OIL-ABSORBENT MATERIALS

Field of the Invention

The present invention relates to oil-absorbent materials, and in particular to products that are capable of selectively absorbing oil over aqueous liquids.

Background to the Invention

Oil spillages can be large-scale ecological disasters or smaller scale incidents at home or in the workplace. The removal of oil often requires the use of sorbents. Frequently, the sorbents used are formed from oil derived polypropylene (PP) meshes.

An alternative approach described in the art is that whole feathers can be used to remove oil and oil-like products from a liquid.

Feathers are made up of many slender, closely arranged parallel barbs forming a vane on either side of a tapering hollow shaft (the quill). The barbs have bare barbules (extensions from the barbs) which in turn bear barbicels commonly ending in hooked hamuli and interlocking with the barbules of an adjacent barb to link the barbs into a continuous vane. The vanes provide the feather barb material (the feather fibre). A typical poultry feather fibre length is about 2 to 3 cm.

Feathers are an abundant by-product of the poultry and down industry. Feather waste consists of insoluble fibre, soluble protein, fat and water. Feathers contain about 90% keratin protein. Feather keratin is composed of ordered a-helix or P-sheet structures and some other disordered structures. Feather barb material has a higher percentage of a-helix compared to P-sheet, while the quill is composed of more P-sheet than a-helix structure.

The following disclosures relate to using whole feathers to provide a feather-based oil-absorbent material or product:

US4759847A discloses a filter, including a flexible mesh having whole feathers secured thereto, for separating out oil from an oily liquid.

US9598293B2 discloses an oil-absorbent boom structure having an inner core that includes an oil-absorbent material which is a combination of whole feathers and bi-component fibres of polypropylene/polyethylene. US2014367323A1 discloses an oil-absorbent felt comprising whole feathers. This felt material is formed by a process involving thermal fusion of whole feathers and bi-component fibres of polypropylene/polyethylene.

WO2012055264A1 discloses an oil absorption cloth made from whole feathers and polypropylene/polyethylene bi-component fibres sprayed with a water-based adhesive.

DE10140909A1 discloses a feather pillow for use as an oil trap. The pillow comprises loose whole animal feathers surrounded on all sides by an oil-permeable cover.

The following disclosures also relate to using feathers:

WO2011/082603 uses waste feathers from which the feather shaft (quill) is removed to form an oil-absorbing cloth or fillers. The feather-based cloth/filler is deployed in a hydrophobic composite material to form a composite structure that can be used to absorb oil and waterinsoluble organic liquids.

CN101385921A uses feather fibres and bi-component fibre to form a non-woven feather fabric, which is compounded with a layer of non-woven unbound fabric to obtain a non-woven filtering composite material. The feather fibres are directly removed from chicken, duck, goose, peacock, or ostrich poultry feather feathers, without any special treatment. The non-woven material is described as having good filtering performance, and being able to adsorb heavy metals, dyes, oil stains, organic solvents and other harmful substances.

JP2002105938 describes a natural down fibre oil adsorptive mat that is formed from 10mm chopped lengths of washed and dried feathers.

JPH10310962A uses a wet-laid paper-making process to obtain a paper-like non-woven substance from ground feather powder. The non-woven fabric is described as having oilabsorbing performances.

There remains a need for further oil-absorbent materials.

There remains a need for oil-absorbent materials that exhibit excellent oil absorption, and selectively absorb oil over water. There remains a need for oil-absorbent materials that have excellent capillary action for drawing oil into the material.

Summary of the Invention

The present inventors identified a number of problems associated with using whole feathers as oil-absorbent materials.

Firstly, whole feathers are brittle, and do not return to their original form once crushed. This limits the reusability of materials based on whole feathers.

Secondly, whole feather-based materials will include whole quills, and these can pierce any container into which they are placed. In addition, these whole quills prevent the formation of a homogenous material with a regular pore size. An irregular pore size places a limit on the amount of oil that the material can absorb and retain.

Thirdly, whole feathers can have a tendency to come loose from an oil-absorbent product, such as a boom structure, and to then potentially be irretrievable from the sea or ocean.

Although some products formed from parts of feathers are known, as noted above, the present inventors have identified a specific form of feathers that gives particularly effective results, and good control over properties.

The present inventors have identified that an improved oil-absorbent product can be obtained by forming a non-woven mat from a fibrillated fibre blend comprising both fibrillated feather barb material and fibrillated feather quills.

As the skilled person will appreciate, a fibrillated fibre blend comprising both fibrillated feather barb material and fibrillated feather quills involves a mixture of fibrillated feather barb material and fibrillated feather quills. The nature of a blend involves a mix of the different components. A whole feather would not be considered as a mixture of feather barb material and feather quills.

In the processed blend used in the invention, both barbs and quill are present; however, unlike in a whole feather, barbs are separated from the quill. Therefore in the blend used in the present invention there is fibrillated feather barb material that is physically separated from (not attached to), but mixed with, fibrillated feather quill material. Preferably most or all of the fibrillated feather barb material is physically separated from (not attached to) the fibrillated feather quill material. In addition, as the skilled person will also appreciate, a fibrillated fibre is one that has been processed to develop a branched structure. This is therefore a fibre product with fibrils extending off from the main fibre body in multiple different directions. A fibrillated fibre blend comprising both fibrillated feather barb material and fibrillated feather quills may, in particular, be obtained by the process described in W02017/221015A1, the content of which is incorporated herein by reference.

Therefore a fibre blend comprising both fibrillated feather barb material and fibrillated feather quills would not be obtained without specifically processing the feathers to develop a branched structure, with fibrils extending off from the main fibre body in multiple different directions.

The prior art noted above does not discuss fibrillation of feathers, and in particular does not disclose using a mixture of (i) feather barb material that is fibrillated and (ii) feather quill material that is both fibrillated and separated from (not attached to) the feather barb material.

It has, unexpectedly, been determined by the inventors that excellent oil absorption is achieved by providing feathers as fibrillated fibres (both fibrillated feather barb material and fibrillated feather quills) that are in the form of a non-woven mat. The nature of a fibrillated fibre is that it has a branched structure and thus a higher surface area. This specific combination of materials and structure results in there being small pores distributed throughout the mat. Without being bound by theory, it is believed that that the combination of these pores together with the oleophilic nature of the feather material leads to the unexpectedly good results, e.g. in terms of the high level of oil absorption.

In particular, not only does the mat based on feathers that have been processed to obtain fibrillated feather barb material and fibrillated feather quill material exhibit excellent oil absorption, but it also selectively absorbs oil over water. This makes the product ideal for use in containing and/or cleaning oil spills in an environmental, industrial or domestic context.

The invention provides, in a first aspect, a method for absorbing oil, the method comprising the steps of: a) providing a non-woven mat that comprises a fibrous web of fibrillated fibres comprising a mixture of both fibrillated feather barb material and fibrillated feather quills; b) bringing the non-woven mat into contact with a volume of oil; and c) allowing some or all of the volume of oil to be absorbed into the non-woven mat. The invention also provides, in a second aspect, the use of a non-woven mat to absorb oil, wherein the non-woven mat comprises a fibrous web of fibrillated fibres comprising both fibrillated feather barb material and fibrillated feather quills. The barbs are separated from (not attached to) the quill.

The non-woven mat out-performs polypropylene absorbents with respect to oil absorbency. The non-woven mat out-performs whole feathers with respect to oil-absorbency.

The non-woven mat can be re-used. It has been shown that the non-woven mat can be washed and dried and then used again to absorb oil.

The mat has a relatively homogeneous structure, and this means that fractures and tears are less likely to form over time than in less homogenous materials, such as products made from whole feathers.

This homogeneity also ensures that the non-woven mat has an improved aesthetic and user experience. This is particularly important if the material is formed into a wipe for domestic or industrial use.

The absence of whole feather quills also avoids damage being caused by sharp quills. In particular, this ensures that any container into which the non-woven mat is placed will not be pierced or otherwise damaged by sharp quills during use or storage.

The non-woven mat is formed from a waste product and can be re-used. Thus, it provides a “green” oil-absorbent product. In particular, the non-woven mat is more environmentally friendly than the polypropylene absorbents currently used to treat oil spills and whole feather materials described in the art. Furthermore, as will be appreciated further from the discussions below, by appropriate selection of the starting materials, e.g. binder, the non-woven mat can be both biodegradable and reusable. In one embodiment, the non-woven mat is biodegradable according to ASTM 5511 or ASTM 5338.

The non-woven mat remains buoyant in water, even when saturated with oil.

The non-woven mat has excellent capillary action for drawing oil into the material. Its density can be increased to increase this capillary effect. The non-woven mat is effective at selectively absorbing oil over water in a range of different water types, including tap water, river water and saltwater (e.g. seawater or brackish water).

The fibrillated fibre blend may comprise a main fibre body with a plurality of fibrils extending off that body at different locations along its length, and with those fibrils extending in multiple (e.g. three or more, or five or more, or ten or more) different directions. In particular, when considering the main fibre body as extending in the z direction, then when looking in the x-y plane there may be fibrils extending at multiple (e.g. three or more, or five or more, or ten or more) different angles in that plane, from 0 to 360 degrees. Equally, when considering the angle of the fibrils to the elongate axis of the main fibre body, there may be fibrils extending at multiple (e.g. three or more, or five or more, or ten or more) different angles to that axis, from greater than 0 to less than 180 degrees. These characteristics can be established by looking at a scanning electron microscopy (SEM) image of the fibre blend.

It is preferred that the non-woven mat is air-laid. In particular, this may result in excellent oilabsorbent properties for the mat.

Without being bound by theory, it is believed that improved oil-absorbency is achieved by using air-laying because it is possible to form larger pore sizes with this technique as compared to other non-woven techniques. In addition, air-laid nonwoven formation involves no aqueous steps; this minimises the possibility that the feather material is hydrated during processing into mat form. It is believed that hydration of the feather material during the mat formation may inhibit oil absorbance.

The skilled person will appreciate that a mat as made by air-laying is distinguishable from a mat made by other non-woven techniques such as wet-laid or needle punching. In particular, air-laid nonwoven textiles have a layered formation, and this layering can be visually observed in a sample of the mat.

It is also possible to produce air-laid non-woven mats that have a density gradient, i.e. the material is denser on the bottom than the top. The skilled person will appreciate that the density of a mat can be calculated as weight/volume, based on weighing the mat to obtain the weight and by measuring the dimensions and then calculating the volume from these dimensions. The mat can also be split into a top part and a bottom part, and the respective densities of these parts can be determined. The invention further provides, in a third aspect, a process for obtaining an oil-absorbent nonwoven mat, the process comprising the steps of:

A) providing a fibrillated fibre blend comprising a mixture of both fibrillated feather barb material and fibrillated feather quills;

B) depositing the fibrillated fibre blend to form a web of fibrillated fibres; and

C) carrying out a web consolidation step, to obtain a non-woven mat.

It is preferred that step (B) comprises air-laying the fibrillated fibre blend to form a web of fibrillated fibres.

In one preferred embodiment, the process further comprises the step of pressing the non-woven mat to achieve a desired thickness and/or a desired density.

It may be that the pressing step is carried out to achieve a density of 25 kg/m ³ or more, e.g. 40 kg/m ³ or more, preferably 50 kg/m ³ or more. In one embodiment, the pressing step is carried out to achieve a density of 60 kg/m ³ or more, preferably 70 kg/m ³ or more, or 80 kg/m ³ or more, e.g., 100 kg/m ³ or more, or 125 kg/m ³ or more, or 140 kg/m ³ or more, or 150 kg/m ³ or more, or even 200 kg/m ³ or more. It may be that the density is from 25 kg/m ³ to 500 kg/m ³ e.g. from 40 kg/m ³ to 450 kg/m ³ or from 50 kg/m ³ to 425 kg/m ³ or from 60 kg/m ³ to 400 kg/m ³ . It may be that the density is from 25 kg/m ³ to 300 kg/m ³ e.g. from 40 kg/m ³ to 250 kg/m ³ or from 50 kg/m ³ to 225 kg/m ³ or from 60 kg/m ³ to 150 kg/m ³ . Densities can be measured manually with a calliper, measuring tape and a microbalance.

In one embodiment, the pressing step is carried out to achieve a thickness of 50mm or less, such as 40mm or less; e.g. from 0.5mm to 50mm, or from 1mm to 40mm. A pillow or boom may, for example, have a useful thickness of about 30 to 40mm, and a wipe may, for example, have a useful thickness of about 1 to 3mm.

It may be that in one embodiment the pressing step is carried out to achieve a thickness of 8mm or less, such as 6mm or less, preferably 5mm or less, such as 4mm or less, or 3mm or less, or 2mm or less.

In one embodiment, the process further comprises the step of forming the non-woven mat into a shaped article, e.g. by moulding or cutting. The non-woven mat can be formed into a variety of shapes, suitable for a variety of purposes. For example, the non-woven mat could be formed into a wipe, cloth, towel or mophead, e.g., making it suitable for use as a surface cleaning wipe, or it could be formed into a roll or boom, e.g., for use in containing industrial oil spills, or it could be formed into a filter, e.g. for use in filtering oil out from a liquid.

The fibrillated fibre blend provided in step (A) may, in particular, be made by the process described in W02017/221015A1 using a hammer mill. A scanning electron microscopy (SEM) image will show that in the product formed by this process there is a main fibre body with a plurality of fibrils extending off that body at different locations along its length, and with those fibrils extending in multiple (e.g. three or more, or five or more, or ten or more) different directions. In particular, when considering the main fibre body as extending in the z direction, then when looking in the x-y plane there are fibrils extending at multiple (e.g. three or more, or five or more, or ten or more) different angles in that plane, from 0 to 360 degrees. Equally, when considering the angle of the fibrils to the elongate axis of the main fibre body, there are fibrils extending at multiple (e.g. three or more, or five or more, or ten or more) different angles to that axis, from greater than 0 to less than 180 degrees.

This fibrillated fibre blend can have primary, secondary and tertiary branches. It is believed that this results in an increased internal fibre surface area and an increased number of pores.

In one embodiment, step (A) involves making a fibrillated fibre blend by the process described in W02017/221015A1.

Therefore, in one embodiment of the third aspect, the process comprises the steps of:

(A-i) providing whole feathers in a non-chemically treated form;

(A-ii) washing the whole feathers as obtained from step (A-i) with an aqueous liquid at elevated temperature, to obtain whole washed feathers;

(A-iii) drying the whole washed feathers as obtained from step (A-ii) to obtain whole dried feathers;

(A-iv) milling the whole dried feathers as obtained from step (A-iii) with a hammer mill using a plurality of rotating hammers to force the feathers against a curved grinding surface having raised teeth, wherein the minimum clearance as a hammer tip passes over the grinding surface defines a grinding gap which is from 1mm to 6mm, and whereby the ground feather material is forced out of the mill through screen perforations by the action of the rotating hammers, whereby the screen perforations are substantially circular with a diameter of from 3mm to 10mm so as to obtain a fibrillated fibre blend comprising both fibrillated feather barb material and fibrillated feather quills;

(B) depositing the fibrillated fibre blend to form a web; and

(C) carrying out a web consolidation step, to obtain a non-woven mat. The use of the specific hammer mill process as defined in step (A-iv) gives rise to a fibrillated form of fibres obtained from a feather product. The hammer mill, in contrast to a cutting mill, introduces abrasive and targeted compressive forces. This has the effect of opening up the feather fibres to create a three-dimensional product as compared to a flat, 2D feather. It also generates crimping and maximises the contact surface area of the resulting fibre product.

The variable properties between individual feathers and between different sections within a feather result in the production of fibrillated feather fibres with heterogeneous physical properties. However, as a bulk material, the fibrillated fibre blend as obtained by the invention has an overall homogenous behaviour. The homogeneity also allows for further processing such as heat pressing and moulding.

In one embodiment, the non-woven mat as provided in step a) of the method of the first aspect is obtainable by the process of the third aspect.

In one embodiment, the non-woven mat as provided in step a) of the method of the first aspect has been obtained by the process of the third aspect.

In one embodiment, step a) of the method of the first aspect comprises carrying out the process of the third aspect.

The invention provides, in a fourth aspect, a non-woven mat obtainable by the process of the third aspect. The mat may be in the form of a shaped article.

In one embodiment, the non-woven mat has a density of 30 kg/m ³ or more, preferably 40 kg/m ³ or more, e.g., 50 kg/m ³ or more. In one embodiment, the non-woven mat has a density of 60 kg/m ³ or more, preferably 70 kg/m ³ or more, or 80 kg/m ³ or more, e.g., 100 kg/m ³ or more, 125 kg/m ³ or more, or 150 kg/m ³ or more, or even 200 kg/m ³ or more.

The invention provides, in a fifth aspect, an oil-absorbent product comprising the non-woven mat of the fourth embodiment.

In one embodiment, the oil-absorbent product is a wipe, cloth or mophead, or a roll or boom, or a filter. In one embodiment, the product of the fifth aspect further comprises a container within which the oil-absorbent material is located. It may be that the oil-absorbent material is enclosed within the container. The container may be formed from fabric. In some embodiments the fabric is made from a biodegradable material, for example, jute, cotton, wool, flax, hemp, rattan or combinations thereof.

In all aspects of the invention, in one embodiment the non-woven mat comprises (1) a fibrous web of fibrillated fibres comprising both fibrillated feather barb material and fibrillated feather quills; and (2) a thermoplastic binder. The thermoplastic binder may, for example, be a monocomponent fibre or may be a bi-component fibre.

Detailed Description of the Invention

The invention provides a method for absorbing oil, using a non-woven mat that comprises a fibrillated fibre blend, and also provides the use of said non-woven mat to absorb oil.

The method or use may be carried out in an indoor location, such as in a kitchen, restaurant, laboratory or factory, or it may be in an outdoor location, e.g. a body of water such as a lake, river, reservoir, sea or ocean.

It may be that the method or use absorbs oil that is on and/or in an aqueous liquid, such as a body of water. In one embodiment, the oil may have been mixed with an aqueous liquid, such as an oil spill in the sea or ocean, or where there is oil present in a wastewater stream. In one embodiment the non-woven mat is used as a filter, to filter oil out from a liquid.

It may alternatively be that the method or use absorbs oil that is on a solid surface, such as a floor or a worksurface or a kitchen appliance surface. In one embodiment, the oil may have been spilt onto a surface in an industrial or commercial building.

The oil that can be absorbed by the non-woven mat includes, but is not limited to, petroleum oil, petroleum-derived compounds, vegetable-derived oils and animal-derived oils. Specific examples of oils in the context of the invention include crude oil, refined oils such as petrol, diesel and aviation fuel, cooking oils such as sunflower oil, olive oil and fish oil, and solvents such as octanol, hexane and ethyl acetate.

In one embodiment, the non-woven mat is used absorb from oil from a body of water, such as an ocean, sea, river or lake, or a reservoir or a wastewater stream. In one such embodiment, the non-woven mat may be placed on the surface of a body of water, e.g. a sea or ocean, to prevent or reduce the spread of an oil spill. In this embodiment the oil may come into contact with the non-woven mat without requiring any further intervention, e.g. due to movement caused by the tide and/or waves and/or the natural spread of oil over the water. It may optionally be that additional action is taken to move the non-woven mat into contact with the oil, e.g. by use of a pulley or winch system, or by towing the mat into position such as by use of a motorised vessel.

In another such embodiment, the non-woven mat may be placed in the flow path of a contaminated river or stream to absorb oil from the water as it passes through or over the mat.

In another such embodiment, the non-woven mat may be placed in the flow path of a wastewater stream, to absorb oil from the wastewater stream as it passes through or over the mat.

In one embodiment, the non-woven mat is used absorb from oil from a solid surface. This may be in an industrial or commercial setting, or may be in a domestic setting where the method is being carried out commercially, e.g. by a commercial cleaning service. No claim is made to methods for personal and non-commercial use.

The non-woven mat may, for example, be provided in the form of a wipe, cloth, towel or mophead. The non-woven mat may be used to absorb spilt oil from a solid surface, e.g. by bringing the mat into contact with the oil on the surface and wiping the surface until the oil has been absorbed into the mat. Thus, an individual person can readily clean up a small-scale spillage of oil.

The non-woven mat can be used manually, but it will also be appreciated that the non-woven mat can be used in an automated method of cleaning up, e.g. with a robot or other automated machinery carrying out the method.

In one embodiment, the method comprises the additional step of compressing the non-woven mat to expel some or all of the oil that has been absorbed.

In one embodiment, the method comprises the additional step of washing the non-woven mat to expel some or all of the oil that has been absorbed.

In one embodiment, the non-woven mat is re-used. The re-use may be to absorb oil in the same setting or in a different setting. The re-use may be carried out after some or all of the absorbed oil has been expelled from the mat. The mat may be re-used once or multiple times, e.g. 5 or more times, or 10 or more, or 25 or more, or 50 or more times.

Fibrillated fibre blend

Feathers from any avian species may be used, but examples are feathers from chickens, turkeys, quails, ducks, geese, pigeons, doves, pheasants, emu, swans, and ostriches. In one embodiment, the feathers are from chickens or ducks or geese or turkeys.

The term “feather” includes, but is not limited to, primary feathers, secondary feathers, tail feathers, contour feathers, down feathers, filoplumes, semiplume feathers, and bristle feathers.

The fibrillated fibre blend comprising both fibrillated feather barb material and fibrillated feather quills may have fibres with a diameter of from 1 micron to 200 microns, e.g. from 1 micron to 100 microns, such as from 10 microns to 100 microns.

In one embodiment the fibres in the fibrillated fibre blend have a Young’s Modulus strength from 2.5 to 4GPa and a tensile strength from 41 to 130MPa. These values can be measured according to the “ISO 14577 Test Method”. The measurements may be obtained using a universal testing machine that employs a nanomechanical actuating transducer head to produce tensile force using electromagnetic actuation combined with a capacitive gauge, such as the Agilent T150 UTM.

In one embodiment the fibrillated fibre blend exhibits a temporary hydrophobic behaviour in water. This is consistent with the fact that keratin contains hydrophobic and hydrophilic groups. Hydrophobic behaviour can be assessed using a contact angle measurement goniometer, such as the rame-hart Model 590.

In one embodiment the fibrillated fibre blend comprises fibres having a shape which is a crimped rectangular fibre, having branched barbules and booklets spreading from the barb. This can be seen by using SEM and by using stereomicroscopy, such as by use of the Phenom SEM Pro and the Leica M205 C microscope.

Obtaining the fibrillated fibre blend

A fibrillated fibre blend can usefully be obtained by the process described in W02017/221015A1 using a hammer mill. Thus, the process of the third aspect may involve steps (A-i) to (A-iv), as noted above. In this process whole feathers are provided in a non-chemically treated form. Preferably the feathers as provided in step (A-i) are a by-product from a poultry-processing plant. The term “poultry” is intended to refer to any kind of domesticated bird, captive-raised for its utility, and includes but is not limited to, chickens, turkeys, geese and ducks.

In the embodiment where the feathers that are used are a by-product from a poultry-processing plant, the feathers are collected while still fresh (less than 24-hours after being plucked from the bird, e.g. less than 12-hours after being plucked). These are either used directly in the present process or alternatively are rinsed with water, and then stored in a cool environment (e.g. from 5 to 20 °C) which is preferably not in direct sunlight before being used in the present process.

The feathers as used are in a non-chemically treated form. Therefore, they have been plucked from the bird and either are used directly or alternatively the only processing of the feathers after plucking is one or more of rinsing, drying and storing.

It is intended that the feathers as provided in step (A-i) are whole, i.e. they include the two vanes attached on either side of the quill. In addition, it is intended that the feathers remain in whole form during steps (A-ii) and (A-iii). It is intended that the feathers should be whole, with two vanes still being attached on either side of the quill, when they are milled in step (A-iv).

In one embodiment steps (A-i) to (A-iv) are carried out at the poultry-processing plant. In another embodiment steps (A-i) to (A-iii) are carried out at the poultry-processing plant and the dried feathers as obtained from step (A-iii) are then transported from the poultry-processing plant to a separate treatment location before carrying out step (A-iv). In another embodiment feathers are transported from a poultry-processing plant to a separate treatment location before carrying out steps (A-i) to (A-iv).

Any one or more of the steps (A-i) to (A-iv) may be carried out batchwise or continuously. In particular, the milling step (A-iv) may be carried out as a batch process or may be run as a continuous process.

In step (A-ii) the feathers as obtained from step (A-i) are washed with an aqueous liquid at elevated temperature. In one embodiment the elevated temperature is 30 °C or more, such as 40 °C or more or 50 °C or more. In one embodiment the elevated temperature is 60 °C or more, such as 70 °C or more or 80 °C or more. It may be that the elevated temperature is from 50 to 150 °C, such as from 60 to 130 °C or from 70 to 120 °C. In one embodiment the elevated temperature is from 70 to 110 °C, such as from 75 to 100 °C or from 80 to 100 °C. The aqueous liquid may comprise water and surfactant, for example it may comprise 90 wt.% or more water and from 0.1 to 10 wt% surfactant. In one embodiment it comprises 95 wt.% or more water and from 0.5 to 5 wt.% surfactant, e.g. 97 wt.% or more water and from 0.5 to 3 wt.% surfactant.

The surfactant may be anionic or cationic or non-ionic. The surfactant may, for example, be an anionic surfactant such as an alkylbenzenesulfonate, for example a C8-C24 alkylbenzenesulfonate, especially a C8-C18 alkylbenzenesulfonate, in particular a CIO, 11 or 12 alkylbenzenesulfonate. In one embodiment it is a linear alkylbenzenesulfonate. The surfactant may alternatively be a non-ionic surfactant, such as a primary alcohol ethoxylate surfactant (e.g. a C8-C24 primary alcohol ethoxylate, especially a C8-C18 primary alcohol ethoxylate, such as a CIO, 11 or 12 primary alcohol ethoxylate) or an alkylphenol ethoxylate surfactant (e.g. a C8- C24 alkylphenol ethoxylate, especially a C8-C18 alkylphenol ethoxylate, such as a CIO, 1 1 or 12 alkylphenol ethoxylate). However, the present invention is not limited to a specific surfactant type and the skilled person will be aware of surfactants as used in domestic and industrial settings that can wash animal-derived materials such as wool and feathers.

The aqueous liquid may also comprise one or more enzymes, as is known in biological detergents. These may suitably be alkaline enzymes. For example, the enzymes may be one or more of a-amylase, cellulase, protease, lipase and mannase. Enzymes that are suitable for use in this regard are described in Methods in Biotechnology, Vol. 17: Microbial Enzymes and Biotransformations, 2005, pp 151-161.

The enzymes may be used in the aqueous liquid a level of from 0.0001wt% to 0.5wt%, e.g. from 0.0005wt% to 0.1wt%, such as from 0.001wt% to 0.02wt%.

The washing step may be carried out for 30 minutes or more, such as an hour or more or 90 minutes or more. In one embodiment the washing step is carried out for from 1 to 5 hours, such as from 1 to 3 hours.

In step (A-iii) the washed feathers as obtained from step (A-ii) are dried. This may involve heating to a temperature of 50 °C or more, such as 60 °C or more or 70 °C or more. It may be that the heating is from 50 to 150 °C, such as from 60 to 130 °C or from 70 to 120 °C. In one embodiment the heating is from 70 to 110 °C, such as from 75 to 100 °C or from 80 to 100 °C. The heating may be carried out in an oven or other suitable equipment. In one embodiment, step (A-iii) is carried out at the poultry-processing plant and the heating is carried out using waste heat from the poultry-processing plant.

The heating may be carried out for an hour or more, such as two hours or more or three hours or more, or four hours or more. In one embodiment the heating is carried out for from 2 to 48 hours, such as from 4 to 40 hours or from 8 to 36 hours or from 10 to 30 hours.

It may be that the feathers undergo spin drying before heating, in order to remove excess moisture. For example, the feathers may be spin dried for 2 minutes or more, such as 3 minutes or more or 4 minutes or more or 5 minutes or more. In one embodiment the feathers may be spin dried for from 2 minutes to 1 hour, such as from 5 minutes to 30 minutes.

The spinning may be at any suitable speed, e.g. from 500 to 1500 rpm, such as from 700 to 1400 rpm or from 800 to 1300 rpm or from 900 to 1200 rpm.

Preferably in step (A-iii) 90 wt% or more of the aqueous liquid from washing is removed from the feathers, such as 95 wt% or more or 98 wt% or more or 99 wt% or more or 99.5 wt% or more.

In one embodiment, the feathers are weighed before step (A-ii) and are weighed again after step (A-iii), to ensure that most or all of the moisture from the washing step has been removed.

In step (A-iv) a dry milling process is used to generate a fibre blend from the feathers. In this regard, a hammer mill is used.

As discussed above, the use of a hammer mill with specific process parameters results in a fibrillated fibre blend comprising both fibrillated feather barb material and fibrillated feather quills.

The process step (A-iv) does not make use of mills that crush or chop or cut (e.g. a cutting mill or a disk mill). A mill having a beating or impacting action is essential. Furthermore, the use of dry feathers in the milling is essential.

The process step (A-iv) makes use of a hammer mill. As the skilled person will appreciate, a hammer mill comprises a casing having an inlet end, a discharge end, a longitudinal axis passing between the inlet and discharge ends, and a sidewall substantially encapsulating the axis between the inlet and discharge ends, such that an enclosed grinding space is defined within the casing. A rotor assembly is provided for rotation about the axis, and includes a rotatable shaft on the axis, support means extending radially from the shaft for co-rotation therewith, and hammer elements attached to the support means, the hammer elements each having a radially outer tip which defines a hammer rotation diameter. At least one grinding plate at the inside of the sidewall defines a grinding surface in the grinding space having a radius of curvature centred on the axis, a length dimension parallel to the axis, and a width dimension defined by an arc about the axis. Each hammer tip passes along the width dimension of the grinding plate with a clearance from the grinding surface, which defines a grinding gap. The grinding gap is adjustable, e.g., by movement of the grinding plates towards and away from the axis. In use, the material is impacted by the rotating hammers and the hammers force the material against a screen. The screen has sized apertures through which the material passes once it has been ground to a small enough size.

Thus, the hammer mill as used in process step (A-iv) is of a conventional type, but the grinding gap and the apertures for the screen have been selected to achieve the desired characteristics in the end product. By the selection of these parameters a fibrillated fibre blend is obtained comprising both fibrillated feather barb material and fibrillated feather quills.

The screen may have a curved profile, e.g. to match the profile of the casing/ grinding surface.

The screen may be provided with an array or grid of apertures; thus, there may be multiple rows of apertures. The apertures may be provided in a spaced array extending down most or all of the length of the screen and extending across most or all of the width of the screen. In one embodiment the apertures are provided in a regularly spaced array.

In one embodiment the screen has 20 or more apertures, such as 25 or more, or 30 or more, or 40 or more, or even 50 or more, e.g. 60 or more, or 70 or more apertures. These may be regularly spaced across the screen.

In one embodiment, the apertures are provided at a frequency across the surface area of the screen such that per 10cm x 10cm area of the screen, there are 20 or more apertures, such as 25 or more, or 30 or more, or 35 or more apertures.

For example, it may be that for a screen with apertures having a 10mm diameter, per 10cm x 10cm area of the screen, there are 35 or more apertures, such as from 36 to 50 apertures. For example, it may be that for a screen with apertures having an 8mm diameter, per 10cm x 10cm area of the screen, there are 50 or more apertures, such as from 60 to 70 apertures.

For example, it may be that for a screen with apertures having a 5mm diameter, per 10cm x 10cm area of the screen, there are 90 or more apertures, such as from 100 to 100 apertures.

In one embodiment the distance between adjacent apertures is no more than twice the diameter of the aperture, such as no more than 1.5 times the diameter of the aperture. In one embodiment the distance between adjacent apertures is less than or equal to the diameter of the aperture. In one embodiment the distance between adjacent apertures is 10mm or less, e.g. from 5mm to 10mm.

The screen may have a thickness of 1mm or more, such as 2mm or more, e.g. from 1mm to 15mm and especially from 2mm to 10mm. Within these ranges, thicker screens will be used for heavy duty industrial machines whilst thinner screens can be utilised for small hammer mills.

No chemical pre-treatment of the feathers is required. They may be disinfected, but this is not classed as a chemical treatment.

The milling may be carried out as a dry milling process at atmospheric temperature and pressure. The milling atmosphere may suitably be air.

The hammer mill uses a plurality of rotating hammers to force the feathers against a curved grinding surface having raised teeth. A conventional hammer mill may be used. This may, for example, have three or more rotating hammers, such as four or more, or five or more, or six or more. The curved grinding surface may be the inside surface or a barrel shaped chamber. The teeth may be provided at regular intervals. In one embodiment the curved grinding surface is provided with twenty or more raised teeth, such as thirty or more, or forty or more.

The minimum clearance as a hammer tip passes over the grinding surface defines a grinding gap. This grinding gap is known in the art of hammer mills. In the present invention it is important that this grinding gap is from 1mm to 6mm, such as from 2mm to 6mm. In one embodiment it is from 1mm to 5mm, such as from 2mm to 5mm. In one embodiment it is from 1mm to 4mm, such as from 2mm to 4mm. Particularly beneficial results can be obtained when the grinding gap is 5mm or less and especially 4mm or less. The ground feather material is forced out of the mill through screen perforations by the action of the rotating hammers. This use of screen perforations is known in the art of hammer mills. In the present invention it is important that the screen perforations are substantially circular with a diameter of from 3mm to 10mm. In one embodiment the screen perforations have a diameter of from 3mm to 9mm, such as from 3mm to 8mm or from 4mm to 8mm, e.g. from 5mm to 8mm.

It will be appreciated that a hammer mill can be run continuously because the fibres exit the mill via the screen once they have been milled sufficiently to exit the apertures.

In one embodiment the hammer mill is run to result in an output of fibrillated fibres of 10 kg per hour or more, such as 25 kg per hour or more, or 30 kg per hour or more, or 50 kg per hour or more, or 75 kg per hour or more; e.g. from 80 to 300 kg per hour or from 100 to 200 kg per hour.

The hammer mill may be operated at any suitable speed. The best results in terms of the fibre blend being optimal for use in an air laid product have been obtained when the hammers are rotated at a speed of from 200 to 3000 rpm, e.g. from 500 to 3000 rpm and especially from 1000 to 3000 rpm, e.g. from 1000 to 2000 rpm. These rotation speeds allow for fibrillation of the fibres to occur whilst avoiding thermal degradation.

The fibrillated fibre blend comprising both fibrillated feather barb material and fibrillated feather quills as obtained by the invention may have fibres with a length of from 1mm to 2cm, e.g. from 1 mm to 1cm, such as from 5 mm to 1 cm. This can be determined by sieving or by air classification.

Forming the non-woven mat

The mat is formed by the steps of:

(B) depositing the fibrillated fibre blend to form a web of fibrillated fibres; and

(C) carrying out a web consolidation step, to obtain a non-woven mat.

The web formation step (B) may, for example, involve one or more of carding, air laying, wet laying, spun-bonding, melt-blowing or electro-spinning. These are techniques that are known in the art to the skilled person.

In one embodiment a wet-laid manufacturing process is used.

In one preferred embodiment an air-laid manufacturing process is used. It may be that this is a preferred process for achieving excellent properties. Without being bound by theory, it is believed that improved oil-absorbency is achieved by using air-laying because it is possible to form larger pore sizes with this technique as compared to other non-woven techniques. In addition, air-laid nonwoven formation involves no aqueous steps; this minimises the possibility that the feather material is hydrated during processing into may form. It is believed that hydration of the feather material during the mat formation may inhibit oil absorbance.

In one embodiment the fibrillated fibre material may be formed into a web by air carding. This may utilise carding brushes in combination with air jets. This may, for example, be carried out using an air forming head of the type described in EP2238281.

The web consolidation step (C) may, for example, involve one or more of thermal bonding, chemical bonding, needle punching, or spun-lacing. These are techniques that are known in the art to the skilled person.

In one embodiment, step (C) involves application of a temperature of 70°C or more, in particular 80°C or more, such as 100°C or more, 110°C or more, 120°C or more, or 130°C or more.

In some embodiments, step (C) involves application of a temperature of from 70°C to 300°C, such as from 70°C to 250°C, or from 70°C to 200°C, or from 70°C to 180°C; it may be that the temperature is from 80°C to 300°C, from 80°C to 250°C, from 80°C to 200°C or from 80°C to 180°C. In some embodiments, step (C) involves application of a temperature of from 100°C to 200°C, e.g. from 120°C to 200°C or from 130°C to 200°C.

In one preferred embodiment, in steps B) and C) an air-laid manufacturing process is used to form a non-woven mat from a mixture of the fibrillated fibre blend and a thermoplastic binder. The binder is described further below, and in particular it may be a polymeric fibre such as a mono-component fibre or a bi-component fibre; in one embodiment it may be biodegradable.

It may suitably be that the air-laid process comprises the following steps: i) mixing the fibrillated fibre blend and a thermoplastic binder in the form of a polymeric fibre, to obtain a mixture; ii) using air to carry the mixture and deposit it onto a surface, to form a web of fibrillated fibres; Hi) heating the deposited web to cause bonding of the binder, to consolidate the web; and iv) allowing the consolidated web to cool, to obtain the non-woven mat.

It will be appreciated that in such a process, steps i) and ii) fulfil the requirements of step (B) of depositing the fibrillated fibre blend to form a web of fibrillated fibres. It will likewise be appreciated that in such a process, steps iii) and iv) fulfil the requirements of step (C) of carrying out a web consolidation step, to obtain a non-woven mat.

Therefore, in one embodiment, the process for obtaining an oil-absorbent non-woven mat comprises the steps of:

A) providing a fibrillated fibre blend comprising a mixture of both fibrillated feather barb material and fibrillated feather quills;

B) i) mixing (1) the fibrillated fibre blend and (2) a thermoplastic binder in the form of a polymeric fibre, to obtain a mixture; and ii) using air to carry the mixture and deposit it onto a surface, to form a web of fibrillated fibres; and

C) iii) heating the deposited web to cause bonding of the binder, to consolidate the web; and iv) allowing the consolidated web to cool, to obtain the non-woven mat.

When step i) is carried out this may result in a mixture of the fibrillated fibre blend and the polymeric fibre thermoplastic binder that is structurally amorphous but compositionally homogenous. In this regard, the skilled person will appreciate that the mixture is structurally amorphous in the sense that there is no regular arrangement, as compared with, for example, a crystal structure. There is, therefore, randomness in the alignment of the fibrillated fibres. However, the mixture is compositionally homogeneous in the sense that in any given sample of the mixture, the proportion of binder to fibrillated feather is substantially the same.

Step i) may suitably be achieved by mixing the fibrillated fibre blend and the thermoplastic binder in a mixing air column. However, other known ways of mixing fibres may be used.

In step ii) the mixture may be blown or carried by air onto the surface, or the mixture may be dropped onto the surface by gravity, or the mixture may be drawn to the surface by use of a vacuum force. In one embodiment, the mixture is carried by air flow from a mixing air column to a surface.

In one embodiment, in step ii) the surface is a conveyor belt.

In one embodiment, in step iii) the deposited web is transported into an oven to heat the binder. It may, for example, be that the deposited web is transported into and through an oven by a conveyor belt.

The temperature for heating in step iii) is described in relation to step C) above. When a conveyor belt is used, the speed of the belt may be adjustable. Varying the speed of the belt can allow for control and variation of height and density for the mat that is formed.

In one embodiment, in step iv) cooling panels may be used to cool the consolidated web.

In step iv), the cooling of the web acts to fix the textile into its permanent structure, i.e. in the form of a non-woven mat.

The cooling in step iv) may suitably be to approximately room temperature, e.g. the web may be allowed to cool to a temperature in the range of from 10°C to 30°C, or from 15°C to 25°C.

The process of the third aspect includes steps A)-C). In one preferred embodiment, the process further comprises the step of pressing the non-woven mat to achieve a desired thickness and/or a desired density.

It may be that the pressing step is carried out to achieve a density of 25 kg/m ³ or more, e.g. 40 kg/m ³ or more, preferably 50 kg/m ³ or more. In one embodiment, the pressing step is carried out to achieve a density of 60 kg/m ³ or more, preferably 70 kg/m ³ or more, or 80 kg/m ³ or more, e.g., 100 kg/m ³ or more, or 125 kg/m ³ or more, or 140 kg/m ³ or more, or 150 kg/m ³ or more, or even 200 kg/m ³ or more. It may be that the density is from 25 kg/m ³ to 500 kg/m ³ e.g. from 40 kg/m ³ to 450 kg/m ³ or from 50 kg/m ³ to 425 kg/m ³ or from 60 kg/m ³ to 400 kg/m ³ . It may be that the density is from 25 kg/m ³ to 300 kg/m ³ e.g. from 40 kg/m ³ to 250 kg/m ³ or from 50 kg/m ³ to 225 kg/m ³ or from 60 kg/m ³ to 150 kg/m ³ . Densities can be measured manually with a calliper, measuring tape and a microbalance.

In one embodiment, the pressing step is carried out to achieve a thickness of 50mm or less, such as 40mm or less; e.g. from 0.5mm to 50mm or from 1mm to 40mm. A pillow or boom may, for example, have a useful thickness of about 30 to 40mm, and a wipe may, for example, have a useful thickness of about 1 to 3mm.

It may be that in one embodiment the pressing step is carried out to achieve a thickness of 8mm or less, such as 6mm or less, preferably 5mm or less, such as 4mm or less, or 3mm or less, or 2mm or less. The pressing step increases the density of the mat formed from fibrillated fibre material. It may be that the density is increased by 1.5x or more, preferably 2x or more, such as 3x or more, or 4x or more, e.g. 5x or more, or 6x or more.

The pressing step may involve an application of pressure for 1 minute or more, or 2 minutes or more, preferably 5 minutes or more, e.g. 8 minutes or more, or 10 minutes or more, such as 15 minutes or more.

The pressing step may, in one embodiment, involve an application of pressure of 0.5 MPa or more, or 1 MPa or more, such as 2MPa or more, or 3MPa or more, or 5MPa or more, e.g. lOMPa or more. It may be from 0.5 to 20MPa, e.g. from 1 to 15 MPa.

Additional components for the non-woven mat

In some embodiments, the non-woven mat comprises (1) a fibrous web of fibrillated fibres comprising both fibrillated feather barb material and fibrillated feather quills; and (2) a thermoplastic binder. The thermoplastic binder may be combined with the fibrillated fibre blend before, during or after step (B).

Particularly beneficial results can be obtained by using this combination of thermoplastic binder and fibrillated fibre blend. This non-woven mat has excellent oil absorbency, re-usability, and aesthetic properties.

The thermoplastic binder may, for example, be provided in the form of a liquid or in the form of a polymeric fibre, e.g. a mono-component fibre or a bi-component fibre. The use of a polymeric fibre may be preferred and can lead to a non-woven mat having excellent oil absorbent properties. In one embodiment the fibre may have a denier of from 0.5 to 18, e.g. from 1 to 10.

When considering the mixture of fibrillated fibres and binder, the binder may, for example, be used in an amount of from 1 to 75 wt.% of the mixture, such as from 2 to 70 wt.%, or from 3 to 60 wt.%; preferably from 5 to 50 wt.%, e.g. from 10 to 50 wt.%. In one embodiment the binder is used in an amount of from 5 to 30 wt.%, or from 10 to 30 wt.%, or from 10 to 25 wt.%.

The thermoplastic binder may, in one embodiment, include a polymer selected from the group consisting of: polylactic acid (PLA), poly(butylene succinate) (PBS), polyethylene terephthalate (PET), polyvinyl alcohol (PVOH), poly-P-hydroxybutyrate-co-P-hydroxy valerate (PHBV), polyglycolic acid (PGA), poly(e-caprolactone) (PCL), nylon-2-nylon-6, polyethylene (PE), polypropylene (PP), polysaccharides (especially seaweed-derived polymers, such as carrageenan, agar, and/or alginate), polyvinylacetates, polyesters and combinations thereof. For example, a binder selected from PLA, PBS, PE, PET and PVOH and combinations thereof (e.g. PLA/PBS, or PBS, or PE/PET) may be used.

In one embodiment a thermoplastic binder that is biodegradable is used. For example, PLA, PBS, PVOH, PET, PCL, nylon-2-nylon-6, PHBV, PGA and polysaccharides are all examples of biodegradable fibres that can be used individually, e.g. in mono-component fibres, or in combination, e.g. in bi-component fibres.

If the thermoplastic binder is in liquid form, a spray impregnation process may be used. Thus, the thermoplastic binder may suitably be sprayed onto the web as obtained in step (B) either before step (C) is carried out or during step (C).

If the polymeric binder is in a fibrous form, e.g. a mono-component fibre or a bi-component fibre, then this may suitably be formed into a web together with the fibrillated feather fibres during step (B), e.g. by air laying or wet laying the mixture of fibres. Air laying may be preferred in some embodiments as an effective process for obtaining good properties.

As the skilled person will be aware, bi-component fibres comprise two different polymers in a single fibre. Bi-component fibres can be provided in a number of forms, depending on the respective locations of the two components in the fibre. These include: side-by-side, sheathcore, segmented pie, islands in the sea, tipped, or segmented ribbon. A sheath-core form can be useful as it provides a first polymer in the core of the fibre which is then circumferentially surrounded by the second polymer.

Examples of bi-component fibres include: polylactic acid/poly(butylene succinate); polyethylene/polypropylene; polyethylene/polyester (especially polyethylene terephthalate); polypropylene/polyester; copolyester/polyethylene terephthalate, such as polyethylene terephthalate-isophthalate/polyethylene terephthalate; nylon 6/nylon 6,6; or nylon 6/polyethylene terephthalate.

In one embodiment the bi-component fibre may comprise a sheath polymer that has a melting point of 170 °C or less, such as 160 °C or less, or 150 °C or less, or 140 °C or less. For example, the polymer used as the sheath may have a melting point of from 90 to 150 °C or from 100 to 140 °C. The bi-component fibre may, in one embodiment, be in sheath-core form and consist of a core fibre of a first polymer and an outer layer of a second polymer, wherein the first polymer has a higher melting point than the second polymer. Utilising this kind of fibre is technically beneficial. The fibrillated feather fibres can then bond with the low melting point polymer (e.g. polyethylene) on the outside of the fibre at low temperatures, therefore avoiding thermal degradation.

In one embodiment one or more additives are also included in the non-woven mat. These additives may be combined with the fibrillated fibre blend before, during or after step (B). Liquid additives may, in one embodiment, be introduced through bath impregnation or spray impregnation of the web as formed in step (B). Additives in solid form may, in one embodiment, be mixed with the fibrillated fibre blend before or during step (B). Additives may optionally have been pre-combined with the thermoplastic binder, e.g. the thermoplastic binder may be a bi-component fibre provided in combination with one or more additive.

Additives may, for example, be included to improve the feel and/or texture of the product. They may alternatively or additionally alter other properties of the product, e.g. biodegradation properties.

One example of additives that can be included are biobased additives to tailor the absorbent properties. These may be additives that have hydrophobic or hydrophilic properties. The hydrophobic/hydrophilic balance may be chosen to achieve desired properties. The additives may be added through dry powder impregnation or spraying.

Another example of additives that can be included are antimicrobials. They may be added through dry powder impregnation or spraying.

A further example of additives that can be included are malodour inhibitors. They may be added through dry powder impregnation or spraying.

Another example of additives that can be included are biobased additives to tailor the biodegradation properties.

Oil-absorbent product

The non-woven mat may be provided in the form of an oil-absorbent product. The oil-absorbent product may, for example, be a wipe, cloth, towel or mophead; or a roll or boom; or a filter.

In some embodiments, the oil-absorbent product further comprises a container enclosing the non-woven mat; for example, the non-woven mat may be contained within a closed sack, the sack being formed from cloth. The cloth is porous to both oil and water. In some embodiments the cloth is biodegradable. In some embodiments, the biodegradable cloth is selected from jute, cotton, wool, flax, hemp, rattan or combinations thereof. In other embodiments the cloth is not biodegradable, such as a polypropylene cloth.

In some embodiments, the container has a resealable opening through which the non-woven mat may be removed and replaced. The opening may be sealable by, for example, hook and loop fasteners, interlocking teeth, or press studs, or by any other resealable closing mechanism.

In some embodiments the product is an oil-absorbing boom. The oil-absorbing boom may be tubular in shape. The oil-absorbing boom may, for example, have a diameter (maximum cross section) of 0.1 or 0.2 metres or more, such as 0.5 metres or more, or 1 metre or more. The oilabsorbing boom may, for example, have a length of 1 metre or more, such as 2 metres or more, or 10 metres or more, or 50 metres or more.

In some embodiments the oil-absorbing boom may comprise additional buoyancy aids to support the product in the water. These may be positioned within the non-woven mat, within a container enclosing the non-woven mat, or attached to the outside of the container. Buoyancy aids are known in the art, for example air-containing capsules formed from HDPE, LDPE or stainless steel or any suitable material.

In some embodiments, the product is a wipe, cloth, towel or mophead. It may be suitable for absorbing spilt oil from a solid surface, e.g. by bringing the product into contact with the oil on the surface and wiping the surface until the oil has been absorbed into the product. Thus, an individual person can readily clean up a small-scale spillage of oil.

The wipe, cloth, towel or mophead may have any suitable cross-sectional shape, for example the cross-section may be square or rectangular. The wipe, cloth, towel or mophead may have any suitable dimension but in one embodiment the maximum dimension is in the range of from 10cm to 100 cm, such as from 15cm to 90cm or from 20cm to 80cm. The wipe, cloth, towel or mophead may, for example, have a thickness of from 0.5mm to 3cm, such as from 1mm to 2cm or from 2mm to 1cm. A mophead may be formed from a single non-woven mat but could also be in the form of multiple non-woven mats, e.g. extending as multiple strips from a base.

The invention will now be further described with reference to the following non-limiting examples:

Examples

Example 1 : Making and testing a fibrillated fibre non-woven mat

Obtaining feathers

Feathers, e.g. chicken feathers, are taken from a slaughterhouse waste disposal line, where the feathers have been compacted. These are used whole whilst still fresh (less than 24 hours since being plucked).

Washing feathers

The feathers are washed in a cylindrical washing machine containing water with 1% biological detergent at 90 “Celsius for 2 hours.

Drying feathers

The washed feathers are spun in the same washing machine on a spin cycle, for 8 minutes at 1200rpm, to remove excessive moisture.

The feathers are then dried at 80°C for 24 hours in an oven to remove all moisture content.

Hammer mill process - fibrillated feather fibre production

A Christy Turner X15 Crossbeater hammer mill, with a 55kW motor, was used. The mill contained two screens with curved/semi-circular profiles, each with rows of apertures that are 8mm diameter round holes. The apertures are provided as a regularly spaced array and per 10cm x 10cm surface area of the screen there are 60-70 apertures. The grinding gap is set to be 3- 4mm.

The hammer mill can be run continuously. 2kg of the dry feathers are milled at a time in the milling chamber. The hammer mill is operated at 3000 rpm. This results in a 100-120kg output of fibrillated fibres per hour. The fibrillated feather fibres are transported via airflow into a cyclone system and can be collected there.

Testing fibrillated fibre blend:

The fibre distribution was analysed with a sieve. The fibrillated fibre blend had fibres with a length of from 1mm to 1cm.

As the skilled person will appreciate, tapped density is determined by mechanically tapping a measuring cylinder (i.e. raising the cylinder and allowing it to drop a specified distance under its own weight) containing the sample under test, and by dividing the sample weight by the final tapped volume. The fibrillated fibre blend has a tapped bulk density, as measured at room temperature using a Copley Jv2000 Tapped Density machine, in the range of from 15 to 30 kg/m ³ .

Formation of a non-woven mat:

The fibrillated fibres were fed directly into a hopped chamber of an air-laid line, which had a fibre opening step via rotary brush belts. The fibrillated fibres were transported onto a weighing system and were then air carded in several steps in mechanical brush carders.

In a forming chamber the fibrillated feather fibres were mixed with PLA/PBS bi-component fibres via vortex air streams. The bi-component fibres were of the sheath-core type and had an outer layer of lower melting point polymer and an inner core of higher melting point polymer.

The mixture was distributed via air suction onto a revolving vacuum belt.

A calendaring roll compacted the fibre mixture on the belt and could be used to adjust the depth of the fibre mixture as needed.

A double belt oven was used to carry out thermal bonding at 140°C. This temperature melted the outer layer of the bi-component fibres, meaning the feather fibres interlocked with the bi- component fibres.

A fibrillated fibre non-woven mat was obtained which was 80wt% feather fibres and 20wt% bi- component fibres.

The PLA/PBS is biodegradable and the mat as a whole is biodegradable according to industrial degradation testing, e.g. according to ASTM 5511 or ASTM 5338. Testing oil absorption properties against polypropylene mesh:

Two separate 600 ml beakers were prepared, each containing a 400ml bottom phase which is aqueous and an 80ml top phase which is vegetable oil.

Into one beaker a 5.2 g sample of a commercial polypropylene mesh was added. Into the other beaker a 5.2 g sample of the fibrillated fibre non-woven mat as described above was added.

The samples were left to absorb the oil for 5 minutes. Following this time, the samples were removed and left to drain for a further 5 minutes. The samples were then weighed to establish the amount of oil absorbed. The results were:

Therefore, the fibrillated fibre non-woven mat of the present invention out-performs polypropylene-based materials with respect to oil-absorbency.

Testing against natural fibre oil sorbents:

The following five samples were tested:

• fibrillated fibre non-woven mat as described above;

• plain whole feathers;

• wool;

• cotton;

• sawdust.

Five separate 500 ml beakers were prepared, each containing a 300 ml bottom phase which is aqueous and a 175 ml top phase which is vegetable oil.

In each case a 100 cm ³ sized sample was prepared and added to one of the beakers and immersed in the beaker’s content.

The samples were left to absorb the oil for 5 minutes. Following this time, the samples were removed and left to drain until no more liquid was observed to drop from the sample. The samples were then weighed to establish the amount of oil absorbed. The results were:

The results show that the fibrillated fibre non-woven mat of the invention provides a significantly higher volumetric sorption than samples of all the tested natural fibre oil sorbents.

Testing against comparative whole feather mat:

A fibrillated fibre non-woven mat as described above (80wt% fibrillated feathers and 20wt% bicomponent binder PLA/PBS) was provided. A comparative non-woven mat was prepared that was 80wt% whole feathers and 20wt% bi-component binder PLA/PBS. Both samples weighed approximately 3.2g.

Two separate 1000 ml beakers were prepared, each containing a 400 ml bottom phase which is aqueous and a 400 ml top phase which is vegetable oil. Each beaker was placed on a balance and the total weight of the filled beaker recorded.

Each sample was placed on a suspended sieve and then lowered into one of the prepared beakers. Each sample was left immersed in its beaker for 30 seconds, as timed using a stopwatch. The sieve was then raised to lift the mat up out of the beaker, and the sample was left to drain over the beaker until no more liquid was observed to drop from the sample. The weight of each beaker was then recorded again.

The steps of lowering and immersion, lifting and draining, and then weighing the beaker, were repeated as a cycle until the samples were completely saturated.

The measured weight of each beaker at after each cycle allowed the oil sorption in grams to be determined each time interval.

The results are shown in Figure 1, which is a graph of oil sorption (g) against time (minutes) for both the fibrillated fibre non-woven mat that was 80wt% fibrillated feather fibre and 20wt% bicomponent binder, and the comparative non-woven mat that was 80wt% whole feathers and 20wt% bicomponent binder. The results show that the non-woven mat made of fibrillated feather fibre absorbed oil at a faster rate than the non-woven mat made from whole feathers.

Testing against previously described whole feather-based oil sorbents:

Tests are also carried out to compare the oil absorbency of the fibrillated fibre non-woven mat with whole feather-based oil sorbent materials as previously described in the art.

The fibrillated fibre non-woven mat of the present invention out-performs whole feather-based oil sorbent materials with respect to oil-absorbency.

In addition, based on a visual assessment the fibrillated fibre non-woven mat is more homogeneous and visually appealing than a whole feather-based oil sorbent materials as described in the art. There are no sharp quills to cause damage or injury.

The fibrillated fibre non-woven mat is re-used multiple times and remains effective as an oil absorbent. In contrast, when the whole feather-based oil sorbent material is re-used, fracturing and/or tearing occurs over time.

Testing against previously described chopped and powdered feather-based oil sorbents:

Tests are also carried out to compare the oil absorbency of the fibrillated fibre non-woven mat with feather-based oil sorbent materials as previously described in the art (using 10mm chopped lengths of washed and dried feathers) and powdered feather-based oil sorbent materials as previously described in the art (using finely ground feathers).

The fibrillated fibre non-woven mat of the present invention out-performs chopped/ground feather-based oil sorbent materials with respect to oil-absorbency.

Without being bound by theory, it is believed that the fibrillated fibres used according to the invention have primary, secondary and tertiary branches, and that this results in an increased internal fibre surface area and an increased number of pores. These factors both aid total oil absorption.

Example 2: Making and testing different mat compositions a) Making and testing oil absorption: Example 2 followed the same approach as Example 1 to obtain fibre mats for testing. This Example made five mats with the following different amounts of bi-component fibre: 10, 15, 20, 25 and 30 weight %. In each case the balance to 100% was fibrillated feather fibre.

A batch of five comparative non-woven mats were also produced, with the same amounts of bicomponent fibre but with whole feathers instead of fibrillated feather fibre.

Each sample had an approximate mass of 2.5 g.

Ten separate 500 ml beakers were prepared, each containing a 300 ml bottom phase which is aqueous and a 175 ml top phase which is vegetable oil.

Each sample was added to one of the beakers and immersed in the beaker’s content. The samples were left to absorb the oil for 5 minutes. Following this time, the samples were removed and left to drain until no more liquid was observed to drop from the sample. The samples were then weighed to establish the amount of oil absorbed.

The experiment was repeated three times and the results averaged.

The results are shown in Figure 2, which is a graph of volumetric oil sorption (g/cm ³ ) against the weight percentage of bi-component fibre for both the fibrillated fibre non-woven mats and the comparative non-woven mats.

The results show that, for all proportions of bi-component fibres tested, the non-woven mat made of fibrillated feather fibre absorbed more oil than the equivalent non-woven mat made from whole feathers. b) Testing re-use of the mats:

The ten samples as obtained after testing in part a) above were manually pressed to release the absorbed oil content.

The samples were washed in hot water containing a detergent (lg/L ‘Felosan Fox’ from CHT Germany GmbH) at approximately 45°C. This step was repeated two times before rinsing with hot water (about 45°C).

The samples were then placed into a dehydrator at about 70°C for 4 hours to ensure all water was removed. The weight of each sample was recorded. The washed and dried samples were inspected visually. It was found that non-woven mats made from whole feathers mechanically degraded following the washing procedure and had a deteriorated aesthetic appearance. In contrast, the non-woven mats made from the fibrillated feathers did not significantly deteriorate/degrade.

The washed and dried samples were then tested for oil absorbency in the same manner as in part a) above. The oil absorption capacity of the washed samples was then compared to the oil absorption capacity of the original samples.

The results are shown in Figure 3, which is a graph of the % oil absorption achieved on re-use against the weight percentage of bi-component fibre for both the fibrillated fibre non-woven mats and the comparative non-woven mats.

The results show that, generally, the non-woven mat made of fibrillated feather fibre showed better retention of its oil absorption characteristics after washing and drying than the equivalent non-woven mat made from whole feathers.

Therefore, non-woven mats made from the fibrillated feather fibre provide a better ability to be re-used, in terms of retaining oil absorption, not adversely mechanically degrading and retaining aesthetics.

Example 3: Densifying mats

Example 3 followed the same approach as Example 1 to obtain feather fibre mats for testing.

A first mat was made with 20wt% bi-component fibre and 80wt% fibrillated feather fibre. A second, comparative, mat was made, with the same amount of bi-component fibre but with whole feathers instead of fibrillated feather fibre.

The accessible densities were studied by introducing each sample into a hot-press machine, for 10 minutes at a temperature of 160°C.

The pressing step was repeated until no further change in density was achievable, with the density recorded at each pressing step. The results are shown in Figure 4, which is a graph of the density (kg/m ³ ) achieved against the number of pressings carried out, for both the fibrillated fibre non-woven mats and the comparative non-woven mats.

It can be seen that for the same number of pressings, the mat made from the fibrillated feather fibre achieved higher densities than the equivalent mat made from whole feathers. In addition, the highest achievable density for the mat made from the fibrillated feather fibre (214kg/m ³ ) was significantly greater than the highest achievable density for the equivalent mat made from whole feathers (99kg/m ³ ).

Example 4: Formation and testing of an oil-absorbing wipe

A sample of the fibrillated fibre non-woven mat as described in Example 1, with a thickness of 1 cm, was cut into a 30 x 30 cm square.

This was pressed at 160°C for 12 minutes, until the thickness was approximately 1.5 mm.

This oil-absorbing wipe was tested for oil absorbency as above and was found to absorb oil to the same extent as the fibrillated fibre non-woven mat tested above.

The oil-absorbing wipe was also observed to not absorb any water from the beaker, demonstrating that the material selectively absorbs oil over water.

This oil-absorbing wipe was also used to wipe up an oil spill on a work surface. After being wiped back and forth over the oil spill, the wipe visibly absorbed all of the oil and left the work surface clean.

Example 5: Formation and testing of an oil filter

The fibrillated fibre non-woven mat is also tested as an oil filter. The mat is supported over the mouth of a beaker and a mixture of oil and water is poured through the mat into the beaker.

The oil is absorbed into the filter and the filtrate is water. Thus, the mat is shown to be an effective filter.

Example 6: Testing of mono-component binder a) Oil sorption capacity of mono-component binder feather fibre non-woven mats

Example 6a followed the same approach as Example 1 to obtain fibre mats for testing. However, this Example tested mono-component PBS fibre as the binder. This Example made five mats with the following different amounts of mono-component fibre: 10, 15, 20, 25 and 30 weight %. In each case the balance to 100% was fibrillated feather fibre.

A second set of mats was made where bicomponent PLA/PBS fibre was used instead of the mono-component PBS fibre.

The oil sorption properties were then tested according to the method in Example 2a).

The results are shown in Figure 5, which is a graph of the % oil absorption achieved against the weight percentage of binder for both mono-component fibre and bicomponent fibre-based mats.

The results show that all of the feather-based non-woven mats according to the invention have excellent oil sorption properties. The non-woven mats made with mono-component fibres displayed similar oil absorption properties to those made with bi-component fibres. b) Densifying rate of feather fibre mats made with mono-component binders

The mono-component fibre-based mats and bicomponent fibre-based mats as made with 20wt% binder were each introduced into a hot-press machine, for 15 minutes at a temperature of 160°C, to test their densifying properties.

The results are shown in Figure 6, which is a bar chart showing the density achieved for each of the two samples.

The results show that both samples according to the invention are able to be effectively densified. The sample made with mono-component fibres reaches a higher density in the 15-minute time period, demonstrating an increased rate of densifying over that time frame.

This Example 6 therefore shows that effective feather-based non-woven mats according to the invention can be produced with mono-component fibres as the binder in place of bi-component fibres. The invention can therefore be implemented using mono-component fibres or bi- component fibres as the binder.

The mono-component PBS fibres are biodegradable and the mat as a whole is biodegradable according to industrial degradation testing, e.g. according to ASTM 5511 or ASTM 5338. Example 7: Testing of a further bi-component binder

Example 7 followed the same approach as Example 1 to obtain fibre mats for testing. However, this Example tested bi-component PE/PET as the binder. This Example made five mats with the following different amounts of bi-component fibre: 8, 10, 15, 20 and 25 weight %. In each case the balance to 100% was fibrillated feather fibre.

Two further sets of five mats were made with the same series of fibre content amounts but where (i) bi-component PLA/PBS fibre was used as the fibre binder and (ii) mono-component PBS fibre was used as the fibre binder.

The oil sorption properties were then tested according to the method in Example 2a).

The results are shown in Figure 7, which is a graph of the oil mass absorption capacity (g/g) achieved against the weight percentage of binder for the bicomponent fibre-based mats.

The results show that all of the feather-based non-woven mats according to the invention have excellent oil sorption properties.

The feather-based non-woven mats produced with PE/PET bicomponent fibres display marginally improved oil sorption properties compared to the PBS/PLA sample and the PBS sample. Without being bound by theory, it is thought this may be due to the oleophilic nature of the fibre binder.

The re-use potential of the PE/PET based mats was then tested according to the method in Example 2b).

The results are shown in Figure 8, which is a graph of the % oil absorption achieved on re-use against the weight percentage of PE/PET bi-component fibre for the non-woven mats.

Excellent re-use properties were observed for the PE/PET based non-woven mats according to the invention.

The re-use potential for the PE/PET based non-woven mats was generally similar to the PLA/PBS based non-woven mats as tested in Example 2b). It was also observed that, as compared to PLA/PBS based non-woven mats, a lower amount of bi-component fibre was required to achieve similar levels of strength for the PE/PET based nonwoven mats.

This Example therefore shows that effective feather-based non-woven mats according to the invention can be produced with different bi-component fibres as the binder. The invention can therefore be implemented using a range of binders.

Example 8: Testing of further binders

Example 8 followed the same approach as Example 1 to obtain and test fibre mats. This Example tested the following further mono-component thermoplastic binder fibres: (a) PET and (b) PVOH.

In each case, effective oil absorption is achieved. The fibrillated fibre non-woven mat outperforms whole feather-based oil sorbent materials and polypropylene mesh with respect to oilabsorbency.

In addition, based on a visual assessment the fibrillated fibre non-woven mat is more homogeneous and visually appealing than a whole feather-based oil sorbent materials as described in the art. There are no sharp quills to cause damage or injury.

The fibrillated fibre non-woven mat is re-used multiple times and remains effective as an oil absorbent. In contrast, when the whole feather-based oil sorbent material is re-used, fracturing and/or tearing occurs over time.

The PVOH fibres are biodegradable and the resulting mat is, as a whole, biodegradable according to industrial degradation testing, e.g. according to ASTM 5511 or ASTM 5338.

Example 9 - Testing of mats regarding capillary action

The aim of this example was to investigate whether the higher densities accessible with fibrillated feather fibre materials according to the invention would aid the capillary action, i.e. the ability of oil to move against gravity through the material.

Example 9 followed the same approach as Example 1 to obtain fibre mats for testing. This Example made three mats with 10 wt.% bi-component PLA/PBS fibre and 90 wt.% fibrillated feather fibre. A batch of three comparative non-woven mats were also produced, with the same amount of bi-component fibre but with whole feathers instead of fibrillated feather fibre.

The mats were densified as described in Example 3 but using three different sets of pressing conditions and achieved the following densities:

• fibrillated feather fibre mats: 63.2, 118.62 and 390.3 kg/m ³

• whole feather mats: 17.9, 18.5 and 52.1 kg/m ³ ,

Each of the samples was partially immersed into a 500 ml glass beaker filled with 200 ml of cooking oil and left for 18 hours. Monitoring was carried out during this time to assess the oil sorbency properties.

After 20 minutes, the oil was visibly absorbing up the mat for the fibrillated feather fibre mats with densities of 118.6 kg/m ³ and 390.3 kg/m ³ .

After 40 minutes the fibrillated feather fibre mats with densities of 118.6 kg/m ³ and 390.3 kg/m ³ were becoming saturated, despite not being fully immersed in the oil.

After 18 hours the fibrillated feather fibre mat with density 320.3 kg/m ³ was fully saturated with oil.

After 18 hours, a visual assessment was made of how far up the mat the oil had travelled and this distance from the bottom of the mat was measured. In addition, the mats were weighed to determine the oil absorption (g of oil absorbed per cm ³ of dry mat).

The results are shown in:

Figure 9 which is a graph that shows the g/cm ³ oil absorption for each mat after 18 hours; and

Figure 10 which is a graph that shows the distance up the mat that the oil could visibly be seen to have travelled after 18 hours.

These results show that the denser samples give rise to an increased capillary action.

It is, therefore, beneficial to be able to access much higher densities with the fibrillated feather fibre mats of the invention, because this in turn allows a greater capillary action to be achieved for drawing up oil into the mat against gravity. Example 10 - testing oil sorbency in different water types

The aim of this example was to investigate whether the feather-based mats could operate as effective oil sorbents in a range of different water types, replicating different real-life environments.

The following three water types were tested:

• Tap water, obtained locally from the domestic water supply in the UK.

• River water, extracted locally in the UK.

• Salt water, made in the laboratory by mixing 35 g of NaCl with 1 L of tap water, to represent a seawater environment.

Example 10 followed the same approach as Example 1 to obtain fibre mats for testing. This Example made three mats with 10 wt.% bi-component PLA/PBS fibre and 90% was fibrillated feather fibre. A batch of three comparative non-woven mats were also produced, with the same amount of bi-component fibre but with whole feathers instead of fibrillated feather fibre. The fibrillated feather fibre mats had densities of 21 kg/m ³ and the whole feather mats had densities of 16 kg/m ³ .

For each of the three different water types, two 500ml beakers were prepared which contained a mixture of 200ml of the water sample and 60ml of marine engine oil. The fibrillated feather fibre mat was added to one beaker and the whole feather mat into the other beaker.

In each case, the mat was immersed in the water/oil mixture and left there until saturated with oil. A sieve was then used to lift the mat out and drain off excess oil. The mats were then weighed to determine the oil sorption capacity (g of oil absorbed per g of dry mat).

In each case, the oil sorbency (g/g) of the tested mats in the three different water environments for the fibrillated feather fibre mats was comparable to or better than the whole feather mats.

Therefore the fibrillated feather fibre mats of the invention can operate as effective oil sorbents in a range of different water types, replicating different real-life environments.

Conclusion

Benefits of the present invention are that:

- excellent oil absorption is achieved by providing feathers as fibrillated fibres that are in the form of a non-woven mat. - the non-woven mat exhibits excellent oil absorption, and selectively absorbs oil over water.

- the non-woven mat out-performs polypropylene absorbents with respect to oil absorbency.

- the non-woven mat out-performs whole feathers with respect to oil-absorbency.

- the non-woven mat can be re-used. - the non-woven mat has an improved aesthetic and user experience.

- the non-woven mat has an absence of whole feather quills which avoids damage being caused by sharp quills.

- the non-woven mat is more environmentally friendly than the polypropylene absorbents currently used to treat oil spills. - the non-woven mat remains buoyant in water, even when saturated with oil.

- the non-woven mat can be obtained with higher densities; this allows increased capillary action, for drawing up oil into the mat against gravity, to be achieved.