WO2011069203A1

WO2011069203A1 - Blowing agents for foams

Info

Publication number: WO2011069203A1
Application number: PCT/AU2010/001664
Authority: WO
Inventors: Barry Branscombe Walker
Original assignee: Barry Branscombe Walker
Priority date: 2009-12-08
Filing date: 2010-12-08
Publication date: 2011-06-16
Also published as: AU2010330691A1

Abstract

This invention relates to environmentally acceptable foaming or blowing agents for preparing polymeric foams and to articles made from such foams. In particular the invention relates to compositions for use as foaming or blowing agents that comprise dichloroethylene and a suitable fluorinated ether or preferably an alkoxy substituted perfluoro compound. Highly suitable compositions include trans- 1,2-dichloroethylene and 1-ethoxy-nonafluorobutane. The compositions also show unexepected compressive strength properties.

Description

BLOWING AGENTS FOR FOAMS

FIELD OF THE INVENTION

This invention relates to environmentally acceptable foaming or blowing agents for preparing polymeric foams and to articles made from such foams. In particular the invention relates to compositions for use as foaming or blowing agents that comprise 1,2-dichloroethylene and a suitable fluorinated ether or preferably an alkoxy substituted perfluoro compound. BACKGROUND OF THE INVENTION

Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field. Polyurethane foams can take many forms, but they are generally divided into two major groups: flexible foams and rigid foams.

Flexible polyurethane foams are useful in the manufacture of articles of furniture where their resilience makes them suitable for incorporation in cushions and mattresses. These foams are characterised by a cell structure that is essentially open, permitting the free passage of gas through the structure of the foam. Consequently, flexible polyurethane foams have insulation properties inferior to those of rigid closed cell foams. Rigid polyurethane foams have particular application where low densities combined with high levels of thermal insulation are required. Such properties are characteristic of closed cell foams. The rigid closed cell foams have a fine cellular structure that frequently preserves some of the foaming agent within the cells. While many types of insulating materials rely upon the entrapment of air, closed cell foams can have enhanced insulating properties where the foaming agent employed has a low coefficient of thermal conductivity or other properties that may enhance the insulating performance of the foam. Rigid polyurethane foams are commonly prepared by reacting two separate component mixtures that are generally liquids at room temperature, even though they may contain minor quantities of dissolved substances that are normally gases at room temperature. An example of such a gas is 1,1,1,2-tetrafluoroethane, or HFC 134a which has a boiling point of approximately -26.2 degrees Celsius but which, when added as a minor component, does not substantially reduce the boiling point of the mixture.

Polyurethanes are materials formed by the reaction of a polyisocyanate with a polyalcohol, or polyol, in the presence of a catalyst and other additives. A polyisocyanate is a molecule with two or more isocyanate functional groups, and a polyol is a molecule with two or more hydroxyl functional groups. The product of the reaction is a polymer containing a urethane linkage.

A nomenclature used in identifying the reaction components refers to the component containing predominantly isocyanates as the "A side" and the component containing predominantly polyols the "B side". The blowing or foaming agent may be added to either or both sides, but it is more customary to include it in the B side. Small additions of water may be added to the B side or at the time of mixing.

When the A and B sides are combined in an exact ratio, the components react and generate heat, causing gases entrained within the liquid components to nucleate and form cells. If water is present, it reacts with isocyanate to liberate carbon dioxide. With the increase in temperature, the blowing agent or agents form gases through mechanisms including dissolution, evaporation and boiling. Gases thus liberated combine to expand the cells while the mixture remains a liquid. As the polymerisation reaction proceeds, the cell walls become rigid, trapping some of the gases within the cells.

It is a feature of rigid polyurethane foams used for the purpose of thermal insulation that the structure ideally consists of a framework of polymeric material surrounding entrapped gases. The cells are predominantly closed such that the entrapped gases are held for a considerable period of time within the structure. The period for which the gases are held within the cells is dependent upon a number of factors including the permeability of the polymeric material to the gases, the pressure of gas within the cells and the temperature to which the rigid foam is exposed.

The physical and chemical properties taken into consideration in the selection of blowing agents include boiling point, stability, solvency, compatibility with premix components, surface tension, vapour phase thermal conductivity, flammability and enthalpy of vaporisation. However, environmental considerations such as Ozone Depleting Potential (ODP) and Global Warming Potential (GWP) have increasingly become factors in the selection of blowing agents.

Historically, the chlorofluorocarbons, or CFCs, were found to be excellent blowing or foaming agents. However, their implication in the destruction of tropospheric ozone led to international action under the Montreal Protocol to cease manufacture according to an agreed timetable. The phaseout of the CFCs in developed countries in the 1990s triggered a search for suitable alternatives. While some manufacturers selected hydrocarbon foaming agents despite flammability and performance shortcomings, many preferred the alternative dichlorofluoroethane, or HCFC-141b, sometimes in combination with chlorodifluoromethane, or HCFC-22. As HCFC- 141b, HCFC-22 and the other HCFCs are now being phased out under the provisions of the Montreal Protocol, there has been a renewed search for alternative blowing or foaming agents. In seeking alternatives, the fluorocarbon manufacturers initially concentrated their efforts on research into the use of hydrofluorocarbons (HFCs) as foaming agents and the result has been the evolution of products incorporating HFCs either singly or as mixtures. The now common refrigerant HFC- 134a has been used for some time, particularly in applications where the foam is applied by spray. Where an "in-kind" replacement for HCFC- 141b is required, mixtures containing combinations of HFC-245fa, HFC-365mfc and HFC-227ea are marketed as commercial products. However, despite posing no threat to tropospheric ozone, the HFC alternatives all have global warming potentials greater than 900 times that of carbon dioxide. The HFCs are described under the Kyoto Protocol as "synthetic greenhouse gases" and it is probable that their use will come under progressively increasing restrictions as governments act to limit the release of greenhouse gases. Being particularly powerful greenhouse gases, the HFCs are likely to be among the first considered for regulatory controls. Consequently, there remains a need for an alternative with a relatively low global warming potential.

One alternative that meets many of the requirements for a foaming agent or blowing agent are the 1,2-dichloroethylenes, in particular trans- 1,2-dichloroethylene, or TDCE. Trans- 1,2-dichloroethylene is well known as a powerful solvent. A liquid at room temperature (boiling point 48°C), it does not deplete the ozone layer and has a global warming potential close to zero because of its very short atmospheric lifetime. Under the US EPA's Significant New Alternatives Program, TDCE was approved in 2005 as a replacement for CFCs and HCFCs in rigid polyurethane foams. There are two factors limiting its broad adoption. One is that, unlike HCFC-141b which has no flash point, TDCE has a flash point of about 2°C. The existence of a flash point imposes a restriction on its ease of use as it generally necessitates special provisions for storage and transport. The other factor is that trans- 1,2-dichloroethylene is a powerful solvent and such substances are known to cause softening in the structure of polyurethane foams resulting in poor compressive strengths. It is commonly understood by formulators of rigid polyurethane foams that the incorporation of high levels of powerful solvents leads to foams of poor compressive strength. For this reason, trans- 1,2-dichloroethylene has not formerly been contemplated for use as the major blowing or foaming agent in a foam composition.

US2005009932 describes the use of trans- 1,2-dichloroethylene to improve the processability of foam compositions. EP 1471101 describes the use of trans-1,2- dichloroethylene as a means of improving the fire resistance of resultant foams. In these and other cases where trans- 1,2-dichloroethylene is used in foam compositions, its application is that of an additive.

Therefore there remains a need for providing for foaming or blowing agents suitable for polymeric foams that comprise 1,2-dichloroethylenes like TDCE and yet have suppressed flash points.

WO2007008278 describes the use of 1-methoxy nonafluorobutane to modify the flash point of trans- 1,2-dichloroethylene. When selecting a material for use in the suppression of the flash point of another material by combining one with the other, the selection of a flash point suppressant with minimal flammability characteristics would be preferable. It follows that the selection of 1-methoxy nonafluorobutane, which has no lower flammability limit when tested in accordance with ASTM E681-94 and no upper flammability limit when tested in accordance with ASTM E681-94, would be preferable to other alkoxy substituted perfluoro compounds, e.g. 1-ethoxy nonafluorobutane which has a lower flammability limit of 210 g/m 3 and an upper flammability limit of 1070 g/m 3 when tested in accordance with the same standards.

In spite of the aforesaid discussion there remains a need for a blowing or foaming agent that is a solvent or a solvent mixture that has little flammability, a low or minimal flash point and low or minimal global warming potential compared to conventional industry solvents.

It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative. The Applicant has now surprisingly discovered that fluorinated ethers are effective at suppressing the flash point of 1,2-dichloroethylene. The present invention can thus provide for compositions wherein 1,2-dichloroethylenes, in particular trans- 1,2- dichloroethylene is used as the major blowing agent. This was hitherto unknown. In particular compositions comprising trans- 1,2-dichloroethylene and 1-ethoxy - nonafluorobutane are unknown.

Even more surprisingly and unexpectedly, despite expectations of poor compressive strengths, it has been discovered that, the compressive strengths of foams prepared from blowing agents comprising 1,2-dichloroethylenes like trans- 1,2- dichloroethylene are within the range expected of foams produced with the aid of commonly used commercial blowing agents without the disadvantages of the commercial blowing agents. SUMMARY OF THE INVENTION

In a first aspect, the present invention provides a composition for use as a foaming or blowing agent comprising a mixture of 1,2-dichloroethylene and a fluorinated ether, said ether capable of lowering the flash point of 1,2-dichloroethylene and present in a flash point lowering amount.

Preferably the 1,2-dichloroethylene is trans- 1,2-dichloroethylene. Preferably the ether is capable of minimising the flash point of trans- 1,2-dichloroethylene and is present in a flash point minimising amount. More preferably the ether is a flash point eliminating ether and is present in a flash point eliminating amount.

Preferably the flash point is lowered such that it is not measurable.

A suitable amount of fluorinated ether is required to be added to trans- 1,2- dichloroethylene in order to minimise the flash point. Preferably the amount is at least 1%, more preferably it is at least 5% and in the most preferred embodiments does not exceed 20% of the composition. In most preferred embodiments, the fluorinated ether is about 3% to about 6% of the composition. Preferably the fluorinated ether is an alkoxy substituted perfluoro compound.

Preferably the composition for use as a foaming or blowing agent comprises a mixture of trans- 1,2-dichloroethylene and a fluorinated ether that is 1-ethoxy- nonafluorobutane and is capable of minimising the flash point of 1,2-dichloroethylene. An example of a 1-ethoxy-nonafluorobutane is HFE-7200 from 3M.

When the fluorinated ether is 1-ethoxy-nonafluorobutane, other fluorinated ethers may additionally be present but should not exceed 50% of the total amount of fluorinated ether. Preferably the amount is not more than 30% and most preferably the amount is not more than 10%. An example of an additional fluorinated ether is 1- methoxy-nonafluorobutane. In a second aspect, the present invention provides a composition for use as a foaming or blowing agent comprising a mixture of 1,2-dichloroethylene and an alkoxy substituted perfluoro compound, said perfluoro compound capable of lowering the flash point of 1,2-dichloroethylene.

Preferably the alkoxy substituted perfluoro compound is capable of minimising the flash point of 1,2-dichloroethylene and is present in a flash point minimising amount. More preferably the alkoxy substituted perfluoro compound is a flash point eliminating ether and is present in a flash point eliminating amount.

Preferably the flash point is lowered such that it is not measurable.

Preferably the alkoxy substituted perfluoro compound is present in an amount of at least 1%, more preferably it is at least 5% and in the most preferred embodiments does not exceed 20%. In most preferred embodiments, the alkoxy substituted perfluoro compound is about 3% to about 6% of the composition.

Preferably the 1,2-dichloroethylene is trans- 1,2-dichloroethylene and an alkoxy substituted perfluoro compound is l-ethoxy-nonafluorobutane.

When the alkoxy substituted perfluoro compound is l-ethoxy-nonafluorobutane, other alkoxy substituted perfluoro compounds may additionally be present but should not exceed 50% of the total amount of alkoxy substituted perfluoro compounds. Preferably the amount is not more than 30% and most preferably the amount is not more than 10%. An example of an additional alkoxy substituted perfluoro compound is 1- methoxy-nonafluorobutane.

In a third aspect, the present invention provides a composition for use as a foaming or blowing agent comprising a mixture of trans- 1,2-dichloroethylene and a fluorinated ether that is l-ethoxy-nonafluorobutane, said l-ethoxy-nonafluorobutane capable of minimising the flash point of 1,2-dichloroethylene. Preferably the 1-ethoxy-nonafluorobutane is capable of minimising the flash point of 1,2-dichloroethylene and is present in a flash point minimising amount. More preferably the 1-ethoxy-nonafluorobutane is a flash point eliminating ether and is present in a flash point eliminating amount.

Preferably the flash point is lowered such that it is not measurable.

Preferably the 1-ethoxy-nonafluorobutane is present in an amount of at least 1%, more preferably it is at least 5% and in the most preferred embodiments does not exceed 20%. In most preferred embodiments, the 1-ethoxy-nonafluorobutane is about 3% to about 6% of the composition.

Other fluorinated ethers may additionally be present but should not exceed 50% of the total amount of fluorinated ether. Preferably the amount is not more than 30% and most preferably the amount is not more than 10%. An example of an additional fluorinated ether is 1-methoxy-nonafluorobutane.

In a fourth aspect, the present invention provides a composition for use as a foaming or blowing agent comprising a mixture of 1,2-dichloroethylene and a fluorinated ether, said ether capable of lowering the flash point of 1,2-dichloroethylene and present in a flash point lowering amount and wherein a polymeric foam prepared from said foaming or blowing agent has an improved compressive strength.

Preferably the 1,2-dichloroethylene is TDCE and the fluorinated ether is 1- methoxy-nonafluorobutane or 1-ethoxy-nonafluorobutane.

In a fifth aspect, the present invention provides a composition for use as a foaming or blowing agent comprising a mixture of 1,2-dichloroethylene and an alkoxy substituted perfluoro compound, said perfluoro compound capable of lowering the flash point of 1,2-dichloroethylene and wherein a polymeric foam prepared from said foaming or blowing agent has an improved compressive strength. Preferably the 1,2-dichloroethylene is TDCE and the alkoxy substituted perfluoro compound is 1-methoxy-nonafluorobutane or 1-ethoxy-nonafluorobutane.

In a sixth aspect, the present invention provides a composition for use as a foaming or blowing agent comprising a mixture of trans 1,2-dichloroethylene and 1- ethoxy-nonafluorobutane, said 1-ethoxy-nonafluorobutane capable of lowering the flash point of 1,2-dichloroethylene and wherein a polymeric foam prepared from said foaming or blowing agent has an improved compressive strength. In a seventh aspect the present invention provides for use of a foaming or blowing agent comprising a mixture of 1,2-dichloroethylene and a fluorinated ether, said ether capable of lowering the flash point of 1,2-dichloroethylene and present in a flash point lowering amount in the preparation of a foam. Preferably the fluorinated ether is an alkoxy substituted perfluoro compound.

More preferably the 1,2-dichloroethylene is TDCE and the alkoxy substituted perfluoro compound is l-methoxy-nonafluorobutane or 1-ethoxy-nonafluorobutane. Preferably the foam has an improved compressive strength.

When the fluorinated ether is 1-ethoxy-nonafluorobutane, other fluorinated ethers may additionally be present but should not exceed 50% of the total amount of fluorinated ether. Preferably the amount is more than 30% and most preferably the amount is not more than 10%. A suitable additional fluorinated ether is l-methoxy- nonafluorobutane .

In an eighth aspect, the present invention provides a composition for preparing a polymeric foam comprising a mixture of 1,2-dichloroethylene and a fluorinated ether, said ether capable of lowering the flash point of 1,2-dichloroethylene.

Preferably the fluorinated ether is an alkoxy substituted perfluoro compound. Preferably the 1,2-dichloroethylene is trans- 1,2-dichloroethylene and the alkoxy substituted perfluoro compound is 1-ethoxy-nonafluorobutane. Preferably the polymeric foam is a polyurethane foam that is a rigid closed cell foam. In a ninth aspect the invention relates to a process of preparing a polymeric foam comprising reacting a foamable composition comprising a mixture of 1,2- dichloroethylene and a fluorinated ether, said ether capable of lowering the flash point of 1,2-dichloroethylene with one or more polymers or one or more compounds capable of forming a polymer to form a foam or cellular structure. Preferably the foam is a rigid closed cell foam.

Preferably the process comprises the steps of preparing polyurethane or poiyisocyanurate foams by combining an isocyanate, a polyol or mixture of polyols, the composition of the invention, and other materials as required including catalysts, surfactants, colourants and the like.

In a tenth aspect the invention provides a blown or polymeric foam prepared from the composition according to the invention. Preferably the polymeric foam is a polyurethane foam that is a rigid closed cell foam and is prepared by the process of the invention. More preferably the foam comprises small amounts of a blowing or foaming agent according to the invention contained within the cells. Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to". DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to compositions for use as a foaming agent that have little flammability, a low or minimal flash point and low or minimal global warming potential. While the term blowing agent may be said to refer to agents that have a role in filling polymeric cells with gas and the foaming agent to one that initiates form formation, the terms "blowing agent" and "foaming agent" are often used interchangeably and are therefore used in a similar manner throughout the specification.

The compositions comprise at least 1,2-dichloroethylene and a fluorinated ether that is capable of minimising the flash point of 1,2-dichloroethylene. In preferred embodiments this mixture comprises 1,2-trans-dichloroethylene (TDCE) and a fluorinated ether that is an alkoxy substituted perfluro compound. A highly preferred alkoxy substituted perfluro compound is 1-ethoxy-nonafluorobutane. An example of a 1-ethoxy-nonafluorobutane is HFE-7200 from 3M. As is known, HFE-7200 from 3M consists of two inseparable isomers with essentially identical properties, (CF3)2CFCF20C2H5 (CAS No. 163702-06-5) and CF3CF2CF2CF20C2H5 (CAS No. 163702-05-4).

Fluorinated ethers like HFE-7200 are advantageously used in the invention as they are not classed as a hazardous substance, so its use introduces no additional occupational health and safety concerns. Further it has minimal ozone depleting potential and a global warming potential 55 times that of carbon dioxide, which is not high when compared with many commercially available fluorinated hydrocarbons. Like TDCE, its time weighted average (TWA) exposure limit is 200 ppm.

A suitable amount of fluorinated ether is required to be added to 1,2-trans- dichloroethylene in order to minimise the flash point such that it is not measurable. Preferably the amount is at least 1%, more preferably it is at least 5% and in the most preferred embodiments does not exceed 20%. Ideally an amount of from about 3% to about 10% is advantageous for the invention. While not critical, the amount is generally v/v of the composition.

Preferably the fluorinated ether is an alkoxy substituted perfluro compound. Preferably the alkoxy substituted perfluro compound is 1 -ethoxy - nonafluorobutane .

Ideally an amount of l-ethoxy-nonafluorobutane from about 3% to about 10% is sufficient for the invention. An amount of as little as 3% to about 6% of the l-ethoxy- nonafluorobutane is also advantageous. At a ratio of 5% by volume to 95% by volume trans- 1,2-dichloroethylene, l-ethoxy-nonafluorobutane exhibits flash point suppression such that when tested no flash point was measured and no sustained burning was detected, l-ethoxy-nonafluorobutane is therefore effective at suppressing the flash point of trans- 1,2-dichloroethylene when tested in accordance with ASTM D93 and ASTM D 4206.

While a mixture of fluorinated ethers may be present, it is preferred that the fluorinated ether is largely l-ethoxy-nonafluorobutane. A reason for a preference for 1- ethoxy nonafluorobutane over 1-methoxy nonafluorobutane is their relative environmental impact. Neither of the substances has an Ozone Depletion Potential (ODP) and neither is considered to be a Volatile Organic Compound (VOC). The two substances differ substantially in their atmospheric lifetimes, with 1-methoxy nonafluorobutane having an atmospheric lifetime of 4.1 years and 1 -ethoxy nonafluorobutane having an atmospheric lifetime of 0.8 years. In addition, 1-methoxy nonafluorobutane has a GWP of 320 while 1-ethoxynonafluorobutane has a GWP of 55. As the environmental fate of blowing agents involves predominantly their release to the atmosphere as gases, it follows that the use of 1-ethoxynonafluoropropane is preferable. When other ethers, e.g. 1-methoxy-nonafluorobutane (HFE-7100) are present in the composition, preferably the amount of such ethers should not exceed 50%. More preferably the amount is not more than 30% and most preferably the amount is not more than 10%. It may be necessary in some circumstances to lower the boiling point by the addition of a small quantity of a lower boiling point fluid. While many of the fluorocarbon refrigerants would perform this function, it would be preferable to use a fluid that does not introduce a penalty with respect to environmental acceptability. An example of such fluids is low boiling hydrocarbon compounds that may be advantageously added to the compositions of the invention. Preferably these compounds are non-halogenated. Examples include carbon dioxide, ethers like dimethyl ether and C1-C4 alkanes with butane being the fluid of choice. As dimethyl ether and the alkanes tend to be flammable, an additional quantity of 1-ethoxy-nonafluorobutane may be added if required. An alternative would be to use additional water in the blended foaming composition provided the thermal and mechanical properties of the final polyurethane product are not compromised. A small amount of other ingredients commonly employed with foaming or blowing agents prior to their use may be added without departing from the scope of the invention.

Despite expectations of poor compressive strengths, it has been discovered that surprisingly, the compressive strengths of foams blown with compositions of the present invention are within the range expected of foams produced with the aid of the commonly used commercial blowing agents. Further foams produced using TDCE as the principal blowing agent have higher compressive strengths than would have been expected for such a powerful solvent.

Compositions for use as a foaming or blowing agent including a mixture of 1,2- dichloroethylene and a fluorinated ether, wherein the ether is capable of lowering the flash point of 1,2-dichloroethylene and present in a flash point lowering amount can be used to prepare polymeric foams with an improved compressive strength.

In preferred embodiments the 1,2-dichloroethylene is trans- 1,2-dichloroethylene and the fluorinated ether is an alkoxy substituted perfluoro compound.

The fluorinated ether can also be comprised of 1-methoxy-nonafluorobutane or 1- ethoxy-nonafluorobutane or mixtures thereof, the 1-methoxy-nonafluorobutane or 1- ethoxy-nonafluorobutane or the mixture thereof being capable of minimising the flash point of 1,2-dichloroethylene. When the fluorinated ether is 1-ethoxy-nonafhiorobutane it is present in an amount of at least 1 %, preferably at least 5% and preferably not greater than about 20%. Ideally the amount is about 3 % to about 6%. With regard to the compressive strength of the foams produced from such compositions, as an example, a rigid polyurethane foam blown using a blend of 19% trans- 1,2-dichloroethylene and 1% 1-ethoxy nonafluorobutane as the blowing agent has an average compressive strength of 145 kPa and a density of 32.5 kg/m . The invention also relates to all foams, (including but not limited to closed cell foam, open cell foam, rigid foam, flexible foam, integral skin and the like) prepared from a polymer foam formulation comprising a composition according to the invention.

Thus, the compositions previously described can also be used to make polymeric foams. A composition for preparing a polymeric foam may include a mixture of 1,2- dichloroethylene and a fluorinated ether, with the ether being capable of lowering the flash point of 1,2-dichloroethylene.

In particularly preferred embodiments, the 1,2-dichloroethylene is trans- 1,2- dichloroethylene and the fluorinated ether is l-ethoxy-nonafluorobutane. In preferred embodiments, the polymeric foam is a polyurethane foam that is a rigid closed cell foam.

The invention therefore also relates to use of a foaming or blowing agent including a mixture of 1,2-dichloroethylene and a fluorinated ether, wherein the ether is capable of lowering the flash point of 1,2-dichloroethylene and is present in a flash point lowering amount in the preparation of a foam. Such foams have an improved compressive strength. In the methods of the invention, a foaming or blowing agent including a mixture of 1,2-dichloroethylene and a fluorinated ether is used to prepare a foam. These foams have improved compressive strength.

The foamable or foam forming composition of the invention may be foamed by known methods. In this regard the foaming or blowing agent undergoes volumetric expansion as required. The type of foams includes those well known in the art, including thermosetting foams, thermoplastic foams and foams prepared in-situ. The present invention also relates to the use of the compositions of the invention in conventional foaming equipment, such as polyurethane foaming equipment, at conventional processing conditions. The present methods therefore include masterbatch type operations, blending type operations, third stream blowing agent addition, and blowing agent addition at the foam head.

Preferably the 1,2-dichloroethylene is trans- 1,2-dichloroethylene and the fluorinated ether is a alkoxy substituted perfluoro compound. In most preferred embodiments, the 1,2-dichloroethylene is trans- 1,2-dichloroethylene and the fluorinated ether is 1-methoxy-nonafluorobutane or l-ethoxy-nonafluorobutane or their mixtures thereof. In some embodiments the fluorinated ether is largely l-ethoxy- nonafluorobutane though not more than 50%, preferably not more than 30%, more preferably not more than 10% l-methoxy-nonafluorobutane may be present.

Preferably the amount of the fluorinated ether is at least 1%, more preferably it is at least 5% and in the most preferred embodiments does not exceed 20% of the composition. In most preferred embodiments, the fluorinated ether is about 3% to about 6% of the composition.

A process of preparing a polymeric foam includes the steps of reacting a foamable composition including a mixture of 1,2-dichloroethylene and a fluorinated ether. The ether is capable of lowering the flash point of 1,2-dichloroethylene with one or more polymers or one or more compounds capable of forming a polymer to form a foam or cellular structure. Preferably the foam is a rigid closed cell foam. In the process according the steps of preparing polyurethane or polyisocyanurate foams includes combining an isocyanate, a polyol or mixture of polyols, any of the the compositions as described above and other materials as required including catalysts, surfactants, colourants and the like.

The fluorinated ether is present in an amount of at least 1 %, preferably at least 5% and preferably not greater than about 20%. Ideally the amount is about 3 % to about 6%. Preferably the 1,2-dichloroethylene is trans- 1,2-dichloroethylene and the fluorinated ether is an alkoxy substituted perfluoro compound. Most preferably, the 1,2-dichloroethylene is trans- 1,2-dichloroethylene and the fluorinated ether is 1-ethoxy- nonafluorobutane . When the fluorinated ether is l-ethoxy-nonafluorobutane, other fluorinated ethers may additionally be present but should not exceed 50% of the total amount of fluorinated ether. Preferably the amount is more than 30% and most preferably the amount is not more than 10%. A suitable additional fluorinated ether is 1-methoxy- nonafluorobutane .

Blown or polymeric foams are prepared from compositions of the invention as described above. Such foams include polyurethane foam which is a rigid closed cell foam and is prepared by the process of the invention. Small amounts of a composition according to the invention may be contained within the cells.

The invention is directed in particular to polyurethane and polyisocyanurate foams. The methods generally comprise adding the blowing or foaming agent of the present invention to a foamable composition, and reacting the foamable composition with one or more polymers or one or more compounds capable of forming a polymer to form a foam or cellular structure, in particular a rigid closed cell foam. In general, such preferred methods comprise preparing polyurethane or polyisocyanurate foams by combining an isocyanate, a polyol or mixture of polyols, the blowing or foaming agent of the invention, and other materials as required including catalysts, colourants and the like.

Rigid polyurethane products are supplied generally in the form of two liquid components which are mixed in a precise ratio to produce a foam which expands and then cures to a stable low density mass. The "A" component generally is formulated with polymeric isocyanates containing reactive isocyanate groups while the "B" component contains polyols, catalytic agents and the blowing agent or agents. In addition, there may be other constituents in the formulation of both A and B components.

Common Component Properties

Example 1

An example of a rigid polyurethane foam formulation incorporating the combination of TDCE and HFE-7200 is:

Component A

Diphenylamine diisocyanate 39%

MDI Mixed Isomers 8% P-MDI 53%

Component B

TDCE 20%

HFE-7200 2% Urethane pre -polymers 78%

Mixed in equal proportions, with the further addition of a suitable catalyst and the optional addition of water, the components react to produce a rigid polyurethane foam of volume 20-40 times the initial mixed volume.

Example 2

An example of a rigid polyurethane foam formulation incorporating combination of TDCE and HFE-7200 is:

Component A

Diphenylamine diisocyanate 39% MDI Mixed Isomers 8% P-MDI 53%

Component B

TDCE 19%

HFE-7200 1%

Urethane pre -polymers 78%

Example 3

Component B

TDCE 20% HFE-7200 3% Butane 2%

Urethane pre -polymers

The use of TDCE in the B component has the effect of lowering the viscosity of the composition, thus enhancing its mixing characteristics. In the finished product, the use of TDCE as part of the blowing agent mixture is expected to enhance the fire performance of the finished product, despite itself being flammable.

Example 4 Component B

TDCE 20%

HFE-7200 3%

Urethane pre -polymers 75%

Example 5

Component A

Polymeric methane diphenyl diisocyanate (MDI) 100% Component B

Polyester polyol 71.3% Fire retardant 6.8%

Surfactant 1.4%

Blowing Agent 19.5% trans 1,2-dichloroethylene

1.0% 1-ethoxy nonafluorobutane Catalyst: Amine catalyst 0.5% of combined A+B side weights

The A and B side components are combined in a 1:1 ratio with stirring, catalyst is added and stirring continued for a further 30 seconds.

Cream Time: 38 seconds Gel time: 175 seconds

Tack free: 250 seconds After 24 hours: Free rise density 32.5 kg/m

Mean compressive Strength 147 kPa

Thermal Conductivity 0.0223 W/mK

Example 6

Component A

Polymeric methane diphenyl diisocyanate (MDI) 100%

Component B

Polyester polyol 71.3%

Fire retardant 6.8%

Surfactant 1.4% Blowing Agent 5.0% water

14.7% trans 1,2-dichloroethylene

0.8% 1-ethoxy nonafluorobutane Catalyst: Amine catalyst 0.5% of combined A+B side weights The A and B side components are combined in a 1:1 ratio with stirring, catalyst is added and stirring continued for a further 30 seconds.

Cream Time: 35 seconds

Gel time: 160 seconds Tack free: 235 seconds

After 24 hours:

Free rise density 35.6 kg/m Mean compressive Strength 134 kPa

Thermal Conductivity 0.0241 W/mK

Therefore mixtures of TDCE and HFE-7200 with the optional inclusion of a low boiling non-halogenated compounds such as the CI - C5 hydrocarbons or other compounds such as dimethyl ether and carbon dioxide provide for little flammability, a minimal flash point and minimal global warming potential compared to conventional industry solvents, in particular for use as a foaming agent. Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.

Claims

THE CLAIMS DEFINING THE INVENTION ARE:

1. A composition for use as a foaming or blowing agent comprising a mixture of 1,2-dichloroethylene and a fluorinated ether, said ether capable of lowering the flash point of 1,2-dichloroethylene and present in a flash point lowering amount.

2. A composition according to Claim 1 wherein the 1,2-dichloroethylene is trans- 1,2-dichloroethylene and the fluorinated ether is capable of minimising the flash point of trans- 1,2-dichloroethylene and is present in a flash point minimising amount.

3. A composition according to Claim 1 wherein the fluorinated ether is a flash point eliminating ether and is present in a flash point eliminating amount.

4. A composition according to any one of the preceding claims wherein the flash point is lowered such that it is not measurable.

5. A composition according to any one of the preceding claims wherein the amount of fluorinated ether is at least 1%.

6. A composition according to any one of the preceding claims wherein the amount of fluorinated ether is at least 5%.

7. A composition according to any one of the preceding claims wherein the amount of fluorinated ether does not exceed 20%.

8. A composition according to any one of claims 5 to 7 wherein the fluorinated ether is present in an amount of about 3% to about 6%.

9. A composition according to any one of the preceding claims wherein the fluorinated ether is an alkoxy substituted perfluoro compound.

10. A composition according to claim 9 wherein the alkoxy substituted perfluoro compound is l-ethoxy-nonafluorobutane.

11. A composition according to any one of the preceding claims wherein the fhiorinated ether comprises 1-ethoxy-nonafluorobutane and one or more additional fhiorinated ethers such that the amount of the one or more additional fhiorinated ethers is not more that 50% of the total amount of fhiorinated ether in the composition.

12. A composition according to claim 11 wherein the amount of the one or more additional fhiorinated ethers is not more that 30% of the total amount of fhiorinated ether in the composition.

13. A composition according to claim 11 or claim 12 wherein the amount of the one or more additional fhiorinated ethers is not more that 10% of the total amount of fhiorinated ether in the composition.

14. A composition according to any one of claims 11 to 13 wherein the additional fhiorinated ether is 1-methoxy-nonafluorobutane.

15. A composition for use as a foaming or blowing agent comprising a mixture of 1,2-dichloroethylene and an alkoxy substituted perfluoro compound, said perfluoro compound capable of lowering the flash point of 1,2-dichloroethylene.

16. A composition according to claim 15 wherein the 1,2-dichloroethylene is trans- 1,2-dichloroethylene and the alkoxy substituted perfluoro compound is capable of minimising the flash point of trans 1,2-dichloroethylene and is present in a flash point minimising amount.

17. A composition according to claim 15 or claim 16 wherein the alkoxy substituted perfluoro compound is a flash point eliminating compound and is present in a flash point eliminating amount.

18. A composition according to any one of the claims 15 to 17 wherein the amount of alkoxy substituted perfluoro compound in the composition is at least 1%.

19. A composition according to any one of the claims 15 to 18 wherein the amount of alkoxy substituted perfluoro compound in the composition is at least 5%.

20. A composition according to any one of the claims 15 to 19 wherein the amount of alkoxy substituted perfluoro compound in the composition does not exceed 20%.

21. A composition according to any one of claims 15 to 20 wherein the alkoxy substituted perfluoro compound is present in an amount of about 3% to about 6%.

22. A composition according to any one of claims 15 to 21 wherein the 1,2- dichloroethylene is trans- 1,2-dichloroethylene and the alkoxy substituted perfluoro compound is l-ethoxy-nonafluorobutane.

23. A composition according to any one of the claims 15 to 22 wherein the alkoxy substituted perfluoro compound comprises l-ethoxy-nonafluorobutane and one or more additional alkoxy substituted perfluoro compounds such that the amount of the one or more additional alkoxy substituted perfluoro compounds is not more that 50% of the total amount of the alkoxy substituted perfluoro compound in the composition.

24. A composition according to claim 23 wherein the amount of the one or more additional alkoxy substituted perfluoro compounds is not more that 30% of the total amount of fluorinated ether in the composition.

25. A composition according to claim 23 or claim 24 wherein the amount of the one or more additional alkoxy substituted perfluoro compounds is not more that 10% of the total amount of fluorinated ether in the composition.

26. A composition according to any one of claims 23 to 25 wherein the additional alkoxy substituted perfluoro compound is l-methoxy-nonafluorobutane.

27. A composition for use as a foaming or blowing agent comprising a mixture of trans- 1,2-dichloroethylene and a fluorinated ether that is l-ethoxy-nonafluorobutane, said l-ethoxy-nonafluorobutane being capable of minimising the flash point of 1,2- dichloroethylene .

28. A composition according to claim 27 wherein the 1-ethoxy-nonafhiorobutane is capable of minimising the flash point of trans 1,2-dichloroethylene and is present in a flash point minimising amount.

29. A composition according to claim 27 or claim 28 wherein the 1-ethoxy- nonafluorobutane is a flash point eliminating compound and is present in a flash point eliminating amount.

30. A composition according to any one of the claims 27 to 29 wherein the amount of 1-ethoxy-nonafluorobutane is at least 1%.

31. A composition according to any one of the claims 27 to 30 wherein the amount of 1-ethoxy-nonafluorobutane is at least 5%.

32. A composition according to any one of the claims 27 to 31 wherein the amount of 1-ethoxy-nonafluorobutane does not exceed 20%.

33. A composition according to any one of claims 27 to 32 wherein the 1-ethoxy- nonafluorobutane is present in an amount of about 3% to about 6%.

34. A composition according to according to any one of claims 27 to 33 comprising one or more additional fluorinated ethers such that the amount of the one or more additional fluorinated ethers is not more that 50% of the total amount of fluorinated ether in the composition.

35. A composition according to claim 34 wherein the amount of the one or more additional fluorinated ethers is not more that 30% of the total amount of fluorinated ether in the composition.

36. A composition according to claim 34 or claim 35 wherein the amount of the one or more additional fluorinated ethers is not more that 10% of the total amount of fluorinated ether in the composition.

37. A composition according to any one of claims 34 to 36 wherein the additional fhiorinated ether is 1-methoxy-nonafluorobutane.

38. A composition according to any one of the preceding claims having improved compressive strength.

39. A composition for use as a foaming or blowing agent comprising a mixture of 1,2-dichloroethylene and a f iorinated ether, said ether capable of lowering the flash point of 1,2-dichloroethylene and present in a flash point lowering amount and wherein a polymeric foam prepared from said forming or blowing agent has an improved compressive strength.

40. A composition according to claim 39 wherein the 1,2-dichloroethylene is trans- 1,2-dichloroethylene and the fhiorinated ether is an alkoxy substituted perfluoro compound.

41. A composition according to claim 39 or claim 40 wherein the 1,2- dichloroethylene is trans- 1,2-dichloroethylene and the fhiorinated ether comprises 1- methoxy-nonafluorobutane or 1-ethoxy-nonafluorobutane or mixtures thereof, said 1- methoxy-nonafluorobutane or 1-ethoxy-nonafluorobutane or the mixture thereof capable of minimising the flash point of 1,2-dichloroethylene.

42. A composition according to any one of claims 39 to 41 wherein the fhiorinated ether is 1-ethoxy-nonafluorobutane and is present in an amount of about 1 % to about

20%.

43. A composition according to any one of claims 39 to 42 wherein the fhiorinated ether is 1-ethoxy-nonafluorobutane and is present in an amount of about 3 % to about 6%.

44. A composition for use as a foaming or blowing agent comprising a mixture of 1,2-dichloroethylene and an alkoxy substituted perfluoro compound, said perfluoro compound capable of lowering the flash point of 1,2-dichloroethylene and wherein a polymeric foam prepared from said forming or blowing agent has an improved compressive strength.

45. A composition according to Claim 44 wherein the 1,2-dichloroethylene is trans- 1,2-dichloroethylene and the alkoxy substituted perfluoro compound is 1-methoxy- nonafluorobutane or l-ethoxy-nonafluorobutane or mixtures thereof.

46. A composition for preparing a polymeric foam comprising a mixture of 1,2- dichloroethylene and a fluorinated ether, said ether capable of lowering the flash point of 1 ,2-dichloroethylene.

47. A composition according to claim 46 wherein the 1,2-dichloroethylene is trans- 1,2-dichloroethylene and the fluorinated ether is l-ethoxy-nonafluorobutane.

48. A composition according to claim 46 or claim 47 wherein the polymeric foam is a polyurethane foam that is a rigid closed cell foam.

49. Use of a composition according to any one of the claims 1 to 48 in the preparation of a foam.

50. A method of preparing a foam wherein the composition of any one of claims 1 to 48 is the foaming or blowing agent.

51. A process of preparing a polymeric foam comprising reacting a compound according to any one of the claims 1 to 48 with one or more polymers or one or more compounds capable of forming a polymer to form a foam or cellular structure.

52. Polymeric foam obtained by the process of claim 51.

53. Use of a foaming or blowing agent comprising a mixture of 1,2-dichloroethylene and a fluorinated ether, said ether capable of lowering the flash point of 1,2- dichloroethylene and present in a flash point lowering amount in the preparation of a foam.

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54. Use according to claim 53 wherein the 1,2-dichloroethylene is trans- 1,2- dichloroethylene and the fluorinated ether is a alkoxy substituted perfluoro compound.

55. Use according to claim 53 or claim 54 wherein the 1,2-dichloroethylene is transit) 1,2-dichloroethylene and the fluorinated ether is 1-methoxy-nonafluorobutane or 1- ethoxy-nonafluorobutane or their mixtures thereof.

56. Use according to any one of claims 53 to 55 wherein the foam has improved compressive strength.

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57. A process of preparing a polymeric foam comprising reacting a foamable composition comprising a mixture of 1,2-dichloroethylene and a fluorinated ether, said ether capable of lowering the flash point of 1,2-dichloroethylene with one or more polymers or one or more compounds capable of forming a polymer to form a foam or 0 cellular structure.

58. A process according to claim 57 wherein the foam is a rigid closed cell foam.

59. A process according to claim 57 or claim 58 including the steps of preparing 5 polyurethane or polyisocyanurate foams by combining an isocyanate, a polyol or mixture of polyols, the composition of any one of claims 1 to 23, and other materials as required including catalysts, surfactants, colourants and the like.

60. A process according to any one of claims 57 to 59 wherein the 1,2- 30 dichloroethylene is trans- 1,2-dichloroethylene and the fluorinated ether is an alkoxy substituted perfluoro compound.

61. A process according to any one of claims 57 to 60 wherein the 1,2- dichloroethylene is trans- 1,2-dichloroethylene and the fluorinated ether is 1-ethoxy- nonafluorobutane .

62. A process according to any one of claims 57 to 61 wherein the fluorinated ether comprises 1-ethoxy-nonafluorobutane and one or more additional fluorinated ethers such that the amount of the one or more additional fluorinated ethers is not more that 50% of the total amount of fluorinated ether in the composition.

63. A process according to claim 62 wherein the one or more additional fluorinated ethers is not more that 30% of the total amount of fluorinated ether in the composition.

64. A process according to claim 63 wherein the one or more additional fluorinated ethers is not more that 10% of the total amount of fluorinated ether in the composition.

65. A process according to any one of claims 57 to 64 wherein the additional fluorinated ether is 1-methoxy-nonafluorobutane.

66. A blown or polymeric foam prepared from a composition according to any one of claims 1 to 48.

67. A blown or polymeric foam according to claim 66 wherein the polyurethane foam is a rigid closed cell foam and is prepared by the process of Claim 58.

68. A blown or polymeric foam according to claim 67 including small amounts of a composition according to any one of claims 1 to 48 contained within the cells.

69. A composition for use as a foaming or blowing agent; A composition for preparing a polymeric foam; Use of a foaming or blowing agent comprising a mixture of 1,2- dichloroethylene and a fluorinated ether; A process of preparing a polymeric foam; A blown or polymeric foam substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings and/or examples.