Process for making a polyurethane foam

Patent metadata

Field	Value
Publication number	US-9814187-B2
Application number	US-201214353504-A
Country	US
Kind code	B2
Filing date	Oct 25, 2012
Priority date	Oct 28, 2011
Publication date	Nov 14, 2017
Grant date	Nov 14, 2017

Abstract

Process for making a foam suitable as plant growth medium by reacting a polyisocyanate, a polyether polyol mixture and water at an isocyanate index of 90-150 wherein the polyol mixture used comprises at least 2 polyols and wherein the polyol mixture comprises less than 50% by weight oxyethylene calculated on the weight of the polyol mixture.

First claim

The invention claimed is:

1. A plant growth medium made of a polyurethane foam having a resilience, measured according to ISO 8307, of at most 40%; a compression load deflection at 40%, measured according to ISO 3386/1, of at least 16 kPa; a free-rise core density, measured according to ISO 845, of at least 20 kg/m 3 ; and a volume increase at water saturation of at most 25% wherein the polyurethane foam is obtained from the reaction at an isocyanate index of 90-150 of:
a polyisocyanate component selected from (i) a polyisocyanate comprising diphenylmethane diisocyanate and homologues thereof having an isocyanate functionality of 3 or more wherein the amount of diphenylmethane diisocyanate, based on the total weight of the (i) polyisocyanate, is in the range of 25-70% by weight, and (ii) a prepolymer having an NCO-value of 10-30% by weight obtained from first reacting the (i) polyisocyanate and a polyol having an average molecular weight of 62-7000 and an average nominal hydroxyl functionality of 2-6;
a first polyoxyethylene polyoxypropylene polyol having an average nominal hydroxy functionality of 2-6, a number average molecular weight of 2000-12000, an oxyethylene content of more than 50% weight, based on the weight of the first polyoxyethylene polyoxypropylene polyol;
a second polyoxyethylene polyoxypropylene polyol having an average nominal hydroxy functionality of 2-6, a number average molecular weight of 2000-6000, an oxyethylene content of 20-45% by weight, based on the weight of the second polyoxyethylene polyoxypropylene polyol; and
water

wherein the weight ratio of the first polyoxyethylene polyoxypropylene polyol and the second polyoxyethylene polyoxypropylene polyol used ranges from 60:40 to 20:80.

2. The plant growth medium according to claim 1 , wherein the compression load deflection at 40%, measured according to ISO 3386/1, is at least 20 kPa, the free-rise core density, measured according to ISO 845, is 20 up to 50 kg/m 3 , the resilience, measured according to ISO 8307, is at most 30% and the volume increase at water saturation is at most 20%.

3. The plant growth medium according to claim 1 , wherein the volume of water retained in a sample of the polyurethane foam having a dimension of 100×120×75 mm, expressed as pF 0 , saturated with water and subjected to a pressure of 0 cm H 2 O column is at least 70% and wherein the volume of water retained in the sample of polyurethane foam having the dimension of 100×120×75 mm, expressed as pF 1 , saturated with water and subjected to a pressure of −10 cm H 2 O is 10-90%, wherein pF 0 and pF 1 are further defined as
pF 0 =V u /V f ×100(%)

pF 1 =V r-1 /V f ×100(%)

wherein:
V f is the volume, in ml, of the foam sample,
V u is the water uptake, in ml, of the foam sample saturated with water and subjected to a pressure of 0 cm H 2 O column for 30 min, in ml,
V r-1 is the volume of the water retained in the foam sample saturated with water and subjected to a pressure of −10 cm H 2 O column for 24 h, in ml.

4. The plant growth medium according to claim 3 , wherein pF 0 is at least 80%.

5. The plant growth medium according to claim 3 , wherein pF 1 is at least 50%.

6. Process for making a plant growth medium made of a polyurethane foam having a resilience, measured according to ISO 8307, of at most 40%; a compression load deflection at 40%, measured according to ISO 3386/1, of at least 16 kPa; a free-rise core density, measured according to ISO 845, of at least 20 kg/m 3 ; and a volume increase at water saturation of at most 25% comprising reacting at an isocyanate index of 90-150:
a polyisocyanate component selected from (i) a polyisocyanate comprising diphenylmethane diisocyanate and homologues thereof having an isocyanate functionality of 3 or more wherein the amount of diphenylmethane diisocyanate, based on the total weight of the (i) polyisocyanate, is in the range of 25-70% by weight, and (ii) a prepolymer having an NCO-value of 10-30% by weight obtained from first reacting the (i) polyisocyanate and a polyol having an average molecular weight of 62-7000 and an average nominal hydroxyl functionality of 2-6; and
a first polyoxyethylene polyoxypropylene polyol having an average nominal hydroxy functionality of 2-6, a number average molecular weight of 2000-12000, an oxyethylene content of more than 50% weight, based on the weight of the first polyoxyethylene polyoxypropylene polyol; and
a second polyoxyethylene polyoxypropylene polyol having an average nominal hydroxy functionality of 2-6, a number average molecular weight of 2000-6000, an oxyethylene content of 20-45% by weight, based on the weight of the second polyoxyethylene polyoxypropylene polyol; and
water;

wherein the weight ratio of the first polyoxyethylene polyoxypropylene polyol and the second polyoxyethylene polyoxypropylene polyol used ranges from 60:40 to 20:80.

7. The process according to claim 6 wherein the isocyanate index is 95-120.

8. The process according to claim 6 , wherein the amount of diphenylmethane diisocyanate, based on the total weight of the (i) polyisocyanate, is in the range of 25-55% by weight.

9. The process according to claim 6 , wherein the polyisocyanate component is a prepolymer having an NCO-value of 10-30% by weight and made by first reacting the (i) polyisocyanate with a polyol having a number average molecular weight of 62-7000, a number average nominal hydroxyl functionality of 2-6, and an oxyethylene content of at least 50%.

10. The process according to claim 6 , wherein the first polyoxyethylene polyoxypropylene polyol has a number average nominal hydroxy functionality of 2-4, a number average molecular weight of 2000-8000, an oxyethylene content of more than 60% weight, based on the weight of the first polyoxyethylene polyoxypropylene polyol, and wherein the second polyoxyethylene polyoxypropylene polyol has an average nominal hydroxy functionality of 2-4, a number average molecular weight of 2000-4000, an oxyethylene content of 20-35% by weight, based on the weight of the second polyoxyethylene polyoxypropylene polyol, and wherein the oxyethylene groups in the first polyoxyethylene polyoxypropylene polyol and the second polyoxyethylene polyoxypropylene polyol are randomly distributed.

11. A process according to claim 6 , wherein the total oxyethylene content of the first polyoxyethylene polyoxypropylene polyol and the second polyoxyethylene polyoxypropylene polyol is lower than 50% by weight based on the total weight of.

12. A process according to claim 6 , wherein the weight ratio of the first polyoxyethylene polyoxypropylene polyol and the second polyoxyethylene polyoxypropylene polyol ranges from 49:51 to 20:80.

13. A process according to claim 6 , wherein the first polyoxyethylene polyoxypropylene polyol and the second polyoxyethylene polyoxypropylene polyol are first mixed to form a stable dispersion of polyols and then added to the polyisocyanate component.

14. The process according to claim 13 , wherein the average weight ratio of the oxyethylene content in the stable dispersion of polyols is less than 50%, based on the weight of the stable dispersion of polyols.

15. The process according to claim 6 , wherein the polyurethane foam is prepared with at least one component selected from isocyanate-reactive chain extenders, cross-linkers having a number average molecular weight of 60-1999 and auxiliary additives other than chain extenders and cross-linkers.

16. The process according to claim 6 , wherein the foam is made in a mould with an overpack of at most 100%.

17.

Assignees

• Huntsman Int Llc

Inventors

• Macken Johan Antoine Stefaan
• Moro Loredana
• Clerinx Johannes Eduward Irene Marie Josefa
• Vandevelde Annelies

Classifications

• C08G18/10 Primary

  Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step · CPC title

• C08G18/48

  Polyethers · CPC title

• A01G24/00

  Growth substrates; Culture media; Apparatus or methods therefor (for mushrooms A01G18/20) · CPC title

• C08G18/4804

  Two or more polyethers of different physical or chemical nature · CPC title

• C08G18/4837

  and other oxyalkylene units · CPC title