Sustainable polyester polyol compositions
Polyester polyol compositions are disclosed. The polyol compositions, which comprise recurring units of a digested thermoplastic polyester, a glycol, and castor oil, ricinoleic acid, or a mixture of castor oil and ricinoleic acid, have hydroxyl numbers within the range of 20 to 150 mg KOH/g and average hydroxyl functionalities within the range of 2.5 to 3.5. The invention includes flexible polyurethane foams that incorporate the polyester polyols. Sustainable polyester polyols made completely or in substantial part from recycled, post-industrial, and/or biorenewable materials such as polyethylene terephthalate, glycols, and castor oil are provided. The polyols have desirable properties for formulating flexible polyurethane foams and other products.
1. A polyester polyol composition comprising recurring units of:
(a) 5 to 30 wt. % of a digested thermoplastic polyester;
(b) 25 to 85 wt. % of castor oil or a mixture of castor oil and ricinoleic acid;
(c) 2 to 20 wt. % of a glycol;
(d) optionally, 2 to 30 wt. % of a dicarboxylic acid, a diester, or an anhydride, or combinations thereof; and
(e) optionally, 0.1 to 2 wt. % of glycerin;
wherein the polyol composition has a hydroxyl number within the range of 20 to 150 mg KOH/g and an average hydroxyl functionality within the range of 2.5 to 3.5.
2. The composition of claim 1 wherein the thermoplastic polyester is selected from the group consisting of polyethylene terephthalate; polybutylene terephthalate; polytrimethylene terephthalate; glycol-modified polyethylene terephthalate; copolymers of terephthalic acid and 1,4-cyclohexanedimethanol; isophthalic acid-modified copolymers of terephthalic acid and 1,4-cyclohexanedimethanol; polyhydroxy alkanoates; copolymers of diols with 2,5-furandicarboxylic acid or dialkyl 2,5-furandicarboxylates; copolymers of 2,2,4,4-tetramethyl-1,3-cyclobutanediol with isophthalic acid, terephthalic acid or orthophthalic derivatives; dihydroferulic acid polymers; and mixtures thereof.
3. The composition of claim 1 wherein the thermoplastic polyester is selected from the group consisting of virgin PET, recycled PET, and mixtures thereof.
4. The composition of claim 1 wherein the thermoplastic polyester is scrap polyethylene terephthalate recovered from automotive trunk liners, scrap polyethylene terephthalate from automotive parts dunnage, or other automotive thermoplastic polymer scrap material.
5. The composition of claim 1 comprising 8 to 20 wt. % of recurring units from recycled polyethylene terephthalate.
6. The composition of claim 1 comprising 25 to 55 wt. % of recurring units from castor oil.
7. The composition of claim 1 comprising 70 to 85 wt. % of recurring units from castor oil.
8. The composition of claim 1 comprising 4 to 15 wt. % of recurring units from diethylene glycol.
9. The composition of claim 1 having a hydroxyl number within the range of 40 to 150 mg KOH/g.
10. The composition of claim 1 having a hydroxyl number within the range of 50 to 140 mg KOH/g.
11. The composition of claim 1 having an average hydroxyl functionality within the range of 2.5 to 3.0.
12. The composition of claim 1 having an average hydroxyl functionality within the range of 2.65 to 2.90.
13. The composition of claim 1 comprising 15 to 25 wt. % of recurring units from adipic acid.
14. The composition of claim 1 comprising 20 to 30 wt. % of recurring units from ricinoleic acid.
15. A polyester polyol composition comprising recurring units of:
(a) 10 to 20 wt. % of polyethylene terephthalate;
(b) 30 to 50 wt. % of castor oil;
(c) 10 to 15 wt. % of diethylene glycol;
(d) 15 to 25 wt. % of adipic acid; and
(e) optionally, 0.1 to 2 wt.% of glycerin;
wherein the polyol composition has a hydroxyl number within the range of 40 to 75 mg KOH/g and an average hydroxyl functionality within the range of 2.7 to 3.0.
16. A polyester polyol composition comprising recurring units of:
(a) 5 to 10 wt. % of polyethylene terephthalate;
(b) 75 to 85 wt. % of castor oil;
(c) 3 to 6 wt. % of diethylene glycol;
(d) 3 to 6 wt. % of phthalic anhydride; and
(e) optionally, 0.1 to 2 wt.% of glycerin;
wherein the polyol composition has a hydroxyl number within the range of 120 to 150 mg KOH/g and an average hydroxyl functionality within the range of 2.5 to 2.8.
17. A polyester polyol composition comprising a blend of the composition of claim 1 with a polyether polyol or polymer polyol, wherein the polyether polyol or polymer polyol has a hydroxyl number within the range of 20 to 150 mg KOH/g and an average hydroxyl functionality within the range of 2.5 and 3.5.