Polyols for improved viscoelastic foams with reduced temperature sensitivity

Patent metadata

Field	Value
Publication number	US-11021567-B2
Application number	US-201815918165-A
Country	US
Kind code	B2
Filing date	Mar 12, 2018
Priority date	Mar 15, 2017
Publication date	Jun 1, 2021
Grant date	Jun 1, 2021

Abstract

This invention relates to a process for preparing viscoelastic polyurethane foam in which the isocyanate-reactive component comprises a specific polyol blend, and to viscoelastic polyurethane foam wherein the isocyanate-reactive comprises the specific polyol blend. The polyol blend may be an in situ formed polyol blend.

First claim

What is claimed is:

1. A process for preparing a viscoelastic polyurethane foam comprising reacting:
(1) toluene diisocyanate,
with
(2) an isocyanate-reactive component comprising:
(a) a polyol blend having an overall hydroxyl number of from 70 mg KOH/g polyol to 110 mg KOH/g polyol, an average functionality of greater than 2, and comprising:
(i) a monofunctional polyether having a hydroxyl number of less than or equal to 56 mg KOH/g polyol, and containing less than or equal to 20% of copolymerized oxyethylene, based on the total weight of the monofunctional polyether (2)(a)(i);
(ii) a polyether polyol having a hydroxyl number of from 80 mg KOH/g polyol to 300 mg KOH/g polyol, a nominal functionality of 2, and containing from 5 to 45% of copolymerized oxyethylene, based on the total weight of said polyether polyol (2)(a)(ii);
and
(iii) a polyether polyol having a hydroxyl number of from 80 mg KOH/g polyol to 300 mg KOH/g polyol, a nominal functionality of greater than 2 to 8, and containing from 5 to 45% of copolymerized oxyethylene, based on the total weight of said polyether polyol (2)(a)(iii);
wherein (2)(a) said polyol blend comprises 20 to 50% by weight of (2)(a)(i) said monofunctional polyether and 80 to 50% by weight of components (2)(a)(ii) and (2)(a)(iii) wherein component (2)(a)(ii) is provided in an amount of 10 to 90% by weight and component (2)(a)(iii) is provided in an amount of 90 to 10% by weight, based on the total combined weight of components (2)(a)(ii) and (2)(a)(iii);

and, optionally,
(b) a polyether polyol having an average functionality of from 2 to 8, a hydroxyl number of from 20 mg KOH/g polyol to 300 mg KOH/g polyol and containing at least 50% of copolymerized oxyethylene, based on the total weight of said polyether polyol (2)(b);
wherein (2) the isocyanate-reactive component comprises (2)(a) said polyol blend in an amount of from 20% to 100% by weight and (2)(b) said polyether polyol in an amount of up to 80% by weight, with the combined weight of (2)(a) and (2)(b) totalling 100% by weight;

in the presence of
(3) a blowing agent;
(4) a catalyst;
and
(5) a surfactant;
wherein the quantity, OH number and functionality of components (2)(a)(i), (2)(a)(ii) and (2)(a)(iii) are selected such that the resultant viscoelastic foam has a ratio of the storage modulus ratio at 15° C. to the storage modulus at 30° C. of less than or equal to 4 to about 1, and wherein the resultant viscoelastic foam has a T g of less than 20° C. as measured by tan delta over a density range of from 1.0 lb/ft 3 to 6.0 lb/ft 3 at an NCO Index of greater than 95 to 110, with the proviso that when the NCO Index is greater than or equal to about 105, the isocyanate-reactive component (2) comprises at least about 3% by weight of (2)(b).

2. The process of claim 1 , wherein (2)(a) said polyol blend has a hydroxyl number of from 90 mg KOH/g polyol to 110 mg KOH/g polyol and an average functionality of at least 2.1.

3. The process of claim 1 , wherein (2)(a)(i) said monofunctional polyether has a hydroxyl number of less than or equal to 28 mg KOH/g polyol and contains at least 2% to 15% or less of copolymerized oxyethylene, based on the total weight of said monofunctional polyether (2)(a)(i); (2)(a)(ii) said polyether polyol has a hydroxyl number of from 85 mg KOH/g polyol to 240 mg KOH/g polyol and contains from 10% to 40% by weight of copolymerized oxyethylene, based on the total weight of said polyether polyol (2)(a)(ii); and (2)(a)(iii) said polyether polyol has a hydroxyl number of from 85 mg KOH/g polyol to 240 mg KOH/g polyol, a nominal functionality of 3 to 6, and contains 10% to 40% by weight of copolymerized oxyethylene, based on the total weight of said polyether polyol (2)(a)(iii).

4. The process of claim 1 , wherein (2) said isocyanate-reactive component additionally comprises at least one of:
(2)(c) a polyether polyol having an hydroxyl number of from 10 mg KOH/g polyol to 300 mg KOH/g polyol, an average functionality of from 2 to 8, and which contains from 0 to 45% by weight of copolymerized oxyethylene, based on 100% by weight of component (2)(c),
wherein polyether polyol (2)(c) is different than polyether polyols (2)(a)(ii) and (2)(a)(iii);
and/or
(2)(d) a filled polyol.

5. The process of claim 1 , wherein said polyol blend (2)(a) comprises 25 to 45% by weight of (2)(a)(i) said monofunctional polyether, and 80 to 50% by weight of components (2)(a)(ii) and (2)(a)(iii) wherein from 15 to 85% by weight comprises component (2)(a)(ii) and from 85% to 15% by weight comprises component (2)(a)(iii).

6. The process of claim 1 , wherein the relative amounts of (2)(a) and (2)(b) are 85% to 99% by weight of (2)(a) and 15% to 1% by weight of (2)(b), wherein the %'s by weight of (2)(a) and (2)(b) are based on 100% by weight of the combined weight of components (2)(a) and (2)(b).

7. The process of claim 1 , wherein (2)(b) said polyether polyol has a hydroxyl number of 30 mg KOH/g polyol to 170 mg KOH/g polyol, an average functionality of 2.5 to 6, and contains 50% to 99% by weight of copolymerized oxyethylene, based on 100% by weight of component (2)(b).

8. The process of claim 1 , wherein (2)(a) said polyol blend is formed in-situ and prepared by:
A) introducing into a reaction vessel a mixture comprising:
(1) an initial starter (S i ) comprising a monofunctional compound having a hydroxyl number of less than 56 mg KOH/g polyol,
and
(2) a DMC (double metal cyanide) catalyst,

B) feeding
(1) an epoxide comprising propylene oxide and ethylene oxide in a weight ratio of from 100:0 to 20:80,
into the reaction vessel;

C) allowing said epoxide mixture and said initial starter (S i ) to react and continuing to polymerize by feeding the epoxide until the equivalent weight of said monofunctional compound is increased by at least 10% by weight and reaches a value between about 1,500 and about 6,000;
D) continuously adding
(1) a low molecular weight starter (S c ) having a nominal functionality of greater than 2 to 6, and an equivalent weight of 28 to 400 into the reaction vessel while continuing to feed epoxide;

E) completing addition of the continuous starter (S c );
and
F) allowing the mixture to continue polymerizing in the reaction vessel thereby forming
(2)(a) an in-situ formed polyol blend which has an overall hydroxyl number of from 70 mg KOH/g polyol to 110 mg KOH/g polyol, an average functionality of greater than 2, and which comprises
(i) a monofunctional polyether having a hydroxyl number of less than or equal to 56 mg KOH/g polyol, and containing less than or equal to 20% by weight of copolymerized oxyethylene, based on 100% by weight of said monofunctional polyether (2)(a)(i);
(ii) a polyether polyol having a hydroxyl number of 80 mg KOH/g polyol to 300 mg KOH/g polyol, a nominal functionality of 2 and containing from 5 to 45% by weight of copolymerized oxyethylene, based on the total weight of said polyether polyol (2)(a)(ii);
and
(iii) a polyether polyol having a hydroxyl number of 80 mg KOH/g polyol to 300 mg KOH/g polyol, a nominal functionality of greater than 2 to 8, and containing from 5 to 45% by weight of copolymerized oxyethylene, based on the total weight of said polyether polyol (2)(a)(iii);

wherein (2)(a) said polyol blend comprises 20 to 50% by weight of (2)(a)(i) said monofunctional polyether and 80 to 50% by weight of components (2)(a)(ii) and (2)(a)(iii) wherein from 10 to 90% by weight comprises component (2)(a)(ii) and from 90 to 10% by weight comprises component (2)(a)(iii);

and, optionally,
(II) combining said in-situ formed polyol blend (2)(a) with
(2)(b) up to 80% by weight, based on 100% by weight of components (2)(a) and (2)(b), of a polyether polyol having an average functionali

Assignees

• Covestro Llc

Inventors

• Barksby Nigel
• Neal Brian L
• Mcvey Susan B
• Hayes John E

Classifications

• C08G18/637

  characterised by the in situ polymerisation of the compounds having carbon-to-carbon double bonds in a reaction mixture of saturated polymers and isocyanates · CPC title

• C08G2110/0008

  flexible · CPC title

• C08G2280/00

  Compositions for creating shape memory · CPC title

• C08J2203/142

  Halogenated saturated hydrocarbons, e.g. H3C-CF3 · CPC title

• C08G18/7621 Primary

  being toluene diisocyanate including isomer mixtures · CPC title