WO2004113238A1

WO2004113238A1 - Spillage recovery system

Info

Publication number: WO2004113238A1
Application number: PCT/IB2004/002134
Authority: WO
Inventors: Clayton Julian Postma; Mike Fellows Smith
Original assignee: Chc Urethane Products (Pty) Ltd; Orange Diamond Absorbents (Pty) Ltd
Priority date: 2003-06-26
Filing date: 2004-06-28
Publication date: 2004-12-29

Abstract

An absorption element made from a polymer foam formed from the reaction of a first component comprising an isocyanate and a second component comprising an aromatic polyester polyol and a Mannich base polyol is disclosed. The absorption element may further comprise any combination of a fire retardant, a surfactant, a catalyst, an auxiliary blowing agent fluorocarbon and water. The absorption element is typically used for organic spillages, various types of oil spills onto roads, paved and concrete surfaces as well as soil or sand and organic spillages into storm water drains, dams, canals or rivers or into the sea or harbours, such as a fuel spill.

Description

Spillage Recovery System

BACKGROUND OF THE INVENTION

THIS invention relates to a method of treating a liquid spillage and to an absorption element usable to treat such spillages.

Currently, cleaning up of liquid spillages, such as chemical or oil spills, is largely done using peat, melt blown polypropylene, cotton waste, forest debris, sawdust, vermiculite and clay granules. Most of these materials are bulky and therefore expensive to transport to the spillage site. These materials are also relatively heavy, and peat, in particular, sinks when placed in water, so that it is not ideal for cleaning up oil spillages in water.

The ability of these materials to absorb liquid is limited. In the case of peat, forest debris, sawdust, vermiculite and clay granules it is not practical to recover the absorbed liquid from the absorbent, while a limited quantity of liquid can be recovered from the polypropylene material and cotton, typically about 50%. Thus, both systems leave a large volume of saturated material to be disposed of.

It is an object of the invention to provide an alternative method and absorption element for treating liquid spillages. SUMMARY OF THE INVENTION

According to a first aspect of the invention there is provided an absorption element made from a polymer foam formed from the reaction of:

a first component including an isocyanate; and a second component including an aromatic polyester polyol and a

Mannich base polyol.

The % mass of the aromatic polyester polyol in the second component may be in the range of 10 to 40%, preferably in the range of 25 to 35% and more preferably approximately 33%.

The % mass of the Mannich base polyol in the second component may be in the range of 10 to 40%, preferably in the range of 25 to 35% and more and is preferably approximately 33%.

The Mannich base polyol may have a hydroxyl number of from 250 to 700 and preferably has a hydroxyl number of 660.

The first and second components may be reacted together in a ratio of from 80:100 to 200:100, preferably in a ratio of from 80:100 to 120:100 and more preferably in a ratio of 88:100.

Typically the second component further includes any combination of a fire retardant, a surfactant, a catalyst, an auxiliary blowing agent fluorocarbon, and water, with the % mass of the fire retardant is in the range of 0 to 25% and preferably with the % mass of the fire retardant at approximately 15%. The fire retardant may be selected from the group consisting of tris(chloroisopropyl)phosphate, tris(dichloroisopropyl)phosphate, tris(chloro- ethyl)phosphate, and triethylphosphate. Preferably the polymer foam has a density of between 5 and 15 grams per litre.

The absorption element may be formed as a sheet, block, pad or comminuted smaller particles, preferably having a volume of 0.3 to 1 cm³.

According to a second aspect of the invention there is provided a method of forming a polymer foam, including the steps of reacting

Mannich base polyol.

Typically the second component further includes any combination of a fire retardant, a surfactant, a catalyst, an auxiliary blowing agent fluorocarbon, and water, with the % mass of the fire retardant is in the range of 0 to 25% and preferably with the % mass of the fire retardant at approximately 15%. The fire retardant may be selected from the group consisting of tris(chloroisopropyl)phosphate, tris(dichloroisopropyl)phosphate, tris(chloro- ethyl)phosphate, and triethylphosphate.

Preferably the polymer foam has a density of between 5 and 15 grams per litre.

According to a third aspect of the invention there is provided a method of treating a liquid spillage, the method comprising:

providing at least one absorption element of low density plastics foam according to the first aspect of the invention;

contacting the spillage with said at least one absorption element to absorb the liquid from the spillage; and

compressing said at least one absorption element to express the absorbed liquid.

The at least one absorption element may comprise sheets, blocks, pads or relatively small particles.

Typically, the method comprises an initial step of comminuting a polymer foam product into absorption elements of a required size. Preferably a solid tube of polymer foam is chopped into absorption elements of approximately 0.3 to 1 cm³ in volume.

The method may further comprise compressing said at least one absorption element in a set of rollers or a press to express the absorbed liquid.

The expressed liquid may be filtered for recycling.

Typically the liquid spillage is petrol, sunflower oil, vegetable oil, diesel, fuel oil, aviation fuel, engine oil, paraffin, methylene chloride, acetone or alcohol. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows a schematic diagram of a manufacturing process of foam and absorption elements according to the present invention;

Figure 2 is a graph of absorbent rates of a typical formulation of foam and absorption elements according to the present invention compared with prior art products;

Figure 3 is a graph of recovery rates of a typical formulation of the present invention compared with prior art products; and

Figure 4 is a graph of the grams spillage medium recovered per gram of absorbent of a typical formulation of foam and absorption elements according to the present invention compared with prior art products.

DESCRIPTION OF EMBODIMENTS

The method and absorption element of the present invention are designed for the treatment of liquid spillages of various kinds, including:

Organic spillages onto roads or land, such as sunflower oil from a damaged road tanker.

Various types of oil spills onto roads, paved and concrete surfaces as well as soil or sand.

Organic spillages into storm water drains, dams, canals or rivers.

Organic spillages into the sea or harbours, such as a fuel spill. Depending on the type of spill and its location, one or a number of absorption elements are added to the spillage to absorb the liquid. The saturated absorption elements according to the invention are then collected and are compressed to express the absorbed liquid, which can be recycled.

The absorption elements of the invention comprise a low-density open-cell polyurethane foam having a density of between 5 and 15 grams per litre. The foam is manufactured by reacting two pre-formulated components. The first component typically contains isocyanate and the second component of the foam is a cell opening polyol and may further include any combination of water, a surfactant, a fire retardant and auxiliary blowing agent fluorocarbon.

The isocyanate used in the first component may be any aromatic polyisocyanate. Typical aromatic polyisocyanates include m-phenylene diisocyanate, p-phenylene diisocyanate, polymethylene polyohenyl- isocyanate, 2,4-toluene diisocyanate, bitolylene diisocyanate, naphthalene- 1 ,4diisocyanate, xylene-1 ,4-diisocyanate, xylylene-1 3-diisocyanate, bis(4- isocyanotophenyl)methane, bis(3-methyl-4-isocyanatophenyl)methane, bis(3-methyl-4-isocyanatophenyl)methane, and 4,4'diphenylpropanediiso- cyanate.

Methylenebridged polyphenyl polyisocyanate mixtures are preferred as aromatic polyisocyanates and have a functionality of from 2 to about 4. These isocyanate compounds are generally produced by the phosgenation of corresponding methylene bridged polyphenyl polyamines, which are conventionally produced by the reaction of formaldehyde and primary aromatic amines, such as aniline, in the presence of hydrochloric acid and/or other acidic catalysts. US Patents Nos 2,683,730, 2,950,263, 3,012,008, 3,344,162 and 3,362,979 describe typical processes for the preparation of polyamines and methylene bridged polyphenyl polyisocyanates. Most preferred methylene-bridged polyphenyl polyisocyanate mixtures used contain approximately 20 to 100 weight percent methylene diphenyldiisocyanateisomers, with the remainder being polymethylene polyphenyl polyisocyanates having , higher functionaries and higher molecular weight. Typical of these are polyphenyl polyisocyanates mixtures containing approximately 20 to 100 weight percent methylene diphenyl diisocyanate isomers, of which 20 to about 95 weight percent thereof is the 4,4'isomer with the remainder being polymethylene polyphenyl polyisocyanates of higher molecular weight and functionality that have an average functionality of from 2.1 to about 3.5. These isocyanate mixtures are known commercially available materials and can be prepared by the process described in U.S. Patent No. 3,362,979. The most preferred isocyanate is the Dow Chemical Company's Voranate M229.

For the second component, it has been found that a Mannich polyol provides good cost performance and requires less catalyst than normal foams applied at low density, resulting in improved processing of the foam. US Patent No. 4,137,265 in the name of Texaco Development Corporation describes the preparation of suitable nitrogen containing Mannich polyols. Mannich base materials from Hydroxyl number 250 to 700 are preferred in the production of the foam, in particular Instapol (TM) which has hydroxyl number of 660. Instapol is a Mannich polyol which is available from Expanded Incorporation and has a pH value of between 9.5 and 10.5 and a viscosity at 25^°C of 53000 ± 6000 CP.

The Mannich polyol produces a foam with a fine cell structure and behaviour consistent with an open cell structure. Best results were obtained by combining the Mannich base polyol with an aromatic polyester polyol. This combination of polyols provides a foam with a very high aromatic content ensuring good chemical resistance. The chemical resistance of the foam assists in the collection and absorption of solvents and acids. The low density of the foam is responsible for providing the foam with the properties of resilience and open cell properties. This is in contrast with typical low density straight chain polyester or normal polyether foams which rapidly degrade in a chemical that is being absorbed.

Aromatic polyester polyols which have been found suitable for combination with the Mannich base polyol are polyester polyols derived from phthalic anhydride (PAA), dimethylterephthalate (DMT) or the recycling of polyethylene terephthalate (PET). Typically Expol PH 310, which is a difunctional hydroxyl terminated polyester resin of low viscosity, is used. Expol PH 310 is a product of Expanded Incorporation and has an acid value between 2 and 3 mgKOH/g and a hydroxyl number of 310 ± 20 mgKOH/g. Expol PH 310 has a viscosity of 2500 ± 500 mPa.s at 25^°C and a specific gravity of 1.22 ± 0.04 at 25^°C.

The foam according to the present invention exhibits self-extinguishing properties due to the combination of the high proportion of aromatic polyols and a Mannich base polyol, together with the inclusion of a fire retardant in the foam. It is well-known that aromatic rigid foams have a lower propensity to burn and therefore require less flame retardant to render them self-extinguishing. Fire retardants such as Tris (Chloroisopropyl) phosphate (TCPP), Tris (dichloroisopropyl) phosphate (MCPP) and Tris (chloroethyl) phosphate (TCEP), represent a group of cost effective fire retardants, which may be used in the production of the foam. Triethylphosphate (TEP) has also been found to be a suitable alternative fire retardant.

It has further been found that an inert blowing agent reduces the amount of excess isocyanate and water that is required in preparing polyurethane foam. For rigid foams, the use of water is often avoided and the extraneous blowing agent is used exclusively. The polyurethane foam according to the present invention therefore typically includes an extraneously/auxiliary added inert blowing agent such as a gas or gas producing material. Halogenated low boiling hydrocarbons i.e. having a boiling point of below 50°C, such as trichloromonofluoromethane, methylene chloride, carbon dioxide or nitrogen are used. The catalyst for the production of the polyurethane foam is preferably a tertiary amine or a mixture of amine catalysts. Suitable tertiary amines include trialkylamines (e.g. triethylamine, triethylarnine), hetrocyclic amines, such as N-alkylinorpholines (e.g., N-methylinorpholine, N-ethylmorpholine, etc) 1 ,4-dimethylpiperazine, triethylenediamine 3-dimethylaminopropyl- amine. It has been found that non-amine catalysts can also be used. Non- amine catalysts include organo metallic compounds of bismuth, lead, tin, titanium, iron, antimony, uranium, cadmium, cobalt, thorium, aluminum, mercury, zinc, nickel cerium, molybdenum, vanadium, copper manganese, zirconium. Included as examples are bismuth nitrate, lead 2- ethylhexoanate, lead benzoate, lead naphthenate, ferric chloride; a preferred organo-tin class includes the stannous salts of carboxylic acids such as stannous acetate, stannous octoate, stannous 2-ethylhexoate, 1 methyl imidizoles, stannous laurate, as well as the dialkyl tin salts of carboxylic acids such as dibutyl tin diacetate, dibutyl tin dilaurate, dibutyl tin dimaleate, dioctyl tin diacetate.

Also included in the polyurethane foam are conventional formulation ingredients such as, for example, foam stabilizers, also known as silicon oils or emulsifiers. The foam stabilizer may be an organic silane or siloxane. For example, compounds may be used having the formula: RSi [O- (R2SiO)n-(oxyalkylene)mR ]3 wherein R is an alkyl group containing from 1 to 4 carbon atoms; n is an integer of from 4 to 8; m is an integer of from 20 to 40; and ^"the oxyalkylene groups are derived from propylenene oxide and ethylene oxide. US Patent No. 3,194,773 provides more information on this.

The different components of the second component are preferably blended together, checked for suitable reactivity and stored as a storage stable blend until utilised.

The first and second components are typically reacted together in a ratio of from 80:100 to 200:100. Preferably, the first and second components are reacted in a ratio of from 80:100 to 120:100, and most preferably in a ratio of 88:100.

In preparing foam, the ingredients may be mixed with each other simultaneously and intimately by the so-called "one shot" method to provide foam by a one step process. In this instance, water should comprise at least a part of the blowing agent. In Figure 1 a diagram of a manufacturing process is shown. The first component, an isocyanate 10, and a second component, the mixture of polyols 12 are combined with a feed from an air line 14, the air line being fed by a compressed air source 16. The first component 10, second component 12 and air line 14 are combined in a spray gun 18, with the finished foam being formed after the components have passed through a static mixer 20. A solvent line 22 is used to flush the static mixer 20 after the mixer has been used. The solvent line is fed by a solvent pressure vessel 24 which is in communication with the compressed air source 16. The finished foam is comminuted into smaller particles by a shredder, typically with a volume of 0.3 to 1 cm³, after which it is moved through a hopper and bagged or placed in containers. Other methods for making suitable foams are described in U.S. Patent No. 4,087,389, the disclosure of which is incorporated herein by reference.

Typical ranges of the composition of the second component are provided below:

Range

Material Product Used % Mass

Aromatic polyester polyol (APP) 10-40 Expol 310

Mannich base polyol 10-40 Instapol NP

Fire retardant 0-25 TEP

Surfactant 0-5 Silicone B4113

Blend of catalyst 0-5 PMDETA+DMAPA

Auxiliary blowing agent fluorocarbon 0-20

Water 0-25

PMDETA is "N,N,N',N"",N""-Pentamethyl-"diethylenetriamine available from BASF Aktiengesellschaft. DMAPA is a 3-(Dimethylamino)propylamine pure also available from BASF Aktiengesellschaft. Silicone B411 B is available from Th. Goldschmidt AG and is a polyether modified polysiloxane.

The % mass of aromatic polyester in the second component is more preferably in the range of 25 to 35%, and most preferably 33%. Also, the % mass of Mannich base polyol in the second component is more preferably in the range of 25 to 35%, and most preferably 33%. The % mass of the fire retardant in the second component is preferably 15%.

Typically, one gram of foam will absorb up to 30 grams of liquid.

Depending on the application, blocks of foam can be produced in a factory environment and cut into sheets, blocks, pads or other predetermined shapes of varying sizes and thicknesses. For example, sheets can be located around bodies of water such as lakes or ponds or on grass verges, and can be placed on the ground to allow pedestrians to walk over them. In such a situation, the foam absorption elements will absorb spilt liquid from below but will protect clean-up personnel working with the spillage from coming into contact with the spilt liquid. Pads or sheets of this kind can also be used in controlled environments such as factories and other workplaces to remove contaminants from shoe soles by requiring pedestrians to walk over them, or from the tyres of vehicles by requiring vehicles to drive over them.

In a form of the invention particularly suitable for dealing with spillages into water, the polyurethane foam is produced by mixing the ingredients in a reactor and allowing the resultant foam to be produced as a continuous solid tube of approximately 150 mm diameter. The tube is then fed into a mechanical rotary cutting device having steel cutting blades which chop or comminute the foam tube into irregularly shaped particles, having an average volume of approximately 0.3 to 1 cm³. The chopped foam particles can be placed in reusable bags or tubular nets of varying diameter. Where the chopped particles are used to clean up small localised spills, the particles are conveniently stored in bags and dispensed onto the spill by opening the bags and distributing the particles onto the surface of the spilt liquid by hand. Particles are added until all of the free flowing liquid has been absorbed. The saturated foam particles are then picked up, for example by means of a shovel, and collected in bags for recovery of the liquid.

In the case of spills into rivers or dams, particles in tubular nets are first used to form booms to contain the spillage. Loose chopped foam particles from bags are then thrown on top of the spillage until the surface of the spillage is covered. Rakes, shovels and nets are then used to recover the saturated foam particles, which are collected in suitable bags for recovery.

In the case of a major spill such as a fuel oil tanker spill at sea, drums of the polyurethane components can be mixed at sea to produce the initial foam tube continuously. The resulting tube is fed continuously through a rotary cutting device, as described above, to produce the required absorbent particles. The chopped particles are blown into a large net similar to a trawlers' net, with a mesh size of approximately 5 mm, in order to retain the particles. Preferably, the net is weighted to ensure that it rests partly in the sea and partly in the spill itself.

The net is drawn through the spillage slick which is preferably contained by booms. The nets containing the oil-saturated foam particles are then dragged onto a recovery platform using winches and are passed through rollers on the recovery ship to compress the foam particles. The oil expressed from the particles is collected in storage bins together with any absorbed sea water. The recovered oil floats on the sea water and can be separated to allow the recovered water to be returned to the sea. The compressed foam and nets can be stored on a ship for later incineration. It is envisaged that such an oil recovery ship would be self-contained and would have the facility to transfer recovered oil to a waiting standby tanker. It will be appreciated that the above described embodiments are merely exemplary, and that the principles of the invention can be applied in different ways. For example, the saturated foam absorbent elements can be compressed in a hydraulic or similar press, instead of being compressed between rollers. In a suitable press, the foam elements can be compressed to approximately a one hundred and twentieth of their original volume, ensuring good recovery of the absorbed liquid and a minimised waste volume. The recovered liquid is preferably filtered to ensure that no solid particles of contaminants from the spill site, for example, soil, are collected. This also ensures that no small particles of the foam absorbent elements remain in the recovered liquid. Up to 98% of the liquid absorbed by the absorption elements can be recovered, and can be recycled.

A typical chemical formulation for the polyurethane foam is provided in Example 1 below:

Example 1 :

Material Parts Product Used

Aromatic polyester polyol (APP) 31.2 Expol 310

Mannich base polyol 31.2 Instapol NP

Fire retardant 14.3 TMCPP

Blend of catalyst 0.2 PMDETA

Auxiliary blowing agent fluorocarbon 0.1 DMAPA

Surfactant 0.1 Silicone B4113

Water 18.8

Isocyanate component 109.0 Voranate M229

Tests were conducted to compare the efficiency of this chemical formulation of the foam with peat and polypropylene, which are other materials typically used for clearing up spillages. In Figures 2, 3 and 4 the performance of the foam according to Example 1 and the other products were tested with spillages of turpentine (UN 1300), acetone (UN 1090), petrol, diesel and SAE 25W -50. It is clear from Figure 2 that the foam according to the present invention has a far higher absorbent rate than the standard absorbents. For each 1g of foam, 20g turpentine, 27g acetone, 50g petrol/fuel, 26g diesel and 16g SAE 25W -50 was absorbed. The highest absorption rate of 1g of polypropylene was 12g of SAE 25W -50. The absorption rate of peat was approximately 3g of spillage for each gram of peat.

The recovery rates of the absorbents are shown in Figure 3, with the foam of the present invention and polypropylene having similar recovery rates ranging between 60 and 80% for turpentine (UN 1300), acetone (UN 1090), petrol/fuel and diesel. For SAE 25W -50 both absorbents had a recovery rate of approximately 30%. The recovery rate of an absorbent can be defined as the % return of the amount of spillage recovered from the original spillage amount.

Figure 4 effectively combines the results of Figures 2 and 3, comparing the grams material (spillage) recovered per gram absorbent used. With the higher absorbency rate of the foam, it outperforms both peat and polypropylene, typically recovering 15 to 30 grams of spillage for each gram of absorbent. The average for polypropylene is approximately 5 grams of spillage per gram of absorbent, with peat's gram recovery rate being negligible as it has a low absorbency.

The liquid spillage is typically petrol, sunflower oil, vegetable oil, diesel, fuel oil, aviation fuel, engine oil or paraffin. The liquid spillage may also be methylene chloride, acetone, alcohol. It will be appreciated that this list of liquid spillages is not exhaustive.

A particular advantage of the present invention over existing spillage treatment systems is that the polyurethane foam absorption elements float on water, and are highly compressible, permitting excellent recovery of absorbed liquid. The high compressibility of the material also facilitates disposal of the used material. Manufacture of the foam absorption element does not deplete natural resources such as peat or other organic materials. Where the absorption elements of the invention are used to pick up organic liquids such as oil, the compressed foam absorption elements can be used as a fuel source or as an additive to asphalt road systems. Typically the cost of the foam according to the present invention and polypropylene per kilogram is in a similar range. However, due to the good absorbent rates and recovery rates of the present invention, the cost to recover a certain volume of spillage medium is typically far lower than the cost when using polypropylene or other products as the absorbent medium.

Claims

CLAIMS:

1. An absorption element made from a polymer foam formed from the reaction of:

- a first component including an isocyanate; and

- a second component including an aromatic polyester polyol and a Mannich base polyol.

2. The absorption element of claim 1 , wherein the % mass of the aromatic polyester polyol in the second component is in the range of 10 to 40%.

3. The absorption element of claim 2, wherein the % mass of the aromatic polyester polyol in the second component is in the range of 25 to 35%.

4. The absorption element of claim 3, wherein the % mass of the aromatic polyester polyol in the second component is approximately 33%.

5. The absorption element of any one of claims 1 to 4, wherein the % mass of the Mannich base polyol in the second component is in the range of 10 to 40%.

6. The absorption element of claim 5, wherein the % mass of the Mannich base polyol in the second component is in the range of 25 to 35%.

7. The absorption element of claim 6, wherein the % mass of the Mannich base polyol in the second component is approximately 33%.

8. The absorption element of any one of claims 1 to 7, wherein the Mannich base polyol has a hydroxyl number of from 250 to 700.

9. The absorption element of claim 8, wherein the Mannich base polyol has a hydroxyl number of 660.

10. The absorption element of any one of claims 1 to 9, wherein the first and second components are reacted together in a ratio of from 80:100 to 200:100.

11. The absorption element of claim 10, wherein the first and second components are reacted together in a ratio of from 80:100 to 120:100.

12. The absorption element of claim 11 , wherein the first and second components are reacted together in a ratio of 88:100.

13. The absorption element of any one of claims 1 to 12, wherein the second component further includes any combination of a fire retardant, a surfactant, a catalyst, an auxiliary blowing agent fluorocarbon, and water.

14. The absorption element of claim 13, wherein the % mass of the fire retardant in the second component is in the range of 0 to 25%.

15. The absorption element of claim 14, wherein the % mass of the fire retardant in the second component is approximately 15%.

16. The absorption element of any one of claims 13 to 15, wherein the fire retardant is selected from the group consisting of tris(chloroisopropyl)phosphate, tris(dichloroisopropyl)phosphate, tris(chloro- ethyl)phosphate, and triethylphosphate.

17. The absorption element of any one of claims 1 to 16, wherein the polymer foam has a density of between 5 and 15 grams per litre.

18. The absorption element of any one of claims 1 to 17, wherein the absorption element is formed as a sheet, block, pad or comminuted smaller particles.

19. The absorption element according to claim 18, wherein the comminuted smaller particles have a volume of 0.3 to 1 cm³ respectively.

20. A method of forming a polymer foam, including the steps of reacting

Mannich base polyol.

21. The method of forming a polymer foam of claim 20, wherein the % mass of the aromatic polyester polyol in the second component is in the range of 10 to 40%.

22. The method of forming a polymer foam of claim 21 , wherein the % mass of the aromatic polyester polyol in the second component is in the range of 25 to 35%.

23. The method of forming a polymer foam of claim 22, wherein the % mass of the aromatic polyester polyol in the second component is approximately 33%.

24. The method of forming a polymer foam of any one of claims 20 to 23, wherein the % mass of the Mannich base polyol in the second component is in the range of 10 to 40%.

25. The method of forming a polymer foam of claim 24, wherein the % mass of the Mannich base polyol in the second component is in the range of 25 to 35%.

26. The method of forming a polymer foam of claim 25, wherein the % mass of the Mannich base polyol in the second component is approximately 33%.

27. The method of forming a polymer foam of any one of claims 20 to 26, wherein the Mannich base polyol has a hydroxyl number of from 250 to 700.

28. The method of forming a polymer foam of claim 27, wherein the Mannich base polyol has a hydroxyl number of 660.

29. The method of forming a polymer foam of any one of claims 20 to 28, wherein the first and second components are reacted together in a ratio of from 80:100 to 200:100.

30. The method of forming a polymer foam of claim 29, wherein the first and second components are reacted together in a ratio of from 80:100 to 120:100.

31. The method of forming a polymer foam of claim 30, wherein the first and second components are reacted together in a ratio of 88:100.

32. The method of forming a polymer foam of any one of claims 20 to 31 , wherein the second component further includes any combination of a fire retardant, a surfactant, a catalyst, an auxiliary blowing agent fluorocarbon, and water.

33. The method of forming a polymer foam of claim 32, wherein the % mass of the fire retardant in the second component is in the range of 0 to 25%.

34. The method of forming a polymer foam of claim 33, wherein the % mass of the fire retardant in the second component is approximately 15%.

35. The method of forming a polymer foam of any one of claims 32 to 34, wherein the fire retardant is selected from the group consisting of tris(chloroisopropyl)phosphate, tris(dichloroisopropyl)phosphate, tris(chloro- ethyl)phosphate, and triethylphosphate.

36. The method of forming a polymer foam of any one of claims 20 to 35, wherein the polymer foam has a density of between 5 and 15 grams per litre.

37. A method of treating a liquid spillage, the method comprising:

providing at least one absorption element of low density plastics foam according to claims 1 to 16;

38. The method of treating a liquid spillage according to claim 37, wherein the said at least one absorption element comprises sheets, blocks, pads or relatively small particles.

39. The method of treating a liquid spillage according to claim 37 or claim 38, wherein, the method comprises an initial step of comminuting a polymer foam product into absorption elements of a required size.

40. The method of treating a liquid spillage according to claim 39, wherein a solid tube of polymer foam is chopped into absorption elements of approximately 0.3 to 1 cm³ in volume respectively.

41. The method of treating a liquid spillage according to claim 37 to 40, wherein the method comprises compressing said at least one absorption element in a set of rollers or a press to express the absorbed liquid.

42. The method of treating a liquid spillage according to claim 41 , wherein the expressed liquid may be filtered for recycling.

43. The method of treating a liquid spillage according to claim 42, wherein the liquid spillage is petrol, sunflower oil, vegetable oil, diesel, fuel oil, aviation fuel, engine oil, paraffin, methylene chloride, acetone or alcohol.