naphthalene or of resins thereof,
• wherein said at least one siloxane comprises at least two different polyalkoxylene moieties,
• wherein a 6.25 wt. % of said at least one siloxane of the formula (I) in water is clear at room temperature.