Process for making low compression and high airflow MDI viscoelastic polyurethane foam
A reaction system comprising an organic polyisocyanate and an isocyanate reactive component for preparation of a viscoelastic polyurethane foam is provided. The isocyanate reactive component comprises (i) from 10 to 50% by weight of one or more low equivalent weight propylene oxide rich (PO-rich) polyols having a combined number average equivalent weight from 200 to 500, (ii) from 45 to 95% by weight of one or more ethylene oxide (EO-rich) polyols having a combined number average equivalent weight from 200 to 800 and an ethylene oxide content from 40% to 65% by weight of the total mass of the EO-rich polyol and at least one of (iii) from 10 to 30% by weight of one or more high equivalent weight PO-rich polyols having a number average equivalent weight from 800 to 2,000 or (iv) from 10 to 40% by weight of one or more propylene oxide co-polymer polyols containing styrene-acrylonitrile.
1. A reaction system for preparation of a viscoelastic polyurethane foam comprising:
(a) an organic polyisocyanate; and
(b) an isocyanate reactive component comprising:
(i) from 10 to up to 45% by weight of the isocyanate reactive component of one or more low equivalent weight propylene oxide rich (PO-rich) polyols having a combined number average equivalent weight from 200 to 500 and a propylene oxide content of at least 70% by weight;
(ii) from 45 to up to 80% by weight of the isocyanate reactive component of one or more ethylene oxide (EO-rich) polyols having a combined number average equivalent weight from 200 to 800 and an ethylene oxide content of at least 45% and up to 70% by weight, and the one or more EO-rich polyols having a primary hydroxyl content of at least 35% and less than 50%, based on the total hydroxyl content of the one or more EO-rich polyols;
and at least one of
(iii) from 10 to 30% by weight of the isocyanate reactive component of one or more high equivalent weight propylene oxide rich (PO-rich) polyols having a number average equivalent weight from 800 to 2,000 and a propylene oxide content of at least 70% by weight; and
(iv) from 10 to 40% by weight of the isocyanate reactive component of one or more propylene oxide co-polymer polyols containing styrene-acrylonitrile.
2. The reaction system of claim 1 , wherein the one or more EO-rich polyols have an ethylene oxide content from 45% to 60% of the total mass of the EO-rich polyol.
3. The reaction system of claim 1 , wherein the isocyanate reactive component further comprises:
(v) from 5 to 10% by weight of the isocyanate reactive component of one or more ethylene oxide-propylene oxide monols having a combined number average equivalent weight from 300 to 800.
4. The reaction system of claim 3 , wherein the isocyanate reactive component further comprises:
(vi) a chain extender.
5. The reaction system of claim 4 , further comprising:
(c) water; and
(d) a catalyst component.
6. The reaction system of claim 5 , further comprising:
(e) an organosilicone surfactant.
7. The reaction system of claim 3 , wherein the one or more ethylene oxide-propylene oxide monols have a functionality between 1 and 2 and a combined number average equivalent weight from 400 to 600.
8. The reaction system of claim 7 , wherein the one or more ethylene oxide-propylene oxide monols have an ethylene oxide concentration that is between 30-70% by weight of the total mass of the monol.
9. The reaction system of claim 1 , wherein the ethylene oxide content is from 55% to 65% by weight of the total mass of the one or more EO-rich polyols.
10. A method of preparing a viscoelastic foam, comprising:
forming reaction components, comprising:
an organic polyisocyanate;
an isocyanate reactive component comprising:
one or more low equivalent weight propylene oxide rich (PO-rich) polyols having a combined number average equivalent weight from 200 to 500, comprising from 10 to up to 45% by weight of the isocyanate reactive component, and having a propylene oxide content of at least 70% by weight;
one or more ethylene oxide (EO-rich) polyols having a combined number average equivalent weight from 200 to 800, an ethylene oxide content of at least 45% and up to 70% by weight, and comprising from 45 to up to 80% by weight of the isocyanate reactive component, and the one or more EO-rich polyols having a primary hydroxyl content of at least 35% and less than 50%, based on the total hydroxyl content of the one or more EO-rich polyols;
and at least one of
one or more high equivalent weight PO-rich polyols having a number average equivalent weight from 800 to 2,000, having a propylene oxide content of at least 70% by weight, and comprising from 10 to 30% by weight of the isocyanate reactive component; and
one or more propylene oxide co-polymer polyols containing styrene-acrylonitrile and comprising from 10 to 40% by weight of the isocyanate reactive component;
water; and
a catalyst component; and
combining the reaction components at conditions sufficient to form a viscoelastic polyurethane foam.
11. The method of claim 10 , wherein the isocyanate reactive component further comprises:
(v) from 5 to 10% by weight of the isocyanate reactive component of one or more ethylene oxide-propylene oxide monols having a combined number average equivalent weight from 300 to 800.
12. The method of claim 11 , wherein the isocyanate reactive component further comprises a chain extender.
13. The method of claim 12 , wherein the reaction components further comprises an organosilicone surfactant.
14. The method of claim 13 , wherein the one or more ethylene oxide-propylene oxide monols have a functionality between 1 and 2 and a combined number average equivalent weight from 400 to 600.
15. The method of claim 14 , wherein the one or more ethylene oxide-propylene oxide monols have an ethylene oxide concentration that is between 30-70% by weight of the total mass of the one or more monols.
16. The method of claim 15 , wherein the one or more ethylene oxide-propylene oxide monols have an ethylene oxide concentration that is between 40-60% by weight of the total mass of the one or more monols.
17. The reaction system of claim 1 , wherein the one or more EO-rich polyols have a primary hydroxyl content of at least 37% and less than 50%.
18. The reaction system of claim 17 , wherein the combined number average equivalent weight of the one or more EO-rich polyols is from 250 to 400 and the ethylene oxide content of the one or more EO-rich polyols is from 55% to 65% by weight of the total mass of the one or more EO-rich polyols.
19. The reaction system of claim 18 , wherein the isocyanate reactive component includes at least 15% and up to 35% by weight of the one or more low equivalent weight PO-rich polyols and from 45% and up to 65% by weight of the one or more EO-rich polyols.