Method for producing polyurethane foam

1. A method for producing polyurethane foams comprising reacting at least one organic isocyanate containing two or more isocyanate functions, at least one polyol containing two or more isocyanate-reactive groups, and a blowing agent consisting of at least one halogenated olefin and at least one siloxane of formula (I):

a in each occurrence independently is from 1 to 300,

b in each occurrence independently is from 1 to 50,

c in each occurrence independently is >0 to 4,

d in each occurrence independently is >0 to 4,

with the proviso that, per molecule of formula (I), the average number Σd of T-units and the average number Σc of Q-units per molecule are neither greater than 20, the average number Σa of D-units per molecule is not greater than 1500 and the average number Σb of R 1 -bearing siloxy units per molecule is not greater than 50,

R in each occurrence independently is one or more than one moiety selected from the group consisting of linear, cyclic or branched, aliphatic or aromatic, saturated or unsaturated hydrocarbon moieties having 1 up to 20 carbon atoms,

R 2 in each occurrence independently is R 1 or R,

R 1 is unlike R and in each occurrence independently is an organic moiety and/or a moiety selected from the group consisting of:

—CH 2 —CH 2 —CH 2 —O—(CH 2 —CH 2 O—) x —(CH 2 —CH(R)O—) y —R″

—CH 2 —O—(CH 2 —CH 2 O—) x —(CH 2 —CH(R 1 )O—) y —R″

—CH 2 —R IV

—CH 2 —CH 2 —CH 2 —O—CH 2 —CH(OH)—CH 2 OH

—CH 2 —CH 2 —CH 2 —O—CH 2 —C(CH 2 OH) 2 —CH 2 —CH 3 , where

x is from 0 to 100,

x′ is 0 or 1,

y is from 0 to 100,

R′ in each occurrence independently is an alkyl or aryl group of 1 to 12 carbon atoms, and

R″ in each occurrence independently is hydrogen or an alkyl group of 1 to 4 carbon atoms, a —C(O)—R′″ group where R′″=alkyl, a —CH 2 —O—R′ group, an alkylaryl group, or a

—C(O)NH—R′ group,

R IV is a linear, cyclic or branched hydrocarbon moiety having 1 to 50 carbon atoms,

R 4 in each occurrence independently is R, R 1 and/or a heteroatom-substituted, functionalized, organic, saturated or unsaturated moiety selected from the group consisting of alkyl, aryl, chloroalkyl, chloroaryl, fluoroalkyl, cyanoalkyl, acryloyloxyaryl, acryloyloxyalkyl, methacryloyloxyalkyl, methacryloyloxypropyl and vinyl,

with the proviso that at least one substituent from R 1 , R 2 and/or R 4 is other than R.

2. The method according to claim 1 wherein

R 1 in each occurrence independently is an organic moiety

—CH 2 —CH 2 —CH 2 —O—(CH 2 —CH 2 O—) x —(CH 2 —CH(R′)O—) y —R″,

—CH 2 —CH 2 —O—(CH 2 —CH 2 O—) x —(CH 2 —CH(R′)O—) y —R″, or

—CH 2 —R IV

where

x is from 0 to 100,

y is from 0 to 100,

R′ in each occurrence independently is different and is methyl, ethyl and/or phenyl and,

R″ in each occurrence independently is hydrogen or an alkyl group of 1 to 4 carbon atoms, a —C(O)—R′″ group where R′″=alkyl, a —CH 2 —O—R′ group, an alkylaryl group, or a

—C(O)NH—R′ group,

R IV is a linear, cyclic or branched hydrocarbon moiety having 1 to 50 carbon atoms.

3. The method according to claim 1 wherein

R 1 in each occurrence independently is an organic moiety selected from the group consisting of:

—CH 2 —CH 2 —CH 2 —O—(CH 2 —CH 2 O—) x —(CH 2 —CH(R′)O—) y —R″,

—CH 2 —CH 2 —O—(CH 2 —CH 2 O—) x —(CH 2 —CH(R′)O—) y —R″, and

—CH 2 —R IV

where

x is from 0 to 100,

y is from 0 to 100,

R′ is methyl and

R″ in each occurrence independently is hydrogen or an alkyl group of 1 to 4 carbon atoms, a —C(O)—R′″ group where R′″=alkyl, a —CH 2 —O—R′ group, an alkylaryl group, or a —C(O)NH—R′ group,

wherein the molar fraction of oxyethylene units comprises at least 70% of the oxyalkylene units,

or the molar fraction of oxyethylene units comprises at most 70% of the oxyalkylene units and R″ is hydrogen.

4. The method according to claim 1 wherein at least 10% of the R 2 moieties are equal to R 1 .

5. The method according to claim 1 wherein R is methyl and the a/b ratio is not less than 7.

6. The method according to claim 1 wherein at least one R 1 is present and said at least one R 1 is —CH 2 —CH 2 —CH 2 —O—(CH 2 —CH 2 O—) x —(CH 2 —CH(R′)O—) y —R″ or —CH 2 —CH 2 —O—(CH 2 —CH 2 O—) x —(CH 2 —CH(R)O—) y —R″, wherein y=0 and R″ is not hydrogen.

7. A polyurethane foam obtained by a method according to claim 1 , wherein said polyurethane foam comprises said at least one siloxane of formula (I) therein.

8. The polyurethane foam according to claim 7 , wherein said polyurethane foam is closed-cell.

9. The polyurethane foam according to claim 7 , wherein the polyurethane foam is a rigid polyurethane foam, a flexible polyurethane foam, a viscoelastic foam, an HR foam, a semirigid polyurethane foam, a thermoformable polyurethane foam or an integral foam.

10. The polyurethane foam according to claim 7 wherein from 0.01% to 10% by weight of said at least one siloxane of formula (I), based on the total weight of the polyurethane foam, is present.

11. The polyurethane foam according to claim 7 wherein from 0.1% to 3% by weight of said at least one siloxane of formula (I), based on the total weight of the polyurethane foam, is present.

12. A composition of matter comprising a polyurethane foam and from 0.01% to 10% by weight of at least one siloxane of formula (I), based on the total weight of the polyurethane foam,

a in each occurrence independently is from 1 to 300,

b in each occurrence independently is from 1 to 50,

c in each occurrence independently is >0 to 4,

d in each occurrence independently is >0 to 4,

with the proviso that, per molecule of formula (I), the average number Σd of T-units and the average number Σc of Q-units per molecule are neither greater than 20, the average number Σa of D-units per molecule is not greater than 1500 and the average number Σb of R 1 -bearing siloxy units per molecule is not greater than 50,

R in each occurrence independently is one or more than one moiety selected from the group consisting of linear, cyclic or branched, aliphatic or aromatic, saturated or unsaturated hydrocarbon moieties having 1 up to 20 carbon atoms,

R 2 in each occurrence independently is R 1 or R,

R 1 is unlike R and in each occurrence independently is an organic moiety and/or a moiety selected from the group consisting of:

—CH 2 —CH 2 —CH 2 —O—(CH 2 —CH 2 O) x —(CH 2 —CH(R′)O—) y —R″

—CH 2 —CH 2 —O—(CH 2 —CH 2 O—) x —(CH 2 —CH(R′)O—) y —R″

—CH 2 —R IV

—CH 2 —CH 2 —CH 2 —O—CH 2 —CH(OH)—CH 2 OH

—CH 2 —CH 2 —CH 2 —O—CH 2 —C(CH 2 OH) 2 —CH 2 —CH 3 , where

x is from 0 to 100,

x′ is 0 or 1,

y is from 0 to 100,

R′ in each occurrence independently is an alkyl or aryl group of 1 to 12 carbon atoms, and

R″ in each occurrence independently is hydrogen or an alkyl group of 1 to 4 carbon atoms, a —C(O)—R′″ group where R′″=alkyl, a —CH 2 —O—R′ group, an alkylaryl group, or a —C(O)NH—R′ group,

R IV is a linear, cyclic or branched, including further substituted, hydrocarbon moiety having 1 to 50 carbon atoms,

R 4 in each occurrence independently is R, R 1 and/or a heteroatom-substituted, functionalized, organic, saturated or unsaturated moiety selected from the group consisting of alkyl, aryl, chloroalkyl, chloroaryl, fluoroalkyl, cyanoalkyl, acryloyloxyaryl, acryloyloxyalkyl, methacryloyloxyalkyl, methacryloyloxypropyl and vinyl,

with the proviso that at least one substituent from R 1 , R 2 and/or R 4 is other than R.