Process for the preparation of polyricinoleic acid ester polyols having primary hydroxyl end groups

1. A process for preparing polyricinoleic acid ester polyol having primary hydroxyl end groups, comprising:

a) polycondensing ricinoleic acid until a hydroxyl number of >0 mg of KOH/g to ≦60 mg of KOH/g is reached, to form a product;

a1) reacting the product obtained in step a) with a cyclic carboxylic acid anhydride, to form a product of step a1);

b) reacting the product obtained in step a1) comprising carboxyl groups with an epoxide of formula (I):

wherein

R1 represents hydrogen, an alkyl radical or an aryl radical, with the proviso that ≧80% by weight to ≦100% by weight, based on the total amount of the epoxide of formula (I) employed, is ethylene oxide, and wherein this reaction is carried out in the presence of an amine as catalyst.

2. The process of claim 1 , wherein the cyclic carboxylic acid anhydride in step a1) is selected from the group consisting of phthalic anhydride, tetrahydrophthalic anhydride, succinic anhydride, maleic anhydride, and mixtures thereof.

3. The process of claim 1 , wherein in step b) the epoxide of formula (I) is ethylene oxide.

4. The process of claim 1 , wherein said amine catalyst is selected from the group consisting of

an amines of formula (2):

wherein

R2 and R3 independently of each other, are hydrogen, alkyl, or aryl; or

R2 and R3 together with the N atom carrying to which each is bonded form an aliphatic, unsaturated, or aromatic heterocycle;

n is an integer from 1 to 10; and

R4 is hydrogen, alkyl, or aryl, or

R4 is —(CH 2 ) x —N(R41)(R42), wherein:

R41 and R42, independently of each other, are hydrogen, alkyl, or aryl; or

R41 and R42 together with the N atom to which each is bonded form an aliphatic, unsaturated, or aromatic heterocycle; and

x is an integer from 1 to 10;

an amine of formula (3):

wherein:

R5 is hydrogen, alkyl, or aryl;

R6 and R7, independently of each other, are hydrogen, alkyl, or aryl; and

m and o, independently of each other, are an integer from 1 to 10;

(diazabicyclo[2.2.2]octane, diazabicyclo[5.4.0]undec-7-ene, dialkylbenzylamine, dimethylpiperazine, 2,2′-dimorpholinyldiethyl ether, and pyridine,

and any mixture thereof.

5. The process of claim 4 , wherein, in the amine of formula (2), R2 and R3 are methyl, R4 is hydrogen, and n=2, or R2 and R3 are methyl, R4 is —(CH 2 ) 2 —N(CH 3 ) 2 , and n=2.

6. The process of claim 4 , wherein, in the amine of formula (3), R5 is methyl, R6 and R7 are hydrogen, m=2, and o=2.

7. The process of claim 1 , wherein the reaction of step b) takes place with the epoxide of formula (I) at a temperature of from ≧70° C. to ≦150° C.

8. A polyricinoleic acid ester polyol having primary hydroxyl end groups, prepared by the process of claim 1 .

9. The polyricinoleic acid ester polyol having primary hydroxyl end groups of claim 8 , wherein said polyricinoleic acid ester polyol has an acid number of from ≧0 mg of KOH/g to ≦1 mg of KOH/g.

10. A composition comprising the polyricinoleic acid ester polyol having primary hydroxyl end groups of claim 8 and

(A2) an amine of formula (5):

wherein

R9 and R10, independently of each other, are hydrogen, alkyl, or aryl; or

R9 and R10 together with the N atom to which each is bonded form an aliphatic, unsaturated, or aromatic heterocycle;

p is an integer from 1 to 10;

R11 is hydrogen, alkyl, aryl; or —(CH 2 ) y —N(R12)(R13), wherein:

R12 and R13, independently of each other, are hydrogen, alkyl, or aryl; or

R12 and R13 together with the N atom to which each is bonded form an aliphatic, unsaturated or aromatic heterocycle; and

y is an integer from 1 to 10;

(B2) an amine of formula (6):

wherein:

R14 is hydrogen, alkyl, or aryl;

R15 and R16, independently of each other, are hydrogen, alkyl, or aryl;

r and s, independently of each other, are an integer from 1 to 10;

and/or

(C2) diazabicyclo[2.2.2]octane, diazabicyclo[5.4.0]undec-7-ene, dialkylbenzylamine, dimethylpiperazine, 2,2′-dimorpholinyldiethyl ether, and/or pyridine.

11. A polyurethane polymer obtained from the reaction of a polyricinoleic acid ester polyol of claim 8 with a polyisocyanate.

12. A flexible polyurethane foam comprising the polyurethane polymer of claim 11 .

13. A process for producing a flexible polyurethane foam having a bulk density according to DIN EN ISO 3386-1-98 in the range of from ≧10 kg/m 3 to ≦150 kg/m 3 and a compressive strength according to DIN EN ISO 3386-1-98 in the range of from ≧0.5 kPa to ≦20 kPa, at 40% deformation and the 4th cycle, comprising reacting

component A, which comprises

A1 from 50 to 95 parts by weight, based on the sum of the parts by weight of components A1 and A2, of polyether polyol;

A2 from 5 to 50 parts by weight, based on the sum of the parts by weight of components A1 and A2, of the polyricinoleic acid ester having primary hydroxyl end groups of claim 8 ,

A3 from 0.5 to 25 parts by weight, based on the sum of the parts by weight of components A1 and A2, of water and/or physical blowing agents,

A4 from 0.05 to 10 parts by weight, based on the sum of the parts by weight of components A1 and A2, of auxiliary substances and additives,

A5 from 0 to 10 parts by weight, based on the sum of the parts by weight of components A1 and A2, of compounds which contain hydrogen atoms which are reactive towards isocyanates and have a molecular weight of from 62 to 399,

with component B which comprises polyisocyanate,

wherein the production of said flexible polyurethane foam is carried out at a characteristic number of from 50 to 250 and wherein all the parts by weight stated for components A1 to A5 are standardized such that components A1 and A2 in the composition sum to 100 parts by weight.