GB2568865A

GB2568865A - Composite absorbent materials and devices incorporating such materials

Info

Publication number: GB2568865A
Application number: GB1716917.8A
Authority: GB
Inventors: Ibbotson Colin
Original assignee: Manvers Engineering Ltd
Current assignee: Manvers Engineering Ltd
Priority date: 2017-10-15
Filing date: 2017-10-15
Publication date: 2019-06-05
Also published as: WO2019081248A1; GB201716917D0

Abstract

The composite hydrocarbon retaining material comprises at least one hydrocarbon absorbing and/or reactive material 3 secured between layers of porous material 2, 2’, which are mechanically bonded (4, figure 1) to each other through the oil absorbing and/or reactive material layer. The porous material 2,2’ is preferably oleophilic and hydrophobic non-woven. Preferred central layer 3 comprises oil super-absorbing polymeric particles or fibres. The mechanical bonding is preferably by hydro-entanglement, stich bonding or especially needle punching. The preferred composite also includes outer layers 410, 420 of porous hydrophilic material. Collectors having perimeter walls 430, mats, liners for collectors, bund walls and conduits containing the composite are used for dealing with leaks and spills of engine oil, diesel fuel or hydraulic fluids from automotive machinery used in civil engineering or electrical transformers.

Description

[0001] This invention relates to oil absorbent materials and to devices incorporating such materials especially collecting devices for collecting chemical or hydrocarbon spills or leakages and in particular those spills that may occur in the presence of water to be separated from the chemical or hydrocarbon.

BACKGROUND ART [0002] Leakage or accidental spillage of fluids such as chemicals or oil from machinery, in particular portable or automotive machinery used in civil engineering projects, or static machinery such as electrical and other transformers or from stationary automotive vehicles can lead to pollution of the ground. For example, engine oil, diesel fuel oil and hydraulic fluids can leak from such equipment as a catastrophic leakage or low persistent leakage over relatively long periods of time and these leakages can cause serious environmental damage. There are increasingly stringent requirements for dealing with ground contamination which can be very costly for any contractor or company responsible for the leakage. In a similar fashion, chemicals may leak and be problematic.

[0003] Various approaches have been investigated to address these leakage problems and to protect the environment. One solution has been to provide various means to collect and or trap hydrocarbon leakage and this has typically taken the form of collector beneath the machinery to collect and retain any fluids escaping from the machinery or spilled near it. One such oil collector is described in GB2428032. This portable collector comprises an integrated mat having a self-supporting perimeter wall upstanding from an impermeable base layer. The mat and wall comprise a layer of oleophilic material. The material of the wall is water permeable and any water, such as rain water, falling on the mat escapes through the water permeable wall. Oily fluids are retained by the oleophilic material for later disposal or reuse. Such a device is designed to deal with a further problem in that a large quantity of leaking equipment is exposed to the elements especially rainfall and any oil collecting solution for low quantities of oil leakage must also allow passage of relatively and sometimes significantly larger quantities of water. This water will inevitably be contaminated with oil from the leaking machinery and so any device must be able to remove this oil contamination as the contaminated water passes through or from it. These oil collector devices may utilise an additional oil/hydrocarbon absorbent mat comprising oleophilic material placed on top of the integrated mat and providing additional oil/hydrocarbon absorption capacity.

[0004] Oil/hydrocarbon absorbent mats may be used independently of other containment devices as a simple absorbent mat. Such mats typically comprise a oleophilic felt or similar material, which retains the oil/hydrocarbon. In some embodiments these mats are multilayer in structure and may comprise additional layers offering other functionality or properties to the mat. For example, a web top layer may be present to offer some support to the mat structure and abrasion resistance to the top surface that may be in contact with plant or machinery. Similar layers may be present as a base layer for similar functions. A more recent development is the incorporation of a further oil/hydrocarbon interactive layer, usually a centrally located layer sandwiched between two oleophilic layers, which may react with oil/hydrocarbon on contact to form a rubber type of reaction product. Whilst other layers may retain oil/hydrocarbon through physical absorption or adsorption onto or into oleophilic mat materials the material in this reactive layer reacts irreversibly with the oil/hydrocarbon to typically form a rubber. These reactive materials are polymeric materials are and typically present in the form of a powder or particulate or similar form. Mats with these layers are typically manufactured by adhesively bonding the layers to each other and trapping the coarsely deposited reactive polymer between adjacent adhesively bonded layers. A commercial example of such a mat is called the Green Rhino® EnviroPad, which is manufactured and supplied by Capture Green Limited, The Old Stables, The Gattinetts, East Bergholt, CO7 6QT, United Kingdom. A further example of such a mat is called C.l. Agent® Agent-X as manufactured and sold by C.l. Agent Solutions® of 11760 Commonwealth Drive, Louisville, KY 40299, United States of America, this material is described as being made of two layers of a geotextile with C.l.Agent® Polymers embedded between the layers.

[0005] These mats are difficult to manufacture and are problematic during use. The reactive polymers on contact with oil will typically initially dissolve as the oil is in higher local concentration than the polymer in the layer. As the particles are in a roughly bonded layer this temporary liquid state enables liquid flow within the layer. This liquid flow often causes problems in effective utilisation of the reactive polymer. This is because in some instances once the rubberised form is reached this prevents remaining oil/hydrocarbon from easily and freely moving through the layer to react with other reactive polymer regions. In addition, these reactive polymer layers may expand when they react with oil/hydrocarbons and become rubberised; this results in distortion of the mat and when localised regions or rubberised regions are present can result in an un-even mat structure during use. A further problem is that as the reactive polymer layer typically comprises a weakly bonded region of particles these structures are prone to delamination during with the resultant loss of reactive polymer powder and its contamination of surrounding areas, which is an environmental hazard.

[0006] There is a continuing need for alternative and/or more effective solutions for oil/hydrocarbon absorbing and/or adsorbing materials in general and in particular those that utilise oil/hydrocarbon reactive materials.

DISCLOSURE OF THE INVENTION [0007] The present invention is directed to a hydrocarbon absorbent and or adsorbent layered materials typically in the form of a mat and in addition to devices that utilize one or more of these layered materials to assist in the retention of spilt oil/hydrocarbon and/or the separation of spilt oil/hydrocarbon from water.

[0008] The present invention provides in a first aspect a composite hydrocarbon/oil retaining material comprising at least three layers wherein at least one layer comprises hydrocarbon absorbing and/or reactive material and wherein this layer of material is secured within the composite between two layers of porous material mechanically bonded to each other through the hydrocarbon absorbing and/or reactive material layer.

[0009] The mechanical bonding between these adjacent layers may be achieved through use of one er more of the following mechanical bonding techniques; needle punching, stitch bonding or hydroentanglement. It is preferred that the adjacent layers are mechanically bonded to each other via needle punching. Mechanical bonding is distinct from adhesive bonding, which is preferably avoided for bonding the porous layers adjacent to the absorbing and/or reactive material layer to each other although these porous layers individually may comprise adhesively bonded material. Mechanical bonding requires the interlocking of material from and between the adjacent porous material layers and/or the use of a third material in the form of for example a thread or staple mechanically securing the adjacent porous layers to each other. It is preferred that the mechanical bonding is as a result of the interlocking of material from and between the adjacent porous layers. It is possible to use one or more of these mechanical bonding techniques in combination with flame lamination of the layers, however it is preferred that the composite of the present invention is manufactured without the use of flame lamination.

[0010] The adjacent layers may comprise woven and/or non-woven materials and preferably comprise non-woven materials. Preferably these layers are non-woven fibrous layers that are oleophilic and are hydrophobic and porous enough so that water with or without hydrocarbon contamination may pass therethrough. In one embodiment the bottom layer may be mechanically bonded to or replaced by a hydrophilic layer and this layer may be a non-woven material. In this embodiment any water and hydrocarbon/oil mixture will first pass through the top layer and a proportion of the oil/hydrocarbon may be retained in the layer and separated from the water. The oil/hydrocarbon contaminated water remaining may then pass through to the middle reactive/ absorbent layer and remaining oil/hydrocarbon is removed from this mixture. Purified water is then able to pass from this layer with ease into and through the bottom layers and especially the hydrophilic layer, which whilst allowing water to pass therethrough repels the oil/hydrocarbon and forces this back into the oil reactive/absorbing layer. This stack of mechanically bonded multiple layers is able to therefore act as a graduated filter for the removal of oil/hydrocarbon from water. In an alternative embodiment the top layer may be mechanically bonded to or replaced by a hydrophilic layer and this layer may be a non-woven material.

[0011] The porous adjacent non-woven layer materials may be broadly defined as sheet or web structures bonded together by entangling fiber or filaments (and by perforating films) mechanically, thermally or chemically. They are flat or tufted porous sheets that are made directly from separate fibers, molten plastic or plastic film. They are not made by weaving or knitting and do not require converting the fibers to yarn.

[0012] These nonwovens are typically manufactured by putting small fibers together in the form of a sheet or web and then binding them either mechanically (as in the case of felt, by interlocking them with serrated needles such that the inter-fiber friction results in a stronger fabric), via adhesive, or thermally often with use of a binder material. Examples of suitable non-woven materials include staple nonwovens, melt-blown nonwovens, spun laid nonwovens, flash spun, spun jet, air-laid, wet-laid and other well-known forms. In many of these forms the laid fibre requires further treatment in the form of bonding of fibres to provide physical integrity to the nonwoven layer. Several bonding methods may be used and include be used: thermal bonding, hydro-entanglement, ultrasonic pattern bonding, needle punching/needle felting, chemical bonding with binders and melt blown, where fiber is bonded as air attenuated fibers intertangle with themselves during simultaneous fiber and web formation.

[0013] All nonwoven materials made by these techniques and which may be further processed to form a mechanical bond with an adjacent layer sandwiching a hydrocarbon absorbing and/or reactive material may be used in the present invention.

[0014] One suitable nonwoven is a polypropylene based felt material typically used in the manufacture of oil/hydrocarbon absorbing pads or matts and preferably is 4 denier polypropylene fiber in a nonwoven layer. Another suitable non-woven material is Geotextile-NW12, which is a polypropylene, staple fiber, needle-punched, nonwoven geotextile made with a proprietary additive. The fibers are needled to form a stable network that retains dimensional stability relative to each other. One preferred nonwoven material for one or more of the layers is a spun bond felt.

[0015] The hydrocarbon absorbing and/or reactive material layer may be a contiguous sheet of material as in a woven layer of material or may be a noncontiguous layer of material in the form of fibres and/or particulate materials. It is preferred that this layer comprises non-contiguous particulate and/or fibrous material and most preferably non-contiguous particulate material. This material being retained and secured between two layers of non-woven material that are mechanically interlocked with each other preferably through needle punching. The position of the particulate material is effectively fixed after needle punching and interlocking of the two adjacent non-woven layers and through this arrangement the particles and groups of particles are in fixed isolation from each other. Hydrocarbons/oil and water may pass through the non-woven layer and when the hydrocarbon/oil makes contact with the hydrocarbon absorbing and/or reactive material it is removed and isolated whilst ensuring that the reacted material remains in fixed isolation within the layer. This arrangement maintains the flow of liquid through the layer and ensures maximum effective utilization of the absorbing/reactive material.

[0016] If desired the composite material of the present invention may comprise multiple layers hydrocarbon absorbing and/or reactive material separated by non-woven layers that are mechanically bonded to each other. In addition, the hydrocarbon absorbing and/or reactive material of the present invention may be incorporated into other layered structures where the additional layers have other functions or properties e.g. wear resistance. The composite material of the present invention may be in the form of a replaceable matt or a fixed matt. In one embodiment the material of the present invention is in the form of a liner, which comprises a matt bottom and upstanding side-walls of the same material; such a liner may be used in combination with prior art collectors such as those described in GB2428032A.

[0017] The composite material of the present invention may be engineered into other structures used for the isolation of hydrocarbons/oils from spills and/or water and hydrocarbon/oil mixtures. Such structures include both temporary and fixed bund wall arrangements, filters, and such structures is described in GB2428032A.

[0018] The present invention further provides for a temporary or fixed bunds comprising the composite material of the present invention including also shut-off valve arrangements that may be incorporated into bund walls or other containment arrangements, where it is desired to allow hydrocarbon/oil contaminated water to be able to pass out of the containment through a conduit with the shut-off valve with removal of low levels of hydrocarbon/oil contamination and shut-off under hydrocarbon/oil deluge conditions.

[0019] Thus, the present invention further provides a containment device comprising at least one conduit from the interior to the exterior of the device and at least one layered containment pad comprising a composite material of the present invention spanning the conduit.

[0020] The containment pad may be secured within and span across the bore of the conduit and/or may be secured across the conduit opening; in both arrangements effectively sealing the conduit. In this embodiment the conduit is in communication between the interior and exterior of the containment device and the containment pad is arranged such that any and all liquids that pass from the interior of the device to the exterior through the conduit must also pass through the containment pad; it is a liquid flux barrier that allows liquids to pass therethrough but acts as a filter or shut-off valve by preventing small and large quantities of hydrocarbon from passing therethrough either in pure liquid form or as a mixture of hydrocarbon and water in which case the flux of water is only prevented when the hydrocarbon levels are high and the containment pad has completely closed off flux through the conduit. Thus, the containment pad is able to remove small quantities of hydrocarbons in water when their levels are low without preventing water flow through the conduit and is able to completely prevent the flow of water and hydrocarbon when the levels of hydrocarbon are high for example in a deluge condition.

[0021] The conduit may be an integral component of for example a wall of the containment device such as for example a bunding system. In this arrangement, the conduit is not designed to be removed or replaced and in one arrangement the containment pad is physically and permanently secured to or within the conduit. One arrangement is where the containment pad is a permanent part of a panel or series of panels in a bund wall arrangement.

[0022] Thus, the present invention further provides a bund wall system comprising a bund wall with at least one conduit for passive or active water removal from the interior of the bund and at least one containment pad located within the bore of the conduit and/or at one more of the openings of the conduit and configured to plug and shut off the conduit in the presence of organic hydrocarbon liquids.

[0023] In a preferred arrangement, the containment pad is part of a replaceable containment pad cartridge that may be reversibly secured to the containment device, for example within or to the conduits of the containment device. In this arrangement if the containment pad cartridge has been activated due to the passage of leaked material then it may be easily removed and replaced without the need for total replacement or re-building of the containment device. Thus, in this arrangement the containment device may be designed to accommodate replaceable containment pad cartridges. The containment device cartridges may take any form that may be secured to a conduit of a containment device. In one arrangement for added security of operation the conduit of the containment device may be designed to enable a containment pad cartridge to be secured within the bore of the conduit and/or at one or more of the external entrances to the bore of the conduit. In this arrangement containment pads, proximate to the interior of the containment device may be selectively replaced as and when they become contaminated with hydrocarbon and the interior or exterior containment pads have not been contaminated and are still fully functional.

[0024] The containment pad comprising a composite material of the present invention preferably comprises at least three layers. The top layer or layer facing the interior of the containment device comprises porous layer material. The middle layer comprises swellable polymeric material which imbibes and/or reacts with hydrocarbon organic liquids such as oils and especially preferred imbibes and/or reacts with synthetic oils and especially transformer or insulating oils. The bottom layer or layer facing the exterior of the containment device comprises porous layer material. These three layers are mechanically bonded together to provide a robust integral containment pad, which may also be referred to as a filter pad. The top and bottom layers may and preferably do comprise non-woven oleophilic materials such as for example felt based materials that may be used in oil recovery and clean-up. Preferably the top and bottom layers are manufactured from 4 denier polypropylene fiber in a nonwoven layer. All three layers may be of similar thickness and preferably the middle layer or core of the containment pad comprising swellable polymeric material is thinner than the top and bottom layers. This is an important arrangement of layers as it has been found that ensuring a rapid and effective valve like shut-off is achieved using this layer arrangement alone or in combination with other layers of materials within the containment device. This relatively thin pad is beneficial in ensuring reasonable flux of water through the valve from, for example, the containment area of a bund wall system, whilst providing rapid and effective reaction to hydrocarbon contact and quick and effective shut-off performance to ensure no or minimal amounts of hydrocarbon pass from the containment device.

[0025] In a preferred embodiment one or both of the top and bottom layers are hydrophobic.

[0026] Transformer oil or insulating oil is an oil that is stable at high temperatures and has excellent electrical insulating properties. It is used in oilfilled transformers, some types of high-voltage capacitors, fluorescent lamp ballasts, and some types of high-voltage switches and circuit breakers. Its functions are to insulate, suppress corona and arcing, and to serve as a coolant. Transformer oil's primary functions are to insulate and cool a transformer. It must therefore have high dielectric strength, thermal conductivity, and chemical stability, and must keep these properties when held at high temperatures for extended periods. Typical specifications are: flash point 140 °C or greater, pour point -30 °C or lower, dielectric breakdown voltage 28 kV (RMS) or greater. Transformer oils include: mineral oil; pentaerythritol tetra fatty acid natural and synthetic esters, especially those with a fire point of over 300 °C; silicone oils and fluorocarbon-based oils. In a preferred embodiment of the present invention the middle reactive layer of the containment pad comprises swellable polymeric material which imbibes and/or reacts with transformer or insulating oils.

[0027] The containment pad may provide all of the shut-off function of the containment device or, with the use of less responsive swellable polymeric materials within the pad, may act as a rapid flow attenuator, under for example deluge conditions, to slow down the flow of hydrocarbon or hydrocarbon containing material from the interior of the containment device e.g. though the conduit so that the lower levels/flow of hydrocarbon passing through it may then be more easily and fully absorbed or imbibed by a second containment pad and/or other hydrocarbon absorbing and retaining arrangement downstream of the first or primary containment pad, and thus forming a possibly larger more robust plug for the valve like shut-off effect within the conduit. With prior art devices where thicker layers have been used significant levels of hydrocarbon oil escape through the valve before a full shut-off plug is formed. In the present invention, the thin layer has the advantage of rapid shut-off and or attenuation of flow, which in combination with further containment pads and/or plug forming arrangements ensures effective hydrocarbon retention within the containment device and significantly reduced risk of contamination.

[0028] With reference to the middle layer any hydrocarbon swellable and/or hydrocarbon reactive polymeric material which imbibes and/or reacts with hydrocarbon organic liquids may be used. The polymer should imbibe and/or react with hydrocarbons under deluge conditions in order to form a hydrocarbon impenetrable plug of material by any suitable mechanism.

[0029] Although having no mechanical parts as such the containment pad is acting as a shut-off or safety valve. One preferred application is in bunding containment devices, where a conduit containing the containment pad allows rainwater or other sources of water that have accumulated within the bund wall to pass out, preferably, passively to the exterior of the bund wall without compromising the integrity of the bund wall. The conduit may also we associated with a pump arrangement that pumps water through the conduit from the interior of the bunding device; such an arrangement may be advantageous when a large quantity of water has accumulated within the bund wall and needs to be removed quickly to return the bunding containment to its maximum operating capacity. In most situations, passive flow without pumping is acceptable and it is possible to operate both passive and pumped arrangements with the containment pads of the present invention.

[0030] A collector for machine fluids, comprising a mat having a perimeter wall upstanding therefrom, the mat and/or the wall comprising oleophilic material and the wall being water-permeable, whereby water falling into the collector can escape therefrom, while oily fluids are retained by said oleophilic material and wherein the collector comprises at least one composite according to the present invention.

[0031] Preferably the oleophilic material of the wall comprises a porous foam material and most preferably a reticulated foam material and preferably in the form of a cylinder. The oleophilic material of the wall may comprise fibres of an oily plastics material, more preferably isopolyolefin, and most preferably wherein the polyolefin is polypropylene. Preferably the foam and/or fibres are contained within a permeable fabric cover and preferably the fabric is a woven or nonwoven fabric formed from a plastics material and preferably the plastic material is polypropylene. Typically and preferably there is a nonwoven felt layer between the oleophilic foam/fibre core and the fabric. Preferably, this felt layer is between 1-10 mm in thickness, most preferably 2 to 8 mm in thickness and most preferably 2 to 4 mm in thickness and most preferably comprises nonwoven felt material of density from 100 to 400 g/m², more preferably 150 to 300 g/m², more preferably 200 to 300 g/m², and most preferably 225 to 300 g/m². The matt preferably comprises an impermeable base layer. It is preferred that the collector is arranged such that all of the hydrocarbon/oil containing water passes through a composite material of the present invention located within and/or at the surface of the self-supporting perimeter wall. Preferably the perimeter wall is self-supporting. In a preferred embodiment a composite layered material of the present invention is located between the felt layer and the core foam/fibre region. In a further embodiment a composite layered material of the present invention is bonded to the interior inward facing surface of the felt layer. In an alternative embodiment a composite layered material of the present invention may incorporate a felt layer as one or more of its layers.

[0032] The collector of the present invention when incorporating sufficient composite materials of the present invention, preferably as multiple layers, may have a dual function. Under normal conditions when there virtually oil free water enters the collector this water will pass from the collector through its walls and the composite materials of the present invention and out of the collector; there are no changes to the composition of the collector walls. When there are low levels of oil contamination in any water collected as this oily water passes through the upstanding walls the low levels of oil may initially be absorbed onto the oleophilic fibre layers in the wall either as additional filling in the wall or as part of the composite materials of the present invention located within the wall structure; any oil that is not absorbed will make contact with and react with the reactive material in the composite materials of the present invention. Thus, there are two possibilities for oil removal from any oily water passing through the upstanding sidewall. If the wall is constructed to have a region of oleophilic fibre material located at its inner surfaces facing into the interior of the collector and a region of composite materials of the present invention at the peripheral section of the upstanding wall facing towards the exterior of the collector then the initial contact area for oil water will be the oleophilic fibre filling and virtually all of the low levels of oil will be removed by this region before it reaches the composite materials contacting region; minor levels of oil will be retained in this region. With this arrangement the composite materials region is a last resort section of the wall for removing oil and will not become ineffective over time due to persistent low levels of oil removal. However, if and when there is a catastrophic leakage of hydrocarbon/oil into the collector the peripheral composite region will be able to react rapidly with the large quantity of hydrocarbon/oil and form an impenetrable barrier to the escape of hydrocarbon/oil from the collector. Thus, the dual action is to provide removal of persistent low levels of hydrocarbon/oil contamination from water passing through the collector and to provide an emergency bund wall function in the case of catastrophic leakage and deluge conditions. The presence of multiple layers of the reactive polymer in the multiple composite materials of the present invention provides an effective emergency bund wall by rapidly shutting of the escape route for hydrocarbons/oil from the collector.

[0033] The hydrocarbon absorbing and/or reactive material layer may comprise any material or combination of materials that either absorb or react with hydrocarbons/oil to immobilize the hydrocarbon/oil and when present as a contaminant to remove the hydrocarbon/oil from a solvent or liquid such as water. Reaction is used in the broadest sense and includes materials that may dissolve in hydrocarbons/oils and in doing so cause the hydrocarbon/oil to solidify and become immobilized. Suitable materials are described below.

[0034] One suitable material is the commercially available material Green Rhino CG1 Polymer, supplied by Capture Green Limited, The Old Stables, The Gattinetts, East Bergholt, CO7 6QT, United Kingdom. This material is a blend of polymers that is specifically blended to capture and retain hydrocarbons such as oil, diesel, petrol, hydraulic fluid, transformer liquid and more. The polymers are capable of completely solidifying the hydrocarbon until it becomes a solid mass that will not leak - this offers an effective method for managing and removing unwanted waste oils from the environment. The polymers in the form of a white granular powder work by having a physical attraction with hydrocarbons. On contact with the hydrocarbon the viscosity increases creating a solid rubber like substance that will not leak, even under applied pressure. Once the polymers are activated by contact with hydrocarbon, the oil is locked in permanently and cannot be released.

[0035] A further suitable material is the commercially available material called C.I.Agent polymer as manufactured and sold by C.l. Agent Solutions® of 11760 Commonwealth Drive, Louisville, KY 40299, United States of America, [0036] A further suitable material is the commercially available material called Petroguard-D as supplied by Guardian Environmental Technologies, Connecticut, USA. This material takes the form of a dry white granular high capacity instant solidifying absorbent. This reacts with hydrocarbons/oil to form a solid. This material is typically provided commercially as granular particles of 20 to 60 mesh (approximately 0.84 to 0.25 mm). It is preferred that in all embodiments and aspects of the present invention that this material and other materials for this feature of the invention are ground so as to have a particle size that is less than 0.25 mm, preferably less than 0.20 mm and most preferably less than 1.5 mm. This reduced particle size provides better performance within the composites of the present invention.

[0037] A further suitable material is the commercially available material is called Deurex PURE as supplied by DEUREX AG, Dr.-Bergius-St^e 8-12 06729 Elsteraue, Germany. This material is described as a hydrophobic wax cotton which has a high surface area and strongly adsorbs hydrocarbons/oils. It is a fibrous material.

[0038] Generally, there are at least three different types of oil-solidifying substances, including polymer sorbents, cross-linking agents, and polymers with cross-linking agents. Polymer sorbents, sometimes called super-sorbents, adsorb oil into spaces between polymers, and oil is held in these spaces by van der Waals forces, which are weak attraction forces between molecules. Examples of polymers that are capable of being solidifiers include, block copolymers such as styrene butadiene and related polymers, poly-tertiary-butylstyrene, polyacrylo-nitrile butadiene, polyisoprene (rubber), polyethylene and polypropylene, poly isobutylene and related polymers.

[0039] Cross-linking agents are chemical products that form chemical bonds between two hydrocarbons to solidify the oil. The reaction is that of a chemical one and typically can release a small amount of heat or absorb that amount of heat depending on the chemical used. Examples of cross-linking agents include norbornene, anhydrides, and a series of oil treating agents created by Pelletier and Siron (1999) (Environmental Technology and Chemistry, May 1999, Vol. 18, Issue 5, Pages 811-1075), that are prepared by reacting surfactants, alcohols or carboxylic acids with alkychlorosilanes in light hydrocarbon solvents.

[0040] Polymers with cross-linking agents also form chemical bonds. These types of solidifiers combine a polymeric sorbent with a cross-linking agent, and the purpose of this combination is to gain the advantages of both polymers and cross-linking agents. An example of this type of solidifier includes a product called RigidOil by British Petroleum. The agent consists of two liquids which are generally mixed shortly before applying to the oil. The one liquid consists of a 10% maleinized polybutadiene of molecular weight 8000 with 50% of odorless kerosene plus ester, as a diluent. The other liquid consists of a cross-linking agent, zinversate diethanolamine also in 50% kerosene/ester (9:1).

[0041] A general description of polymer-based oil-solidifying substances may be found in the Environmental Protection Agency's (EPA's) National Response Team (NRT) and Regional Response Team (RRT) factsheet entitled “Application of Sorbents and Solidifiers for Oil Spills” (February 2007), and a description of the three above-mentioned oil-solidifying substances may be found in Fingas, “A Review of Literature Related to Oil Spill Solidifiers 19902008” (September 2008), the teachings of both of which are incorporated herein by reference in their entirety.

[0042] In a further embodiment, the specific hydrocarbon/oil reactive polymers useful in the practice of the present invention are any polymers which are water insoluble and which swell and/or solidify on contact with organic liquids. Useful polymers may also swell on contact with water. However, additional swelling must occur when contacted with an organic liquid. Selection of a polymer for use with any organic liquid is readily accomplished by determining a swelling index for the polymer particles. Beneficially, such a swelling index is readily determined by immersing a particulate polymer to be evaluated in water until the polymer has reached equilibrium swelling and subsequently adding the desired organic liquid and determining the volume per unit weight of polymer after a period of 30 minutes with water and organic liquid and the volume per unit weight of the polymer when in equilibrium with water. The ratio of the volume per unit weight with organic liquid and water to volume per unit weight of the polymer with water provides the swelling index. If the polymer is soluble the swelling index is infinite. If the swelling index is greater than about 1.2 the polymer particles are useful in the practice of the present invention. Beneficially for most applications a swelling index of at least 1.5 and preferably greater than about 3 is desirable. It is not critical to the practice of the present invention to employ a cross-linked polymer which swells but does not dissolve. If the polymer swells in the presence of the organic liquid with or without water it is suitable for the practice of the present invention. However, it is desirable to employ a polymer which is cross-linked to a sufficient degree that it exhibits a swelling index between about 1.5 and 50 and preferably between about 3 and 50. By utilizing the cross-linked polymer the hazard of dissolution of the polymer over extended periods of time is eliminated.

[0043] Thus, in the present invention a wide variety of polymeric materials are employed with benefit in the swellable layer. Such polymers include polymers of styrenes and substituted styrenes; copolymers of vinyl chloride such as a copolymer of 60 weight percent vinyl chloride and 40 weight percent vinyl acetate; vinylidene chloride copolymers such as a copolymer of 75 percent vinylidene chloride and 25 percent acrylonitrile; acryllic polymers such as polymers of methylmethacrylate, ethyl acrylate and the like. In general, the chemical composition of the polymers is not critical. The polymers preferably show significant swelling; that is, at least a 25 percent increase in volume in a period of at least 10 minutes in the organic liquid to which the polymers are required to respond under desired service conditions of temperature and pressure. Particularly advantageous materials which respond to a wide variety of organic liquids are polymers of styrene such as polystyrene and polymers of styrene and divinylbenzene containing up to about 10 weight percent divinylbenzene. For general use with aliphatic and aromatic hydrocarbons, alkylstyrene polymers are of particular benefit. Such alkylstyrene polymers swell very rapidly on contact with aliphatic and/or aromatic hydrocarbons. Generally, the more rapid the swelling of the polymer the more rapid the shutoff when the organic hydrocarbon liquid is contacted. Alkylstyrene polymers usually show substantial swelling when in contact with organic hydrocarbon liquids in less than 1 minute.

[0044] Preferably, cross-linked polymers of styrenes, and advantageously of tertiary-alkylstyrenes, are utilized as the imbibing agent in the middle layer of the containment pad of this invention. Those alkylstyrenes which can be used to prepare these polymers have alkyl groups containing from four to 20, and preferably from four to 12, carbon atoms, such as: tertiary-alkylstyrenes including for example, p-tert-butylstyrene, p-tert-amylstyrene, p-tert-hexylstyrene, p-tert-octylstyrene, p-tert-dodecylstyrene, p-tert-octadecylstyrene, and p-tert-eiscosylstyrene; n-alkylstyrenes including for example n-butylstyrene, namylstyrene, n-hexylstyrene, n-octylstyrene, n-dodecyl-styrene, noctadecylstyrene, and n-eicosylstyrene; sec-alkystyrenes including for example sec-butylstyrene, sec-hexylstyrene sec-octylstyrene, sec-dodecylstyrene, secoctadecylstyrene, and sec-eicosylstyrene; isoalkyl-styrenes including for example isobutylstyrene, iso-amylstyrene, isohexylstyrene, isooctylstyrene, isododecyl-styrene, isooctadecylstyrene, and isoeicosylstyrene; and copolymers thereof.

[0045] Especially preferred for use in the practice of this embodiment of the invention are cross-linked copolymers of such alkylstyrenes as heretofore described and an alkyl ester derived from C1 to C18 alcohol and acrylic or methacrylic acid or mixture thereof.

[0046] Suitable monomers which may be employed as comonomers with the alkylstyrene include such materials as vinylnaphthalene, styrene, .alpha.methylstyrene, ring-substituted .alpha.-methylstyrenes, halostyrenes, arylstyrenes and alkarylstyrenes; methacrylic esters, acrylic esters, fumarate esters and half esters, maleate esters and half esters, itaconate esters and half esters, vinyl biphenyls, vinyl esters of aliphatic carboxylic acid esters, alkyl vinyl ethers, alkyl vinyl ketones, .alpha.-olefins, isoolefins, butadiene, isoprene, dimethylbutadiene, acrybnitrile, methacrylonitrile and the like.

[0047] It is desirable that the polymers used in the swellable layer of the containment pad of the invention contain a slight amount of cross-linking agent, preferably in the range of from about 0.01 to 2 percent by weight. The most efficient imbibition of organic liquid contaminants occurs when the level of cross-linking agent is less than about 1 percent since this permits the polymers to swell easily and imbibe a substantial volume of the organic hydrocarbon material.

[0048] Cross-linking agents which can be used in preparing the imbibing polymers suitable for use in the present invention include polyethylenically unsaturated compounds such as divinylbenzene, diethylene glycol dimethacrylate, diisopropenylbenzene, diisopropenyldiphenyl, diallylmaleate, diallylphthalate, allylacrylates, allylmethacrylates, allylfumarates, allylitaconates, alkyd resin types, butadiene or isoprene polymers, cyclooctadiene, methylene norbornylenes, divinyl phthalates, vinyl isopropenylbenzene, divinyl biphenyl, as well as any other di- or poly-functional compound known to be of use as a cross-linking agent in polymerica vinyladdition compositions. Normally, the polymer containing the cross-linking agent swells with the imbibed organic hydrocarbon material. If there is too much cross-linking agent, the imbibition takes an unreasonably long time or the polymer is unable to imbibe a sufficient quantity of the organic. If the imbibitional polymer contains no cross-linking agent or too little cross-linking agent, then it will dissolve eventually in the organic material resulting, for example, in a non-discrete, non-particulate mass of polymer-thickened organic liquid. However, for many applications where closure of a line is quickly noticeable uncross-linked material is satisfactory.

[0049] Swellable polymers for use in the present invention may be prepared by any convenient technique, either suspension, emulsion or mass polymerization. Generally, the method of preparation is selected to provide polymer in the most convenient form for any particular application. Thus, suspension polymerization is employed to provide a plurality of small beads. If it is desired to obtain a maximum amount of polymer surface and a relatively high permeability rate toward water carrying an organic liquid, it is oftentimes desirable to employ an emulsion polymerization technique and recover the polymer by spray drying. If it is desired to obtain a body of predetermined configuration, it is oftentimes beneficial to employ a mass polymerization technique wherein a polymer-insoluble diluent is employed. Techniques for the preparation of such porous polymers are disclosed in U.S. Pat. No. 3,322,695, the teachings of which are herewith incorporated by reference. Such porous polymers can also be prepared by either suspension or mass polymerization. Alternately, satisfactory layers may be prepared by mass or suspension polymerization with subsequent comminution of the polymer prepared by the mass technique. The particle size of such polymers is selected in accordance with the desired application. For most applications, such particles are from about 0.1 to 5 millimeters in diameter. Alternately, porous polymer layers may be polymerized in desired shapes in the manner of U.S. Pat. No. 3,322,695.

[0050] Further preferred examples of suitable swellable polymers that may absorb and imbibe organic hydrocarbons are as described in Hall et al., U. S . patent No. 3, 750, 688, which on contact with the organic hydrocarbon substance, swell as it is absorbed or imbibed. A coating on a particulate material such as described in Larson et al., U. S. patent 4, 302, 337, may be employed. It may not be critical to employ a cross-linked polymer that swells but does not dissolve. However, cross-linked organic hydrocarbon liquidimbibing polymers are preferred. Suitable polymers include polymers of styrenes and substituted styrenes; copolymers of vinyl chloride including a copolymer of vinyl chloride and comonomers such as vinyl acetate, vinylidene chloride, acrylonitrile, methacrylonitrile, acrylates, methacrylates and acrylic polymers such as polymers of methylmethacrylate, ethyl acrylate. Particularly advantageous materials which respond to a wide variety of organic hydrocarbon liquids are the polymers of styrene such as polystyrene and copolymers of styrene and divinylbenzene containing up to ten weight percent divinylbenzene. For general use with aliphatic and aromatic hydrocarbons, and halogenated hydrocarbons, alkylstyrene polymers and copolymers are of particular benefit. Alkylstyrene polymers usually show substantial swelling in less than a minute when in contact with organic hydrocarbon liquids. Crosslinked polymers of styrenes, notably tertiary-alkylstyrenes, are used to advantage as the imbibing polymer. Those alkylstyrenes which can be used to prepare these imbibing polymers have alkyl groups having one to twenty, especially four to twelve, carbon atoms, examples of which include methylstyrene; ethylstyrene; dimethylstyrene; p-tert-butyl, m-tert-butyl, secbutyl, and/or iso-alkyl styrenes such as of butylstyrene; amlystyrene; hexylstyrene; octylstyrene to include 2-ethyl-hexylstyrene, iso-octylstyrene and di-t-butylstyrene; dodecylstyrene; octadecylstyrene; and eiscosylstyrene. Further, cross-linked copolymers of such alkylstyrenes as aforementioned and an alkyl ester derived from a one to twenty-four carbon alcohol and acrylic or methacrylic acid or mixture thereof. Suitable monomers which can be employed as comonomers with the alkylstyrene include such materials as vinylnaphthalene, styrene, alpha-methylstyrene, methylstyrene , methylstyrene, ring-substituted alpha-methylstyrenes , halostyrenes, arylstyrenes and alkarylstyrenes , methacrylic esters , acrylic esters , and cyclohexyl and isobornyl esters of acrylic and methacrylic acids ; esters and half esters of fumaric, maleic , itaconic acids ; vinyl biphenyls , alkyl vinyl ethers , alkyl vinyl ketones , alpha-olefins , iso-olefins , butadiene, isoprene, dimethylbutadiene , acrylonitrile, and methacrylonitrile. As previously described a slight amount of cross-linking agent can be contained in the polymer, say, in the range about from 0.01 to two percent by weight. A highly efficient imbibition of organic hydrocarbon liquid contaminants occurs when the level of cross-linking agent is less than about one percent by weight since this permits the polymers to swell easily and imbibe a substantial volume of the organic hydrocarbon material. Suitable cross-linking agents include polyethylenically unsaturated compounds such as divinylbenzene, diethylene glycol dimethacrylate, diisopropenylbenzene, diisopropenyldiphenyl, diallylmaleate, diallylphthalate, allylacrylates , allymethacrylates , allylfumarates , allylitaconates, alkyd resin type cross-linking agents , polybutadiene or polyisoprene polymers , cyclooctadiene, methylene norbornylenes , divinyl phthalates , vinyl isopropenylbenzene , divinyl biphenyl, as well as any other di- or polyfunctional compounds known to be of use as a cross-linking agent in polymeric vinyl addition polymer compositions . If there is too much cross-linking agent, the imbibition takes an unreasonably long time, or the polymer is unable to imbibe a sufficient quantity of the organic liquid, and interstitial spaces in the swellable layer are not completely closed when contacted with organic hydrocarbon. If the imbibitional polymer contains none or too little cross-linking agent, then it may well eventually dissolve or partially dissolve to a loose gel in the organic material resulting, for example, in a non-discrete, non-particulate mass of polymer-thickened organic liquid. However, for the present invention uncrosslinked material may be satisfactory under the minimal ambient pressure conditions associated with a containment device. Preferably, the swellable layer of the present invention comprises as absorbent IMBIBER BEADS® type of particles, which are made of lightly crosslinked alkylstyrene copolymers, and thus are hydrophobic and oleophilic in general, and appear to the naked eye as a powder, having a particle size distribution of about from forty to four hundred microns, for example, as available from Imbibitive Technologies Corp, USA.

[0051] Preferred swellable and/or reactive polymers for the middle layer of the containment pad are commercially available as Petroguard-D (Guardian Environmental technologies, USA), Imbiber Beads® (Imbibitive Technologies Corporation, USA), ZEP-O-ZORB (Zep Inc, Atlanta USA) and C.l. Agent polymer (C.I.Agent Solutions, Kentucky, USA). Materials such as PetroguardD, are highly preferred as they react with hydrocarbons to form a rubber like product; these are high capacity super absorbent polymers that instantly absorbs and solidifies oil and other hydrocarbons. These materials provide a highly effective plug in the containment pad of the present invention. In a preferred embodiment, the swellable polymer is in the form of a beads in the containment pad middle layer and are immobilized within a permeable matrix of preferably polymer material. In this arrangement, the particles are able to absorb and swell in contact with hydrocarbon materials but do not coalesce together in a localized plug but remain dispersed across the containment pad and ensure that the whole pad volume is filed with individually swollen absorbing and reacting polymer particles. Such a matrix also aids in the handling of the particulate polymer materials and the manufacture of the containment pad and device. This matrix material, whilst supporting the polymeric particles is of a form and density that it does not significantly inhibit the swelling of the particles and formation of the shut-off plug within the containment pad.

[0052] The preferred method of manufacture of the composite material of the present invention is to distribute powder form hydrocarbon/oil reactive/absorbant polymer at the desired level of loading as a layer onto a web of a desired fibrous non-woven material and to locate a second web of the nonwoven on top of the powder form hydrocarbon/oil reactive/absorbant polymer layer. This loose multilayered composite is then introduced into a needle punching machine at the desired settings to needle punch the two nonwoven layers together trapping and securing the powder form material between them.

[0053] It should be understood that all and any aspects and embodiments as described herein may be combined in any number of combinations.

[0054] FIG. 1 shows a sectional view of a composite material according to the present invention, [0055] FIG. 2 shows a sectional view of a containment pad according to the present invention located within a conduit;

[0056] FIG. 3 shows a sectional view of a bund wall conduit with externally located containment pad cartridge according to the invention, [0057] FIG.4 and 4 (a) shows a perspective and sectional view of a hydrocarbon/oil retaining matt incorporating a composite material according to the present invention;

[0058] FIG. 5 shows a perspective view of a collector for machine fluids according to the present invention, [0059] FIG. 6 shows a sectional view along the line A-A of FIG.5 of an embodiment of the collector with a composite material associated with the mat of the collector;

[0060] FIG. 7 shows a sectional view along the line A-A of FIG.5 of an embodiment of the collector with a composite material associated with the upstanding sidewalls of the collector; and [0061] FIG. 8 shows a sectional view along the line A-A of FIG.5 of further embodiments of the collector of the present invention with alternative arrangements for use of a composite material associated with the upstanding sidewalls of the collector.

DETAILED DESCRIPTION [0062] With reference to Figure 1, there is shown a composite material (1) comprising three layers (2, 2’ and 3). The top and bottom layers (2,2’) are made of oil absorbing nonwoven felt layers which are typically a nonwoven material such as a nonwoven polypropylene felt or similar. Sandwiched between these layers (2, 2’) is a further layer (3) of oil absorbing and/or reactive polymeric material. In this example this layer (3) is a layer of discreet particulate material. This middle layer (3) allows water to pass therethrough but absorbs and prevents the passage of hydrocarbons and oils, which are absorbed by or react with the particulate oil absorbing and/or reactive polymeric material. Also shown is the needle punched mechanical connections (4) between the top and bottom layers (2, 2’). These connections (4) consists of fibers from both layers (2, 2’) that have become interlocked and form a mechanical bond through the action of needle punching processing of the three layers. It can be seen that the particulate material present in layer (3) is effectively trapped between these mechanical connections (4). This robust and simple arrangement ensures that the composite material has a high level of integrity and stability and that the particulate material is securely retained in the desired location for use of the layered material.

[0063] With reference to Figure 2, there is shown a containment device (10) comprising a conduit (20), having a bore (30) and located within the bore (30) of the conduit (20) is a containment pad (40) which comprises a composite material (1) as illustrated in Figure 1. The conduit may be made of metal or plastic material. During use and prior to any failure of equipment or primary containment within the bund any water (x) located within the bunded area passes from the bund and into the conduit (20) and passes through the containment pad (40) and exits the conduit (20) at Y. Any small amounts of oil or hydrocarbon may be retained in the middle layer (3) as shown on Figure 1 of the pad (40) and at low levels do not cause this layer to significantly expand or swell and to shut-off the flow of water through the conduit from the interior of the bund. The top and bottom layers (2, 2’) are mechanically bonded to each other via needle punched mechanical connections (not shown). Upon failure of the containment vessel or equipment within the bund large quantities of oil or hydrocarbon will pass from the bund at X and enter the conduit (20). This hydrocarbon liquid makes contact with the containment pad (40) and quickly causes the middle layer (3) to gel or solidify to form an impenetrable plug layer thus preventing any further passage of oil or hydrocarbon into and through the conduit. At the same time, no further water may exit the bund through the conduit. Once the containment failure has been addressed and the bund is back to normal operation the containment pad may be replaced with a new containment pad. The device of Figure 2, may be modified to include two or more containment pads arranged in series in contact with each other within the bore of the conduit or they may be located within the bore and separated from each other. In this arrangement, any small quantities of hydrocarbon that get through the containment pad in first contact with released hydrocarbons will be absorbed and withheld by subsequent containment pads downstream of the first pad. In addition, should the first containment pad fail to fully operate subsequent pads may act as a fail-safe.

[0064] The arrangement of the present invention will be providing a suitable flux for water through the containment pads (40) is such that the flux of hydrocarbon or oil is reduced and this enables the effective formation of a robust shut-off plug within the valve before any oil or hydrocarbon exist the conduit (20). Thus, with the present invention there is no need for any additional processes further downstream of the device (10) to ensure contamination levels in the water are low and the water exiting the device (10) may pass straight to sewage or drainage systems.

[0065] In a preferred embodiment, the containment pad (40) is heat sealed or adhered to the internal surface of the conduit (20). The containment pad (40) may be secured within a suitable housing, which is sealed to or adhered to the conduit surface.

[0066] In the present invention, the sandwich of three layers in the containment pad (40) with mechanical interlocking of layers ensures that the thin hydrocarbon gellable layer (3) remains intact and forms a thin localized plug in the conduit (20). This is particularly useful when the polymer dissolves within the hydrocarbon to gel it.

[0067] The polymer within the containment pad sandwich is preferably selected to be reactive with and too transformer and/or other synthetic oils.

[0068] In a preferred embodiment, the containment pad (40) is in the form of a cartridge wherein the containment pad is secured within a suitable housing that may be screwed or otherwise secured to a conduit of a containment device, such as a conduit that passes through a bund wall. In this form, the containment pad cartridge is easily replaced to ensure rapid and regular maintenance of the bund and when there has been a shut-off event associated with the bund. The conduit and the cartridge housing may be adapted to allow such a cartridge to be secured within the bore of the conduit of the bund wall. In another arrangement and in addition the conduit may be arranged such that a containment pad (40) cartridge may be secured to both the inlet and outlet of the conduit. Generally, a containment pad cartridge will comprise a housing for retaining the components of a containment pad secured within the housing e.g. by being heat sealed or adhesively secured to the housing material.

Alternatively, the containment pad components bay be bonded to each other to form a free-standing containment pad that may be easily handled as a unit and may then be secured within an appropriate housing using for example a clamping and sealing arrangement or a two-component screw cartridge; in this arrangement only the containment pad need be replaced when maintenance is required and the cartridge housing may be re-used. The cartridge housing is adapted to be either permanently or reversibly secured within or to a conduit in for example a bund wall containment device. The profile of the housing may be the same as the conduit i.e. circular in cross-section albeit of smaller diameter for easy and tight fitting within the bore of the conduit. Alternatively, the conduit and the housing of the cartridge may be adapted to be securely screwed to each other; this may be allow interior placement of the cartridge within the bore of the cartridge or bay securing the cartridge to the inlet and/or exit of the conduit.

[0069] Referring to Figure 3, the containment device (110) as a bund wall secured into the ground has a conduit (120) passing through the wall (130) of the containment device (110). Located and secured within the bore (150) of the conduit (120) is a containment pad cartridge (140) comprising a layered hydrocarbon/oil retaining material (1) as illustrated in Figure 1. The cartridge (140) may be secured in place by means of a screw thread arrangement between cartridge and conduit with use of a suitable stop or clamp retaining means or the like.

[0070] Referring to Figure 4, an oil absorbing mat (400) is generally rectangular in shape, but can be any desirable shape. The mat (400) is of a multilayer construction as shown in Figure 4(a) in which a composite material (1) of the present invention. This is as illustrated in Figure 1, and having a core layer of hydrocarbon absorbing and/or reactive material (3) and top and bottom layers (2, 2’) of nonwoven material mechanically bonded layers. This constructions is further sandwiched between two further top and bottom layers (410, 420). The top layer (410) may be made of a wear resistant fabric or open mesh material that may be hydrophobic or may allow oily water to pass therethrough so that it is able to contact the core layered hydrocarbon/oil retaining material. The bottom (420) may be made of the same material or may be made from a non-porous, impermeable and robust polymeric sheet material. All of these layers form the mat (400) and are bound at their edges with a polymeric or fabric edging material (430). There may be other layers present in the mat (400) if desired that offer the same or different function to the layers illustrated.

[0071] Referring to Figure 5, the collector shown (500) has a rectangular mat (501) having an upstanding wall (502) around its perimeter. The side wall structure (502) is manufactured such that it has sufficient rigidity to be selfsupporting during use but that it may also be compressed upon the application of pressure as in for example when a vehicle or piece of equipment transverses the wall for location upon the mat for operation or use. The self-supporting side wall after compression and removal of compressive forces is able to decompress to its original or approximately original shape. The combination of the mat (501) and the upstanding wall (502) provides for a containment area for a vehicle or piece of machinery and to act as a collector of oil/hydrocarbon that may escape from the vehicle or machinery and any water that falls upon and runs off the vehicle or machinery e.g. rainfall during its external use.

[0072] Referring to Figure 6, the collector shown (600) has an upstanding wall (602) that may be formed as a tubular fabric structure (603) filled with conventional hydrocarbon/oil adsorbing material (604); in one embodiment it is filled in whole or in part with polypropylene fibre material. This wall (602) is secured to a mat (601), which has a composite material (605) of the present invention secured to an impermeable base layer (606). During use oil/waterfall into the containment area (607) and make contact with the mat (601), the majority of the water will flow from the mat (601) and out of the containment area via the side walls (602); any oil/hydrocarbon mixed with this water will be removed by the conventional oleophilic absorbing material (604) within the sidewalls (602). This mixture will also make contact with the mat (601) and in the first instance the composite material of the present invention (605). As it does most of the oil present is absorbed by the top layer (608) of this layered material (605) and residual oily water is then able to pass into the middle layer (609) of hydrocarbon absorbing and/or reactive material, which removes the residual oil and relatively pure water is then able to pass into the bottom layer (610) but is not able to exit the collector (600) through the impermeable base layer (606) of the mat (601) and is forced to exit the mat via the exposed edges (611) of the matt and or the side wall (602). In typical use the machine or vehicle will release oil/hydrocarbon in the absence of water and this leakage will be absorbed into and retained through immobilization in the top layered region (605) of the mat (601). If there is then any precipitation in the form of for example rain and this contacts the collector because the oil/hydrocarbon is immobilized in region (605) it is not washed out of the collector (600) but is retained. Low levels of rainfall may not actually exit the collector (600) via the side walls but may exit the (collector) through the mat (601) at its periphery (611). Under heavier rainfall e.g. under deluge rainfall conditions water may exit via the sidewalls (602). With this arrangement water is unable to accumulate within the collector (600) and oil/hydrocardon leaked into the collector (600) is able to be efficiently removed. This collector (600) may be used with a removable liner that may be used as the primary oil/hydrocarbon absorbing layer and the other components of the collector (600) are used for secondary oil/hydrocarbon removal after oil/hydrocarbon with or without water has saturated the primary oil/hydrocarbon recovery layer with oil/hydrocarbon. The liner may comprise a layered material according to the invention or may be any suitable conventional liner as described in the art for oil spill retention. Examples of liners for use in the present invention include: Plant Nappy® refills as manufactured and supplied by Manvers Engineering Ltd, Unit 7 Spring Hill Road, Park Springs, Barnsley, South Yorkshire, England; SpillTrapper pads as supplied by Fentex Ltd, Station Road, Warbouys, Cambs, PE28 2TH: or Enviropad® as manufactured and supplied by Green Rhino Ltd, The Old Stables, The Gattinetts, East Bergholt, CO7 6QT, United Kingdom. The present invention is therefore in a further embodiment directed to a collector as herein described in combination with a liner pad.

[0073] Referring to Figure 7, the collector (700) has an upstanding wall (702) that may be formed as a tubular structure (703) filled with conventional hydrocarbon/oil adsorbing material (704); in one embodiment it is filled in whole or in part with polypropylene fibre material. This wall (702) is secured to a mat (701), which has a layer of oil absorbing material (705) of similar composition to that filing the sidewalls (704) secured to an impermeable base layer (706). The exterior of the tubular wall structure (703) is made of a water and oil permeable fabric and located within this fabric layer adjacent to its interior surface is a layer of the composite material of the present invention (707). During use oil will typically fall into the containment area (708) and make contact with the mat (701) and be absorbed into the oil absorbing material layer (705). During rainfall water will wash any residual oil/hydrocarbon from any machinery or vehicle located within the containment area (708) and this will make contact with the mat (701); on contact the majority of the oil will be removed from the water and absorbed into the layer (705) of the mat. And oily water will also pass from the mat surface and out of the containment area through the sidewalls (702). This mixture of oil and water on entering the sidewall will make contact with the composite material of the present invention (707) present in the sidewall (702). As it does so most of the oil present in the mixture will be absorbed by the outer layer (709) of this layered material (707) and residual oily water is then able to pass into the middle layer (710) of hydrocarbon absorbing and/or reactive material, which removes the residual oil by reaction and/or absorption and relatively pure water is then able to pass into the inner layer (711) and then into the bulk of the side wall material (704), which is able to remove any oil/hydrocarbon of present by simple absorption. As the water passes through the wall (702) towards the exterior of the collector (700) it will traverse the exterior wall surface and a further region of composite material of the present invention (707). Thus the oily water as it passes through the sidewall (702) will be exposed to multiple regions of oil absorbing and or reacting material either as conventional material (704) or two regions containing the composite material of the present invention (707). Under deluge conditions water will pass through the sidewalls (702). If there is a catastrophic failure of the machine or vehicle resulting in a large leakage of oil/hydrocarbon then the composite material of the present invention (707) in the first region will be completely reacted with the oil and will effectively seal this region to further escape of oil/hydrocarbon but if any does escape it will be caught by and react with the second region of composite material of the present invention (707). This sidewall (702) is compressible but due to the robust nature of the composite material of the present invention (707) through incorporation of mechanical bonding this structure remains substantially intact during continued use. This robust nature allows this embodiment to provide effective bunding functionality in the event of a catastrophic leak from the machine or vehicle within the collector. Thus this collector allows for steady removal of collected water during use, the continuous removal of low levels of oil contamination during use and an effective bunding function for major leakages. The impermeable bottom layer (706) also ensures that the oil/hydrocarbon is retained within the collector (700).

[0074] Referring to Figure 8, two sidewall arrangements are illustrated. The collector (800) has an upstanding wall (802) that may be formed as a tubular structure (803) filled with conventional hydrocarbon/oil adsorbing material (804); in one embodiment it is filled in whole or in part with polypropylene fibre material. This wall (802) is secured to a mat (801), which has a layer of oil absorbing material (805) of similar composition to that filing the sidewalls (804) secured to an impermeable base layer (806). The exterior of the tubular wall structure (803) is made of a water and oil permeable fabric.

[0075] In one embodiment located at the internal surface of this fabric layer at the exterior region of the side wall (802) is a section of the composite material of the present invention (807). During use oil will typically fall into the containment area (808) and make contact with the mat (801) and be absorbed into the oil absorbing material layer (805). During rainfall water will wash any residual oil/hydrocarbon from any machinery or vehicle located within the containment area (808) and this will make contact with the mat (801); on contact the majority of the oil will be removed from the water and absorbed into the layer (805) of the mat. And oily water will also pass from the mat surface and out of the containment area through the sidewalls (802). This mixture of oil and water on entering the sidewall (802) will make contact with conventional hydrocarbon/oil adsorbing material (804) and on doing so the majority of the residual oil will be removed from the mixture. The water then traverses through the wall material (804) and contacts the composite material of the present invention (807) present in the sidewall (802). As it does so most of the oil still present in the mixture will be absorbed by the inner layer (809) of this layered material (807) and residual oily water is then able to pass into the middle layer (810) of hydrocarbon absorbing and/or reactive material, which removes the residual oil by reaction and/or absorption and relatively pure water is then able to pass into the outer layer (811) and then exist the collector (800). The layer (807) is illustrated as a continuous mechanically bonded layer that is located within the whole interior surface of the sidewall (802), but the reactive layer (809) is only present in one region towards the exterior the other region (812) does not have a middle layer but comprises two mechanically bonded later of nonwoven material.

[0076] The second embodiment in Figure 8, has a multilayered block (813) of the composite material of the present invention (807), which is embedded within the conventional hydrocarbon/oil adsorbing material (804) within the sidewall (802). The block (813) in this example has three layers (807) bonded to each other. In this arrangement as oily water leaves the containment area (808) and passes through the sidewall (802) it must pass through conventional hydrocarbon/oil adsorbing material (804) then three regions of oil reactive/absorbent material (810) each mechanically encapsulated within two nonwoven layers ( 809, 811) and then through a further region of conventional hydrocarbon/oil adsorbing material (804) before exiting the collector (800). This embodiment provides the same functions as the first embodiment of Figure 8 but has three regions of oil reactive/absorbent material (810) and thus provides a more robust bunding function.

[0077] In all of the collector embodiments sidewalls may be continuous, or may be constructed in sections joined together at the comers, again according to the desired plan shape of the collector. The collector may have any desirable shape. The sidewall may be formed from a fabric tube stuffed with polypropylene fibres and provided with a flattened base for attachment to the mat around the periphery thereof. The impermeable base may be plastic such as for example, of the type of plastics sheeting used as groundsheets and for temporary shelters and the like. The fabric tube may be a water- and oilpermeable plastics woven or nonwoven textile material, for example of the type used in making overalls.

[0078] The sidewalls may be attached to the mat by stitching, by adhesive, for example a hot-melt adhesive, or by welding, for example using radiofrequency welding. Similar methods may be employed to secure the different layers of the mat together.

[0079] It is understood that any embodiment described herein may be used in combination with one or more of each of the other embodiments and all of these combination of embodiments are within the scope of the present invention.

[0080] All of the features disclosed in this specification for each and every embodiment (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Claims

1. A composite hydrocarbon/oil retaining material comprising at least three layers wherein at least one layer comprises hydrocarbon absorbing and/or reactive material and wherein this layer of material is secured within the composite between two layers of porous material mechanically bonded to each other through the hydrocarbon absorbing and/or reactive material layer.

2. A composite according to claim 1, wherein the hydrocarbon absorbing and/or reactive material comprises one or more oil super absorbing polymers.

3. A composite according to claim 1, wherein the hydrocarbon absorbing and/or reactive material comprises one or more polymers in particulate form.

4. A composite according to claim 1, wherein the hydrocarbon absorbing and/or reactive material comprises one or more polymers in the form of fibres.

5. A composite according to claim 1, wherein the hydrocarbon absorbing and/or reactive material comprises C J. Agent polymer as manufactured and sold by C.l. Agent Solutions® of 11760 Commonwealth Drive, Louisville, KY 40299, United States of America.

6. A composite according to claim 1, wherein the hydrocarbon absorbing and/or reactive material comprises Petrogruard-D as supplied by Guardian Environmental Technologies, Connecticut, USA.

7. A composite according to claim 1, wherein the hydrocarbon absorbing and/or reactive material comprises Green Rhino CG1 Polymer, supplied by Capture Green Limited, The Old Stables, The Gattinetts, East Bergholt, CO7 6QT, United Kingdom.

8. A composite according to claim 1, wherein the hydrocarbon absorbing and/or reactive material comprises Deurex PURE as supplied by DEUREX AG, Dr.-Bergius-Stra8e 8-1206729 Elsteraue, Germany.

9. A composite according to claim 1, wherein the hydrocarbon absorbing and/or reactive material comprises a hydrophobic wax cotton which has a high surface area and strongly adsorbs hydrocarbons/oils.

10. A composite according to claim 1, wherein the layers of porous material are woven and/or non-woven materials.

11. A composite according to claim 1, wherein the layers of porous material are both non-woven materials.

12. A composite according to claim 1, wherein the layers of porous material are oleophilic and are hydrophobic.

13. A composite according to claim 1, wherein at least one of the layers of porous material is hydrophilic.

14. A composite according to claim 1, wherein the bottom layer of porous material is hydrophilic.

15. A composite according to claim 1, wherein a further layer of hydrophilic porous material is bonded to the bottom layer of porous material.

16. A composite according to claim 15, wherein the further layer of hydrophilic porous material is mechanically bonded to the bottom layer of porous material.

17. A composite according to claim 1, comprising multiple layers of hydrocarbon absorbing and/or reactive material.

18. A composite according to claim 1, wherein the mechanical bonding between layers is achieved through use of one or more of the following mechanical bonding techniques; needle punching, stitch bonding or hydroentanglement.

19. A composite according to claim 1, wherein the mechanical bonding between layers is achieved through use of needle punching.

20. An oil/hydrocarbon containment device comprising at least one conduit from the interior to the exterior of the device and at least one layered containment pad comprising one or more composites according to claim 1, spanning the conduit.

21. A collector for machine fluids, comprising a mat having a perimeter wall upstanding therefrom, the mat and/or the wall comprising oleophilic material and the wall being water-permeable, whereby water falling into the collector can escape therefrom, while oily fluids are retained by said oleophilic material and wherein the collector comprises at least one composite according to claim 1.

22. A oil retaining mat comprising one or more composites according to claim 1.

23. A liner for a collector comprising one or more composites according to claim 1.

24. A collector according to claim 21 further comprising a liner.

25. A collector according to claim 21 further comprising a liner incorporating a composite according to claim 1.

26. A collector according to claim 21 further incorporating a Plant Nappy® refills as manufactured and supplied by Manvers Engineering Ltd, Unit 7 Spring Hill Road, Park Springs, Barnsley, South Yorkshire, England.

27. A collector according to claim 21 further incorporating a SpillTrapper pad liner as supplied by Fentex Ltd, Station Road, Warbouys, Cambs, PE28 2TH.

28. A collector according to claim 21 further incorporating an Enviropad® liner as manufactured and supplied by Green Rhino Ltd, The Old Stables, The Gattinetts, East Bergholt CO7 6QT, United Kingdom.

29. A collector according to any one of claims 26 to 28, wherein the refill or liner comprises one or more composites according to claim 1.