Novel siloxane containing block copolymers, process for their preparation and their use for lubricants

Linear polyester-polysiloxane block copolymers of the general formula (I)

• [(—S—P—)p(—S-Q-)q(—S-T-)t]r (I)
• in which the (—S—P—), (—S-Q-) and (—S-T-) units are bonded to one another in any sequence and in which
• p=1 to 10,
• q=1 to 10,
• t=0 to 10,
• r=1 to 100,
• and r*p≧3 and r*q≧3, characterized in that S is a divalent siloxane unit of the general formula (II)
• where
• N=a+b+c+2=3 to 850,
• a=1 to 800,
• b=0 to 10,
• c=0 to 10,
• R1 are the same or different and are each independently selected from the following group:
• saturated or unsaturated, branched or unbranched alkyl radicals having 1 to 30 carbon atoms, alkaryl or arylalkyl radicals having 7 to 30 carbon atoms, aryl radicals having 6 to 30 carbon atoms,
• R3 are independently identical or different radicals of the general formula (IIa)
• where
• a, b, c and R1 are each as defined for formula (I) and
• R3═R1 or R3 as defined in formula (I),
• P is a divalent polyester unit of the general formula (III)
• where
• Rp2 is hydrogen or methyl,
• m is 0 to 21,
• Rp1 is a divalent organic radical of the general formula (IIIa)
• where
• n=1 to 100,
• o=1 to 100,
• p=0 to 17,
• Rp3 is a divalent branched or unbranched, saturated or unsaturated alkyl radical having 2 to 20 carbon atoms,
• Rp4 is hydrogen or methyl,
• Rp5 is a divalent branched or unbranched, saturated or unsaturated alkyl radical having 2 to 20 carbon atoms,
• Q is a divalent straight-chain or cyclic, uncharged or positively charged alkyl radical which is optionally interrupted by oxygen atoms and is interrupted at least by one optionally alkyl-substituted nitrogen atom or bears at least one amino group,
• T is a divalent polyether unit of the general formula (IV)
• —Rt[C═O]i[O(C2H4-dR4dO)e(CfH2fO)gMn][C═O]iRt— (IV)
• where
• Rt is a divalent linear, branched or cyclic alkyl radical having 2 to 23 carbon atoms,
• R4 is in each case independently hydrogen or a saturated or unsaturated alkyl radical or aryl radical which has 1 to 22 carbon atoms and may optionally contain oxygen or nitrogen atoms and
• d is in each case independently 0 to 2,
• e is 0 to 50,
• f is 2 to 4,
• g is 0 to 50, with the proviso that e+g>0,
• M is the same or different and is a divalent saturated or unsaturated, linear, branched or cyclic hydrocarbon radical which is optionally interrupted by oxygen or nitrogen atoms or carboxyl groups and is optionally substituted, at any position within T,
• h is 0, 1 or 2 and
• i is 0 or 1.