METHOD OF MOLDING RIGID POLYURETHANE FOAMS

• US 20130243986A1
• Filed: 11/30/2011
• Published: 09/19/2013
• Est. Priority Date: 12/09/2010
• Status: Abandoned Application

• Current Assignee: Dow Global Technologies LLC (Dow, Inc.)
• Original Assignee: Dow Global Technologies LLC (Dow, Inc.)
• Inventors: Pignagnoli, Francesca, Parenti, Vanni, Girotti, Cecilia
• Application Number:
  US13/879,437
• Publication Number:
  US 20130243986A1
• Time in Patent Office: Days
• US Class Current: 428/36.5
• CPC Class Codes: B29C 44/10 Applying counter-pressure during expanding
• CPC Class Codes: B29C 45/0001 characterised by the choice of material
• CPC Class Codes: C08G 18/092 oligomerisation to isocyanurate groups
• CPC Class Codes: C08G 18/14 Manufacture of cellular products
• CPC Class Codes: C08G 18/1808 having alkylene polyamine groups
• CPC Class Codes: C08G 18/1816 having carbocyclic groups
• CPC Class Codes: C08G 18/225 of alkali or alkaline earth metals
• CPC Class Codes: C08G 18/4816 mixtures of two or more polyetherpolyols having at least three hydroxy groups
• CPC Class Codes: C08G 18/4829 Polyethers containing at least three hydroxy groups C08G18/4833 - C08G18/5096 take precedence
• CPC Class Codes: C08G 2110/0025 rigid
• CPC Class Codes: C08G 2110/005 < 50kg/m3
• CPC Class Codes: C08G 2110/0083 prepared using water as the sole blowing agent
• CPC Class Codes: C08G 2115/02 to isocyanurate groups
• CPC Class Codes: Y10T 428/1376 Foam or porous material containing

Abstract

A method of making a molded rigid polyurethane foam comprising injecting into a closed mold cavity a reaction mixture at a packing factor of 1.03 to 1.9, wherein the mold cavity is under a pressure of from 300 to 950 mbar, wherein the reaction mixture comprises an organic polyisocyanate, a polyol composition, a catalyst, optionally auxiliary substances and/or additives, and a chemical blowing agent component in an amount of from 1 to 5 weight percent based on the total weight of the components excluding polyisocyanate, the chemical blowing agent component comprising at least one chemical blowing agent, wherein the chemical blowing agent component is the sole blowing agent.

Claims

1. A method of making a molded rigid polyurethane foam comprising:

injecting into a closed mold cavity a reaction mixture at a packing factor of 1.03 to 1.9, wherein the mold cavity is under a pressure of from 300 to 950 mbar, wherein the reaction mixture comprises;

a) an organic polyisocyanate;

b) a polyol composition;

c) a catalyst;

d) optionally auxiliary substances and/or additives; and

e) a chemical blowing agent component in an amount of from 1 to 5 weight percent based on the total weight of components b) to e), the chemical blowing agent component comprising at least one chemical blowing agent,

wherein the chemical blowing agent component is the sole blowing agent.

2. A method as claimed in claim 1, wherein the chemical blowing agent is water.

3. A method as claimed in claim 2, wherein the packing factor is in the range of from 1.1 to 1.5.

4. A method as claimed in claim 3, wherein the mold cavity pressure is from 0.7 to 0.9 bar.

5. A method as claimed in claim 4, wherein the foam has an applied density of from 35 to 50 kg/m³.

6. A method as claimed in claim 1, wherein component b) comprises a polyol having a functionality of from 5 to 8.

7. A method as claimed in claim 6, wherein the component b) additionally comprises at least one polyol having a functionality of from 2 to 4.

8. A method as claimed in claim 6, wherein the at least one polyol having a functionality of from 5 to 8 comprises from 35 to 65 weight percent of component b).

9. A method as claimed in claim 8, wherein the reaction mixture additionally comprises a silicone surfactant.

10. A method as claimed in claim 8, wherein the catalyst comprises at least one of a gelling catalyst, a blowing catalyst and a trimerization catalyst.

11. A method as claimed in claim 10, wherein the catalyst comprises at least two of a gelling catalyst, a blowing catalyst and a trimerization catalyst.

12. A method as claimed in claim 11, wherein the water is present in an amount of from 2.5 to 3.5 weight percent.

17. A method of making a refrigerated cabinet, a hot-water storage tank or a pipe-in-pipe insulation systems comprising the step of making a molded rigid polyurethane foam according to the method of claim 1.

13. A rigid polyurethane foam comprising the reaction product of:

a) an organic polyisocyanate;

b) a polyol composition, wherein the polyol composition comprises;

b1) a polyether polyol having a functionality of from 5 to 8

b2) a polyether polyol having a functionality of from 2 to 4;

c) at least two of a curing catalyst, a blowing catalyst and a trimerization catalyst;

d) at least one silicone surfactant; and

e) water, in an amount of from 2.5 to 3.5 weight percent based on the total weight of components b) to e),

wherein water is the sole blowing agent.

14. A foam as claimed in claim 13, wherein the polyether polyol b1) is present in an amount of from 40 to 60% by weight based on the total amount of component b).

15. A foam as claimed in claim 13, wherein the polyether polyol b2) has a functionality of from 2 to 3 and is present in an amount of from 25 to 50% by weight based on the total amount of component b).

16. A refrigerated cabinet, a hot-water storage tank or a pipe-in-pipe insulation systems comprising the foam of claim 13.