Method for making wool-based article and article thereof

Abstract

A cured wool article and methods for producing a cured wool article, the method comprising steps: (a) providing wool fibres; (b) performing a hydrolysis reaction on the wool fibres to provide degraded wool fibres; (c) mixing the degraded wool fibres with additional fibres to provide a pre-cured wool mixture, wherein the additional fibres are chopped fibres; and (d) curing the pre-cured wool mixture afford a cured wool article. Also described herein is a cured wool article.

Description

[0001] 008880825

[0002] METHOD FOR MAKING WOOL-BASED ARTICLE AND ARTICLE THEREOF

[0003] Field of the Invention

[0004] The present invention relates to wool-based materials and methods for making wool-based materials. Such materials may be useful, for example, in the construction of buildings or other objects or items which must meet a regulatory standard of physical performance such as mechanical property, thermal conductivity, or flame resistance.

[0005] Background

[0006] It is well-known that there is a growing demand for “greener” technologies, such as technologies which can contribute to a circular resources economy and be repurposed or reprocessed for use at the end of a product lifecycle. For example, there is growing interest in the use of waste materials from one industry as a resource in another industry. Additionally, there is increasing scrutiny on the carbon footprint of new technologies as many counties strive to achieve carbon neutrality.

[0007] Various materials are used in the construction industry, to improve the energy efficiency of buildings (e.g., to reduce heat loss) or just as part of the normal construction, but many known materials have a large carbon footprint and / or are not compatible with a circular resources economy.

[0008] For example, fiberglass is widely used for insulation, and it is the most widely used insulation material in at least the UK. While there is a relatively small carbon footprint associated with the production of fiberglass, it is difficult to recycle and can be a respiratory health hazard. Other commonplace insulation materials face similar issues. For example, concrete insulation — which can be provided as block insulation or foam insulation — is energy- and carbon-intensive to produce and recycle.

[0009] Plant and animal fibres, such as cellulose or wool, are readily sustainable resources for production of useful materials. These “natural” materials often have a lower carbon footprint than fully synthetic materials (e.g., concrete or fiberglass) and can, in principle, be biodegraded and / or repurposed after use in an article. However, such articles formed using natural materials often have inferior properties compared to fully synthetic alternatives. To address such inferior properties (e.g., mechanical strength or thermal conductivity), natural materials might be blended with artificial materials to afford “hybrid materials”. As with purely synthetic materials, hybrid materials often cannot be recycled or might require energy-intensive processes to be recycled.

[0010] Wool, such as sheep wool, is an abundant ‘waste’ material and a potential resource for producing useful articles. For example, it has a microstructure that confers favourable (low) thermal conductivity, making it an ideal candidate for thermal insulation materials. While it is known to use wool for insulation, the processing of wool to produce insulation materials (e.g., insulation panels) chemically alters the wool, degrading its mechanical and thermal conductivity properties. For example, ITGE20120029A1 describes methods of making wool insulation panels, but the produced panels have poor mechanical strength and / or unfavourable thermal conductivity. 008880825

[0011] 2

[0012] Thus, there is a need for sustainable, natural materials which have comparable or improved properties compared to known artificial or hybrid materials. There is also a need for improved methods of making said natural materials.

[0013] The present invention has been devised in the light of the above considerations.

[0014] Summary of the Invention

[0015] At its broadest, the present invention relates to materials, for example materials that comprise natural fibres (i.e., fibres of biological origin, such as wool), and methods of making said materials.

[0016] The present inventors have found that certain manufacturing methods can afford articles for addressing the aforementioned problems. That is, they have developed a process for producing articles, the methods utilising natural waste materials such as plant or animal fibres. Such methods can afford articles having, for example, favourable thermal conductivity for insulation and / or favourable mechanical properties. In other words, such methods can afford materials having an advantageous balance of properties. Such articles may also have a reduced carbon footprint compared to known materials and are believed to be suitable for recycling and / or repurposing after use.

[0017] In a first aspect, the invention provides a method for producing a cured wool article, the method comprising, generally:

[0018] (a) providing wool fibres;

[0019] (b) performing a hydrolysis reaction on the wool fibres to provide degraded wool fibres;

[0020] (c) mixing the degraded wool fibres with additional fibres to provide a pre-cured wool mixture, wherein the additional fibres are chopped fibres; and

[0021] (d) curing the pre-cured wool mixture to afford a cured wool article.

[0022] Wool fibres may refer to fibres obtained from sheep, goats, camels, rabbits, llamas, alpacas, oxen, vicuna, or yaks.

[0023] As used herein, “chopped fibres” refers to a clump of or clumps of fibres that are or have been chopped, for example cut, to a particular size (‘clump size’, referring to dimensions of a clump, such as a height, width, and / or length), for example to a particular length (‘clump length’, being the longest end-to-end distance of a clump of wool). That is, chopped fibres may be formed from unchopped fibres by cutting (for example from carded wool fibres, which may be commercially available), for example such that a clump or clumps have a largest end-to-end dimension according to a predetermined clump length. When the additional fibres are wool fibres, the term “chopped fibres” may thereby refer to a clump of or a plurality of clumps of wool fibres.

[0024] As such, in some embodiments the method may comprise (i) providing additional fibres; and (ii) cutting the additional fibres to provide chopped fibres having a predetermined clump size. In other words, the formation of chopped fibres does not require aligning the fibres and cutting the fibres to a uniform fibre length. A wool clump or a plurality of wool clumps may thereby be referred to as chopped fibres. The 008880825

[0025] 3 provision of chopped fibres in step (ii) may comprise cutting the additional fibres to afford a plurality of clumps.

[0026] As described above, a clump size may refer to a clump dimension, such as a clump length (being the longest end-to-end distance of a clump of wool). When the chopped fibres comprise a plurality of clumps, a clump length may refer to the arithmetic mean of clump lengths for the plurality of clumps (an average clump length). As such, when the chopped fibres comprise a plurality of clumps, the term clump length may be replaceable with the term ‘average clump length’. A clump length may be determined by measuring an end-to-end distance of a clump of chopped fibres.

[0027] An example of additional fibres is wool fibres. When the additional fibres are wool fibres, and the additional fibres are chopped fibres, the additional fibres may be referred to as chopped wool fibres. Accordingly, chopped wool fibres may refer to a clump of or plurality of clumps of wool fibres (‘wool fibre clumps’).

[0028] In some embodiments, the chopped fibres may have a clump length of between around 1 cm or more and 5 cm or less. In some embodiments, the chopped fibres may have a clump length of around 5 cm or less, for example a clump length of 1 cm or less. By contrast, unchopped fibres have a length dimension of around 15 cm or more.

[0029] The term “hydrolysis reaction” refers to a reaction for degrading wool fibres by hydrolysis. It is known that wool fibres comprise keratin polypeptides. Keratin polypeptides comprise amide bonds which may be hydrolysed under some conditions, for example in the presence a base or in the presence of an enzyme.

[0030] Herein, “degraded wool fibres” refers to wool fibres which have been subjected to a hydrolysis reaction. That is, degraded wool fibres comprise partially hydrolysed keratin polypeptides, meaning that some amide bonds are not hydrolysed during the hydrolysis reaction. The extent of polypeptide degradation can be adjusted according to hydrolysis reaction conditions, for example by controlling reaction temperature, pH, and reaction duration, and according to the reagent(s) selected for the hydrolysis reaction.

[0031] The term “wool mixture” is used to refer to a combination of additional (‘untreated’) fibres (i.e., ‘nondegraded’ wool fibres that have not been subjected to a hydrolysis reaction) and degraded wool fibres (i.e., wool fibres that have been subjected to a hydrolysis reaction).

[0032] Herein, “curing” refers to a process of heating a pre-cured wool mixture. Without wishing to be bound by theory, it is believed that heating of the pre-cured wool mixture may facilitate physical and / or chemical binding between degraded wool fibres and other degraded wool fibres or additional fibres. It is also understood that curing causes dehydration of the pre-cured wool mixture. By curing a pre-cured wool mixture, a cured (wool) article is produced.

[0033] The term “cured wool article” is used to refer to a composite product comprising a mixture of chopped fibres (additional fibres that are chopped fibres) and degraded wool fibres that has been cured. A cured wool article herein may otherwise be referred to as a cured article. 008880825

[0034] 4

[0035] Surprisingly, the inventors have found that the present methods afford cured wool articles having acceptable and even improved mechanical properties and / or insulation properties compared to known cured wool articles produced by different methods. For example, cured wool articles of the present invention can have an improved balance of compressive strength and thermal conductivity (insulating property) compared to other wool articles of a similar density. That is, looked at differently, for a given thermal conductivity they can be lower density (and hence easier to handle).

[0036] As used herein, the term “compressive strength” refers to a compressive strength at 10% strain.

[0037] In some embodiments, the pre-cured wool mixture has a predetermined weight fraction of degraded wool fibres, wherein the weight fraction of degraded wool fibres is determined according to the methods of the description, as defined herein below. In some embodiments, the (predetermined) weight fraction may be from around 0.05 to around 0.75.

[0038] “predetermined weight fraction of degraded wool fibres” refers to a weight fraction or ratio of degraded wool fibres of the pre-cured wool mixture. A “predetermined weight fraction of degraded wool fibres” equivalently refers to a weight fraction or ratio of degraded wool fibres according to Equation 1 : weight of wool fibres provided in step (a) (Equation 1) weight fraction of degraded wool fibres = - - - - - — — - - — - total weight of fibres provided

[0039] In Equation 1 , total weight of fibres provided is interchangeable with “weight of wool fibres provided in step (a) + weight of additional fibres”. The “weight of additional chopped fibres” is interchangeable with “the weight of fibres provided in step (c)”.

[0040] In some embodiments, the additional fibres are wool fibres. Alternatively, in some embodiments, the additional fibres are natural fibres other than wool fibres, as defined herein. Preferably, the additional fibres are wool fibres. As such, when the additional wool fibres are wool fibres (which are “chopped wool fibres” because all additional fibres are chopped fibres), the total weight of fibres provided is equal to the sum of the weight of wool fibres provided in step (a) and the additional chopped wool fibres provided in step (c).

[0041] In some embodiments, the hydrolysis reaction may be performed until a percentage concentration of soluble keratin degradation products dissolved in the hydrolysis reaction solution is between from around 20% to around 75%, wherein the percentage concentration of soluble keratin degradation products is measured according to the methods of the description. In some embodiments, the hydrolysis reaction may be performed until a percentage concentration of soluble keratin degradation products is between from around 35% to around 55%.

[0042] In a second aspect, the invention relates to an article produced according to a method of the first aspect (i.e., a ‘cured wool article’). A cured wool article produced by the method of the first aspect may have an improved balance of compressive strength and thermal conductivity compared to known wool articles. In other words, articles according to the second aspect may have improved compressive strength and / or thermal conductivity (increased insulating ability) at a specified article density, compared to known wool articles. 008880825

[0043] 5

[0044] Known cured wool articles, that are generally produced by methods comprising a wool fibre hydrolysis step, have inferior mechanical strength and thermal conductivity. This includes articles produced according to methods of ITGE20120029A1. Without wishing to be bound by theory, this is at least because hydrolysis damages the wicked microstructure of wool, reducing its ability to trap air (increasing thermal conductivity and reducing insulating ability). By contrast, articles produced by the methods of the present invention possess a wicked microstructure having less damage, in addition to inter-fibre binding. In turn, articles produced by methods of the present invention have an improved balance of thermal conductivity and mechanical strength.

[0045] In some embodiments, cured wool articles have a density of for example 200 kg / m3or less, for example 180 kg / m3or less, for example 170 kg / m3or less, for example 160 kg / m3or less, for example 150 kg / m3or less, for example 140 kg / m3or less, for example 130 kg / m3or less, for example 120 kg / m3or less, for example 110 kg / m3or less, for example 100 kg / m3or less, for example 90 kg / m3or less, for example 80 kg / m3or less, or for example 70 kg / m3or less.

[0046] In a third aspect, the invention relates to use of an article according to the second aspect. Use of an article according to the second aspect may comprise installing a cured wool article in or on a product or building.

[0047] The invention includes the combination of the aspects and preferred features described except where such a combination is clearly impermissible or expressly avoided.

[0048] 008880825

[0049] 6

[0050] Detailed Description of the Invention

[0051] Aspects and embodiments of the present invention will now be discussed. Further aspects and embodiments will be apparent to those skilled in the art. All documents mentioned in this text are incorporated herein by reference.

[0052] Providing wool fibres

[0053] Wool fibres are provided for performing the methods of the invention. “Providing wool fibres” includes the provision of unchopped or chopped wool fibres.

[0054] In some embodiments, the wool fibres may be obtained by shearing mammals such as sheep, goats, camels, rabbits, llamas, alpacas, oxen, vicuna, or yaks.

[0055] In some embodiments, the wool fibres may be carded wool fibres, plucked wool fibres, and / or scoured wool fibres as defined herein below.

[0056] “Wool fibres” for the step of providing wool fibres does not include degraded wool fibres.

[0057] Hydrolysis reaction

[0058] Methods for producing a cured wool article according to the present invention comprise a step of performing a hydrolysis reaction. As used herein, the term “hydrolysis reaction” refers to a reaction for degrading wool fibres by hydrolysis.

[0059] It is known that wool fibres comprise keratin polypeptides. Keratin polypeptides comprise C-N amide bonds which may be hydrolysed under some conditions, for example in the presence a base or in the presence of an enzyme. Keratin (polypeptide) degradation can produce shorter-chain peptides, which may in turn produce ‘soluble keratin degradation products’, such as oligopeptides, amino acids, and derivatives thereof which are soluble in a hydrolysis reaction solution.

[0060] In some embodiments, a hydrolysis reaction may be performed by contacting wool fibres with a hydrolysis reaction solution, as defined below. In some embodiments, contacting wool fibres with a hydrolysis reaction solution may comprise immersing the wool fibres in the hydrolysis reaction solution. In some embodiments, contacting wool fibres with a hydrolysis reaction solution may comprise spraying or otherwise coating the wool fibres with a hydrolysis reaction solution.

[0061] In some embodiments, the hydrolysis reaction is a base-mediated hydrolysis reaction, meaning that the hydrolysis reaction solution comprises a base. A suitable base may be for example NaOH or KOH, and other suitable bases are defined hereinbelow according to formula (I).

[0062] In some embodiments, the hydrolysis reaction is an enzyme-mediated hydrolysis reaction, meaning that the hydrolysis reaction solution comprises an enzyme for hydrolysing keratin. In some embodiments, the enzyme may be a keratinase. Alternatively, an enzyme may be one selected from the group consisting of a protease, papain, and a collagenase.

[0063] Alternatively, in some embodiments, the hydrolysis reaction may be a steam hydrolysis reaction. Methods for performing steam hydrolysis are known in the art and can be used accordingly. For example, steam 008880825

[0064] 7 hydrolysis may comprise contacting wool fibres with steam. A steam hydrolysis reaction may be performed at a pressure above atmospheric pressure.

[0065] A reaction temperature is not particularly limited and can be adjusted accordingly. When the hydrolysis reaction is a base-mediated hydrolysis reaction, the reaction may be performed at a reaction temperature of between around 40 °C or more and around 250 °C or less, for example between around 50 °C or more and around 220 °C or less, for example between around 50 °C or more and around 180 °C or less, for example between around 50 °C or more and around 120 °C or less, for example between around 50 °C or more and around 80 °C or less, for example between around 50 °C or more and around 60 °C or less, or for example around 60 °C.

[0066] When the hydrolysis is an enzyme-mediated hydrolysis reaction, the reaction may be performed at a reaction temperature of between around 10 °C or more and 60 °C or less, for example between around 20 °C or more and around 45 °C or less, for example between around 25 °C or more and around 35 °C or less, for example around 25 °C.

[0067] A hydrolysis reaction duration is not particularly limited and can be adjusted accordingly.

[0068] When the hydrolysis reaction is a base-mediated hydrolysis reaction, the reaction may be performed for a reaction duration of around 10 minutes, for example around 20 minutes, for example around 30 minutes, for example around 45 minutes, for example around 60 minutes, for example around 90 minutes, for example around 120 minutes, for example around 180 minutes, for example around 240 minutes, or for example around 300 minutes.

[0069] When the hydrolysis is an enzyme-mediated hydrolysis reaction, the reaction may be performed at a reaction duration of around 60 minutes, for example around 120 minutes, for example around 180 minutes, for example around 240 minutes, for example around 300 minutes, for example around 500 minutes, for example around 1000 minutes.

[0070] A hydrolysis reaction concentration means a concentration of base or enzyme as applicable. In other words, a hydrolysis reaction concentration refers to a base concentration or an enzyme concentration in the hydrolysis reaction solution. Alternatively, a hydrolysis reaction concentration may be called a hydrolysis reaction solution concentration. Hydrolysis reaction concentration is not particularly limited and can be adjusted accordingly.

[0071] When the hydrolysis reaction is a base-mediated hydrolysis reaction, the hydrolysis reaction concentration (corresponding to a base concentration or reaction solution concentration) may be between 5 g / L or more and 100 g / L or less, for example around 5 g / L or more and 75 g / L or less, for example around 5 g / L or more and around 50 g / L or less, for example around 5 g / L or more and around 40 g / L or less, for example around 5 g / L or more and around 30 g / L or less, for example around 10 g / L or more and around 20 g / L or less. Preferably, when the hydrolysis reaction is a base-mediated hydrolysis reaction, the hydrolysis reaction concentration is between around 10 g / L or more and 20 g / L or less. 008880825

[0072] 8

[0073] When the hydrolysis reaction is a base-mediated hydrolysis reaction, the reaction pH (corresponding to a hydrolysis reaction solution pH) may be 9 or more, preferably 10 or more, more preferably 11 or more, even more preferably 12 or more, most preferably 13 or more.

[0074] When the hydrolysis is an enzyme-mediated hydrolysis reaction, the reaction concentration (which refers to an amount of enzyme in solution) may be between 0.05 w / v% or more and 0.2 w / v% or less, for example around 0.1 w / v%. A w / v% refers to an amount of enzyme defined in grams per Litre of solution.

[0075] Each of the above-defined hydrolysis reaction temperature, reaction duration, reaction pH, and hydrolysis reaction solution concentration can be adjusted for controlling an extent of hydrolysis and possible crosslinking and / or binding of keratin fibres, thereby controlling an extent of keratin and wool degradation (which is defined further, below). For example, increasing each of hydrolysis reaction solution concentration (e.g., base concentration), hydrolysis reaction duration, and hydrolysis reaction temperature is understood to increase an amount of or extent of keratin degradation, may increase an amount or extent of inter-fibre binding and / or cross-linking.

[0076] In some embodiments, the hydrolysis reaction may comprise stirring, optionally mechanical stirring. Mechanical stirring may be performed with a mechanical stirrer.

[0077] In some embodiments, the hydrolysis reaction utilises a recycled keratin solution as defined below, instead of a hydrolysis reaction solution. That is, in a method for producing a cured wool article according to the present invention, any keratin solution (i.e., used or spent hydrolysis reaction solution) may be recycled and used in a subsequent method for producing a cured wool article. In such embodiments, it is believed that a carbon footprint of the method is reduced as compared to using a hydrolysis reaction solution. Such methods for producing a cured wool article may be referred to as circular methods.

[0078] Mixing

[0079] After the hydrolysis reaction, degraded wool fibres are mixed with additional fibres, for example additional wool fibres, to provide a pre-cured wool mixture. “Additional fibres” means fibres that have not been subjected to the hydrolysis reaction solution. The additional fibres are chopped fibres as defined herein.

[0080] In some embodiments, when the additional fibres are wool fibres, the additional wool fibres may be chopped wool fibres or scoured wool fibres. Preferably the additional wool fibres are chopped wool fibres. More preferably, the additional wool fibres are chopped and scoured wool fibres.

[0081] Mixing may comprise adding degraded wool fibres to additional fibres or adding additional fibres to degraded wool fibres. One component may be added to the other component in a stepwise manner with continuous mixing, or in a concerted matter prior to mixing.

[0082] An amount of degraded wool fibres and / or additional fibres may be increased until a weight fraction of degraded wool fibres is equal to the predetermined weight fraction of degraded wool fibres as defined herein. Additionally, an amount of degraded wool fibres and / or additional fibres may be increased until the pre-cured mixture is equal to a predetermined mass.

[0083] A weight fraction of degraded wool fibres may be as defined herein, below or above. 008880825

[0084] 9

[0085] Mixing may be performed by mechanically stirring degraded wool fibres with additional fibres. This is understood to homogenise the components, which may afford cured wool articles having uniform properties (such as uniform or isotropic mechanical properties throughout the article). It is understood that when the additional fibres are chopped fibres, a pre-cured mixture can have an increased homogeneity, which can afford cured wool articles having an improved uniformity of properties, thereby improving an overall mechanical strength and / or insulating ability across the article and an overall balance of said properties throughout the article.

[0086] A mixing duration and mixing rate (e.g., stirring rate) is not particularly limited, and may be adjusted until the components are mixed to an acceptable level. For example, a mixing duration may be between 2 minute or more and 5 minutes or less, optionally 2 minutes. For example, a mixing rate may be around 60 revolutions per minute (rpm).

[0087] As described herein below, in some embodiments, the degraded wool fibres may be mixed with additional natural fibres other than wool fibres. In such embodiments, mixing may therefore instead comprise adding degraded wool fibres to additional natural fibres other than wool fibres or adding additional natural fibres other than wool fibres to degraded wool fibres. If additional natural fibres other than wool fibres are mixed with degraded wool fibres, references herein to additional wool fibres may instead be applied mutatis mutandis to the additional natural fibres other than wool fibres.

[0088] Curing

[0089] “Curing” refers to a process of heating a pre-cured wool mixture. By curing a pre-cured wool mixture, a cured (wool) article is produced. Many such curing methods are known in the art and may be used for the curing step of the present invention. For example, curing may comprise heating a pre-cured mixture in an oven, at a predetermined curing temperature and for a predetermined curing time.

[0090] Without wishing to be bound by theory, it is understood that heating of the pre-cured wool mixture can facilitate physical and or chemical binding between degraded wool fibres and other degraded wool fibres or additional fibres. It is also understood that curing causes dehydration of the pre-cured wool mixture.

[0091] A curing temperature is not particularly limited and may be adjusted according to a predetermined curing duration. When a curing temperature is increased, a curing duration may be reduced. For example, a curing temperature may be between around 50 °C or more and around 220 °C or less, for example between around 50 °C or more and around 180 °C or less, for example, between around 60 °C or more and around 180 °C or less. In some embodiments, a curing temperature is around 60 °C. In some embodiments, a curing temperature is around 180 °C.

[0092] A curing duration is not particularly limited and may be adjusted according to a predetermined curing temperature. When a curing duration is increased, a curing temperature may be reduced. For example, a curing duration may be around 24 hours or less, for example around 20 hours or less, for example around 18 hours or less, for example around 16 hours or less, for example around 12 hours or less, for example around 8 hours or less, for example around 4 hours or less, for example around 3 hours or less, or for example around 2 hours or less. 008880825

[0093] 10

[0094] When a curing temperature is around 180 °C, a curing duration may be around 3 hours. When a curing temperature is around 60 °C, a curing duration may be around 16 hours.

[0095] A curing temperature and curing duration may also be adjusted according to a target size of a cured wool article. A target size of a cured wool article may be adjusted by increasing an amount of fibres provided in methods for producing cured wool article. For example, a curing duration and / or temperature may be increased if an amount of fibres wool fibres provided for a hydrolysis reaction is over 500 g.

[0096] Curing may be performed in a mould of a predetermined size and / or shape, and a cured wool article may be removed from the mould after curing.

[0097] Scouring (step a1)

[0098] In some embodiments, the method the method further comprises a step (a1), wherein step (a1) comprises scouring wool after step (a) and before step (b). Alternatively, in some embodiments, the wool provided in step (a) is scoured wool.

[0099] “Scouring” refers to a process for removing contaminants such as skin, dirt, and other solid matter impurities from wool materials. Methods for scouring are known in the art and are not particularly limited. Scouring may for example refer to mechanical scouring, such as batch scouring or continuous scouring, to solvent scouring, to enzymatic scouring, or to ultrasonic scouring.

[0100] Blending (step b1)

[0101] In some embodiments, the method further comprises a step (b1), wherein step (b1) comprises blending the degraded wool fibres, wherein step (b1) is performed after step (b) and before step (c). That is, the method for producing a cured wool article may further comprise blending the degraded wool fibres produced from the hydrolysis reaction, before a step of mixing the degraded wool fibres with additional (chopped) fibres. Without wishing to be bound by theory, it is believed that blending the degraded wool fibres permits a more homogeneous mixture in the mixing step, which may improve rigidity in cured wool articles.

[0102] Methods for blending wool are well known in the art and may comprise rotary blending or another type of blending.

[0103] Blending may be performed at a blending speed of around 100 rpm or more, for example 300 rpm or more, for example around 600 rpm or more, for example around 900 rpm or more, for example 1200 rpm or more, for example around 1600 rpm or more, or for example around 2000 rpm or more. A blending speed means a rate of revolution of a blending blade or blending blades.

[0104] A blending duration is not particularly limited and may be adjusted according to a predetermined blending speed. That is, when blending speed is increased, a blending duration may be reduced. A blending duration may be around 30 seconds or more, for example around 60 seconds or more, or for example 120 seconds or more. 008880825

[0105] 11

[0106] Pressing (step c1)

[0107] In some embodiments, the method further comprises a step (c1), wherein step (c1) comprises pressing the pre-cured wool mixture, wherein step (c1) is performed after step (c) and before step (d). Pressing means mechanical pressing and is well-known in the art. Means for pressing are not particularly limited, and may comprise hydraulic presses, screw presses, or punch presses.

[0108] Without wishing to be bound by theory, pressing is believed to reduce a water content of compositions, for example compositions comprising degraded wool fibres and additional wool fibres. That is, pressing expels excess water from such compositions. Pressing may also increase cured wool article rigidity by increasing inter-fibre binding, thereby improving an ability of cured wool articles to maintain their shape under stress. Yet further, pressing may permit reduced curing durations and / or temperatures.

[0109] Pressing may be performed until an amount of effluent runoff decreases to an acceptable level or is no longer observed.

[0110] A pressure for pressing is not particularly limited and may be adjusted to fine-tune a density of a cured wool article. It is believed that increasing a pressure during a pressing step can increase a density of a cured wool article. A pressure during a pressing step may be for example 300 kPa or less, for example 250 kPa or less, for example 200 kPa or less, for example 150 kPa or less, for example 100 kPa or less. In some embodiments, a pressure during pressing may between 80 kPa or more and 120 kPa or less, for example 90 kPa or more and 110 kPa or less, for example 90 kPa or more and 100 kPa or less.

[0111] Wool fibres

[0112] The term “wool fibres” refers to textile fibres obtained from sheep and other mammals, and not to inorganic materials such as mineral wool or glass wool. Wool fibres can be obtained by shearing mammals such as sheep, goats, camels, rabbits, llamas, alpacas, oxen, vicuna, and yaks.

[0113] “Wool fibres” according to the invention may be chopped wool fibres or unchopped wool fibres. “Chopped wool fibres” are wool fibres that have been chopped, for example by cutting, to have a particular clump length. Chopped wool fibres may have a clump length of around 1 cm, around 2 cm, around 3 cm, around 4 cm, around 5 cm, or around 7.5 cm. “Unchopped” wool fibres are known generally to have a length dimension of around 15 cm or more. In some embodiments, chopped wool fibres may have a clump length of around 1 cm or more and around 7.5 cm or less, for example a clump length of around 1 cm or more and around 5 cm or less, for example a clump length of around 1 cm or more and around 4 cm or less, for example a clump length of around 1 cm or more and around 3 cm or less, or for example a clump length of around 1 or more and around 2 cm or less.

[0114] Chopped fibres, in particular chopped wool fibres, can be processed according to the methods of the invention with more ease than unchopped (wool) fibres. For example, a mixing step may afford a precured mixture having an increased homogeneity when chopped fibres are used. Additionally, as exemplified below, when the additional fibres are chopped fibres, cured wool articles having an improved balance of density and compressive strength (corresponding to an improved balance of thermal 008880825

[0115] 12 conductivity and compressive strength) can be achieved. That is, when additional fibres are unchopped fibres, compressive strength is inferior for cured wool articles of a given density.

[0116] In some embodiments, the wool fibres provided are carded wool fibres. “Carded wool” refers to wool processed by carding. Methods for carding wool are known in the art and are not particularly limited. Carding may be performed to provide carded wool fibres. For example, carded wool may refer to wool produced by drum carding or pin carding.

[0117] In some embodiments, the wool fibres are plucked wool fibres. “Plucked wool” refers to wool which is sourced from animal skin, for example by known plucking processes. Methods for plucking are known in the art and are not particularly limited.

[0118] In some embodiments, the wool fibres are scoured wool fibres. “Scoured wool” refers to wool processed by known scouring methods, to remove contaminants such as skin, dirt, and other solid matter impurities. Methods for scouring are known in the art and are not particularly limited. Scouring may for example refer to mechanical scouring, such as batch scouring or continuous scouring, to solvent scouring, to enzymatic scouring, or to ultrasonic scouring. Scouring is also believed to remove lanolin, which is known to coat some wool fibres. Scouring, or providing scoured wool fibres is believed to reduce a risk of lowering an efficiency of the hydrolysis reaction, and may negatively impact a balance of mechanical strength and insulating ability of cured wool articles.

[0119] “Degraded wool fibres” described herein are wool fibres which are produced according to a hydrolysis reaction of the method of the present invention. That is, degraded wool fibres are fibres which may be produced by contacting wool fibres with a hydrolysis reaction solution, for example a solution comprising a base. Degraded wool fibres are insoluble in a hydrolysis reaction solution. Bases for producing degraded wool fibres may include but are not limited to alkali metal hydroxides or alkaline earth metal hydroxides, such as NaOH or KOH. In some embodiments, the degraded wool fibres are subjected to blending.

[0120] After blending, such fibres may also be referred to as degraded wool fibres. Alternatively, such fibres may be referred to as blended wool fibres. After mixing degraded (and optionally blended) wool fibres with additional fibres, the resulting mixture comprising may be referred to as a wool mixture, wool fibremixture, or pre-cured wool mixture, which may be subjected to pressing.

[0121] Keratin and degradation products thereof

[0122] Keratins are epidermal fibrous proteins produced by many mammals. The term “keratin” may be used to refer to a plurality of different keratin fibres (i.e., keratins). Keratin is known as a primary component of wool fibres, in addition to mammalian hair and nails.

[0123] Keratin, and in turn wool, comprises conjugated amino acids. Such conjugated acids comprise amide C- N bonds which may be reactive to hydrolysis in the presence of a hydrolysis reaction solution.

[0124] During a hydrolysis reaction, keratin amino acid chains may be cleaved at conjugated amide C-N bonds, thereby forming insoluble “degraded” keratin fibres of a shorter chain length, having terminal carboxylic 008880825

[0125] 13 acid moieties (-CO2H) and / or terminal primary or secondary amine moieties. Degraded keratin fibres may correspond to a degraded wool fibres. Degraded keratin fibres, and for example degraded wool fibre, is understood to have a fibrous structure. Further degradation of (insoluble) degraded keratin fibres are believed to produce other degradation products (for example, single amino acids or oligomeric amino acid structures), which may be soluble in the hydrolysis reaction solution and thus may be referred to as ‘soluble keratin degradation products’. Such soluble keratin degradation products degradation products may not have a fibrous structure due to their size (e.g., chain length). As defined below, the formation of soluble keratin degradation products (SKDP) may be measured to determine an extent of keratin degradation, for monitoring a hydrolysis reaction.

[0126] During a hydrolysis reaction, degraded keratin fibres may in turn react with other (non-degraded) keratin fibres and / or degraded keratin fibres, forming a cross-linked matrix of amino acid chains. It is understood in the art that hydrolysis of wool keratin damages its wicked microstructure, thereby reducing insulating properties of the wool of a macroscopic level.

[0127] The extent of hydrolysis and cross-linking may be controlled by adjusting reaction conditions, such as a reaction duration, a reaction component concentration (for example, base concentration), and / or a reaction temperature. For example, increasing each of hydrolysis reaction solution concentration, hydrolysis reaction duration, and hydrolysis reaction temperature is understood to increase an amount of or extent of keratin degradation, and may increase an amount or extent of cross-linking.

[0128] A standardised ‘extent of keratin degradation’ can be determined and may be used to monitor a hydrolysis reaction, for example to determine when to terminate the hydrolysis reaction. Specifically, an extent of keratin degradation can be determined at a reaction timepoint by measuring an amount of soluble keratin degradation products dissolved in the hydrolysis reaction solution and calculating a corresponding percentage concentration of soluble keratin degradation products dissolved in the reaction solution at said timepoint ([SKDP]j, as defined below according to Equation (2)).

[0129] As mentioned above, increasing a hydrolysis reaction duration may increase an amount of keratin degradation and is understood to increase an amount of soluble keratin degradation products dissolved in the hydrolysis reaction solution. At the start of a hydrolysis reaction with ‘fresh’ reagents, zero keratin is degraded, so an amount of soluble keratin degradation products dissolved in the hydrolysis reaction solution is zero. Correspondingly, a percentage concentration of soluble keratin degradation products dissolved in the hydrolysis reaction solution is 0%.

[0130] At complete keratin degradation, substantially all possible keratin is degraded to soluble keratin degradation products and a percentage concentration of soluble keratin degradation products dissolved in the hydrolysis reaction solution is 100%.

[0131] A standardised extent of keratin degradation can thereby be measured as follows, for a predetermined set of reaction conditions (e.g., for a particular scale of reaction and a particular concentration of a predetermined base or enzyme, and for a predetermined reaction temperature). 008880825

[0132] 14

[0133] At the start of a hydrolysis reaction, an initial aliquot may be taken from the hydrolysis reaction solution (e.g., 5 mL). The aliquot may be dried (by evaporating any solvents, such as water) to leave only residual solids. An initial mass of residual solids may be gravimetrically measured to define a reference mass value. The reference mass value corresponds to a mass of residual solids when the hydrolysis reaction solution contains 0% soluble keratin degradation products. Additional aliquots may be taken at different timepoints during the hydrolysis reaction, and a mass of residual solids of each aliquot can be gravimetrically measured for each respective timepoint. As the hydrolysis reaction progresses and the extent of keratin degradation increases, a mass of residual solids in each aliquot correspondingly increases. In other words, when an extent of keratin degradation increases, the mass of residual solids from an aliquot increases because the aliquot comprises elevated amounts of soluble keratin degradation products (for example compared to the reference mass value or a mass of residual solids determined for a previous timepoint). When all possible keratin is degraded, a concentration of soluble keratin degradation products reaches a maximum value, which can be measured by taking a final aliquot, drying the aliquot, gravimetrically measuring a final mass of residual solids, and subtracting the reference mass value. The mass difference corresponds to a concentration of soluble keratin degradation products at 100% relative concentration of soluble keratin degradation products.

[0134] A percentage concentration of soluble keratin degradation products (SKDP) at a timepoint t, corresponding to an extent of keratin degradation at timepoint t, may thus be determined according to the following Equation (2), for a predetermined set of reaction conditions:

[0135] (Equation 2 where t = reaction timepoint (amount of time elapsed for a hydrolysis reaction); mt = mass of residual solids at timepoint t mo = mass of residual solids at t = 0 (the start of the hydrolysis reaction); mCompietion = mass of residual solids at completion (i.e., when the keratin is as degraded as possible into soluble keratin degradation products; that is, when the reaction has progressed to completion); and

[0136] [SKDP]t = percentage concentration of soluble keratin degradation product at timepoint t.

[0137] In some embodiments, a hydrolysis reaction may be performed until a percentage concentration of soluble keratin degradation products dissolved in the hydrolysis reaction solution reaches or is above a lower threshold value. For example, a hydrolysis reaction may be performed until a percentage concentration of soluble keratin degradation products is around 20% or more, for example around 25% or more for example around 30% or more, for example around 35% or more, for example 40% or more, for example 45% or more, for example 50% or more, or for example 55% or more. When a concentration of soluble keratin degradation products is around 20% or more, cured articles can exhibit an improved balance of mechanical strength and given density, compared to known articles, and may further exhibit favourable thermal conductivity properties. When a concentration of soluble keratin degradation products is under 20%, an extent of degradation may be insufficient and cured articles may exhibit unacceptable 008880825

[0138] 15 mechanical strength. Such articles may also exhibit unacceptable thermal conductivity properties. Without wishing to be bound by theory, this may be due to poor intra-fibre binding and / or cross-linking. Preferably, a hydrolysis reaction is performed until a concentration of soluble keratin degradation products is around 35% or more.

[0139] In some embodiments, a hydrolysis reaction may be performed only until a percentage concentration of soluble keratin degradation products dissolved in the hydrolysis reaction solution reaches or is below an upper threshold value. For example, a hydrolysis reaction may be performed until a percentage concentration of soluble keratin degradation products is around 75% or less, for example around 70% or less, for example around 65% or less, for example around 60% or less, for example around 55% or less, for example around 50% or less, for example around 45% or less, for example around 40% or less, for example around 35% or less, for example around 30% or less, or for example around 25% or less. When a concentration of soluble keratin degradation products is around 75% or less, cured articles can exhibit an improved balance of mechanical strength and given density, compared to known articles, and may further exhibit favourable thermal conductivity properties. When a concentration of soluble keratin degradation products is above 75%, over-degradation of the fibres can occur, and cured articles may exhibit unacceptable mechanical strength, which may be for example due to destruction of fibrous microstructures. Such articles may also exhibit unacceptable thermal conductivity properties. Preferably, a hydrolysis reaction is performed until percentage concentration of soluble keratin degradation products is around 55% or less.

[0140] In some embodiments, a hydrolysis reaction may be performed until a percentage concentration of soluble keratin degradation products (dissolved in the hydrolysis reaction solution) is between from around 20% or more to around 75% or less, for example from around 20% or more to around 70% or less, for example from around 20% or more to around 60% or less, for example from around 25% or more to around 60% or less, for example from around 30% or more to around 60% or less, for example from around 35% or more to around 60% or less, or for example from around 35% or more to around 55% or less. Preferably, a hydrolysis reaction is performed until percentage concentration of soluble keratin degradation products is from around 30% or more to around 70% or less, and more preferably a hydrolysis reaction is performed until a percentage concentration of soluble keratin degradation products is from around 35% or more to around 55% or less.

[0141] Keratin solution

[0142] During a hydrolysis reaction, keratin fibres are hydrolysed by the hydrolysis reaction solution to form (insoluble) degraded keratin fibres and soluble keratin degradation products. Following the hydrolysis reaction, the hydrolysis reaction solution may be referred to as a “keratin solution”. A keratin solution is used to mean a solution comprising hydrolysis reaction solution components, for example a base or enzyme, in addition to soluble keratin degradation products.

[0143] Keratin solution does not refer to degraded wool fibres, which are insoluble and thus may be separated from the keratin solution following the hydrolysis reaction, for example by filtering, optionally with a sieve. 008880825

[0144] 16

[0145] Accordingly, in some embodiments, step (b) may comprise separating degraded wool fibres from a keratin solution after performing the hydrolysis reaction.

[0146] In some embodiments, a keratin solution is used instead of a hydrolysis reaction solution. That is, a keratin solution may be recycled and used for hydrolysis of wool fibres.

[0147] In some embodiments, when a keratin solution is used instead of a hydrolysis reaction solution, a percentage concentration of soluble keratin degradation products may be used to monitor a hydrolysis reaction. In such embodiments, an initial mass of residual solids mo can be measured at the start of the hydrolysis reaction and may comprise soluble keratin degradation products. In such embodiments, SKDP is present at the start of the reaction because the keratin solution is ‘recycled’ (e.g., from a previous hydrolysis reaction).

[0148] Wool mixture

[0149] The term “wool mixture” is used to refer to a combination of ‘untreated’ fibres (i.e., additional fibres that have not been subjected to a hydrolysis reaction) and degraded wool fibres (i.e., wool fibres that have been subjected to a hydrolysis reaction). Wool mixture is also referred to as a “pre-cured wool mixture”, indicating that said mixture is for curing to afford a cured wool article of the present invention. As described herein, a pre-cured wool mixture may still be described as a pre-cured wool mixture after pressing, if the mixture is pressed.

[0150] A wool mixture has a “predetermined weight fraction of degraded wool fibres”, meaning a weight fraction or ratio of degraded wool fibres in the pre-cured wool mixture. A “predetermined weight fraction of degraded wool fibres” equivalently refers to a weight fraction or ratio of degraded wool fibres according to Equation 1 : weight of wool fibres provided in step (a) (Equation 1) weight fraction of degraded wool fibres = - - - - - — — - - — - total weight of fibres provided

[0151] In Equation 1 , total weight of fibres provided is interchangeable with “weight of fibres provided in step (a) + weight of additional fibres”. The “weight of additional chopped fibres” is interchangeable with “the weight of fibres provided in step (c)”.

[0152] A weight fraction of degraded wool fibres may be for example around 0.05, for example around 0.1 , for example around 0.15, for example around 0.2, for example around 0.25, for example around 0.3, for example around 0.4, for example around 0.5, for example around 0.75.

[0153] A weight fraction of degraded wool fibres may be between from around 0.05 to around 0.75, for example from around 0.2 to around 0.75, for example from around 0.20 to around 0.6, for example from around 0.2 to around 0.5, or for example from around 0.3 to around 0.5. A weight fraction of degraded wool fibres is preferably from around 0.2 to around 0.5, more preferably from around 0.3 to around 0.5.

[0154] In some embodiments, instead of additional wool fibres, the wool mixture comprises degraded wool fibres and additional natural fibres other than wool fibres. Natural fibres other than wool fibres may be selected one or more selected from the group consisting of wood fibres, medium density fibreboard (MDF) fibres, hemp fibres, bamboo fibres, cork fibres, straw fibres, jute fibres, flax fibres, coconut fibres, reed fibres, 008880825

[0155] 17 palm leaf fibres, or kenaf fibres. Natural fibres other than wool fibres may preferably comprise MDF fibres. Without wishing to be bound by theory, it is believed that degraded fibres may also react and / or bind with the aforementioned natural fibres to thereby afford cured, mixed-material articles which may have a tolerable or even favourable balance of mechanical strength and insulating ability.

[0156] Cured wool article

[0157] The term “cured wool article” is used to refer to a composite product comprising a mixture of chopped fibres and degraded wool fibres (pre-cured wool mixture), which is optionally pressed, and is subsequently cured.

[0158] Cured wool articles of the present invention may possess a favourable combination or balance of properties, for example a favourable balance of (low) thermal conductivity (a high insulating ability) and mechanical strength (for example, compressive strength). Without wishing to be bound by theory, it is believed that composite articles of the present invention can achieve such a balance of thermal conductivity and mechanical strength because they comprise a mixture of degraded wool fibres — believed to contribute primarily to mechanical strength of said articles — and ‘non-degraded’ natural fibres — believed to contribute primarily to low thermal conductivity. As shown below, such a favourable balance of properties is achieved by the methods of the present invention, and is not achieved according to known methods. Correspondingly, known cured wool articles do not possess such a favourable balance of properties.

[0159] Cured wool articles of the present invention may be used for construction and may be incorporated into other composite materials.

[0160] Cured wool articles may have predetermined dimensions, such as height, width, and depth. Such dimensions may be determined according to a mould used during the curing process, if a mould is used. Alternatively or additionally, cured wool articles may be cut to predetermined dimensions after a curing step.

[0161] Cured wool articles may have a predetermined shape, such as a panel. Other shapes are envisaged, which may be formed according to a mould shape during curing, if a mould is used, or according to a shaping step after curing, for example be cutting.

[0162] Preferably, cured wool articles are panels.

[0163] A density of the cured wool article (determined according to methods below) may be predetermined depending on an intended use of the cured wool article, for example to meet an acceptable density threshold. In some embodiments, a density of the cured wool article may be for example 350 kg / m3or less, for example 300 kg / m3or less, for example 250 kg / m3or less, for example 200 kg / m3or less, for example 180 kg / m3or less, for example 170 kg / m3or less, for example 160 kg / m3or less, for example 150 kg / m3or less, for example 140 kg / m3or less, for example 130 kg / m3or less, for example 120 kg / m3or less, for example 110 kg / m3or less, for example 100 kg / m3or less, for example 90 kg / m3or less, for example 80 kg / m3or less, or for example 70 kg / m3or less. 008880825

[0164] 18

[0165] A density of cured wool articles can be decreased by increasing an amount of additional fibres in a precured wool mixture. In other words, cured wool article density can be reduced by correspondingly reducing a weight fraction of degraded wool fibres of a pre-cured wool mixture. In general, cured wool articles having a lower density are preferred, with the proviso that cured (wool) articles meet a minimum compressive strength threshold for their intended use. By minimising cured wool article density, article weight can be favourably reduced, and thermal conductivity can be minimised (to maximise corresponding insulating properties). A density of cured wool articles may be fine-tuned by adjusting a pressure during a pressing step. Increasing a pressure during a pressing step may correspondingly increase a density of a cured wool article.

[0166] A compressive strength of cured wool articles can be increased by increasing an amount of degraded wool fibres in a pre-cured wool mixture. In other words, the mechanical strength of a cured wool article can be increased by increasing a weight fraction of degraded wool fibres.

[0167] An acceptable minimum compressive strength of a cured wool article depends on the intended use of said article. A compressive strength of a cured wool article (at 10% strain) may be for example around 2 kPa or more, for example around 3 kPa or more, for example around 4 kPa or more, for example around 5 kPa or more, for example around 6 kPa or more, for example around 7 kPa or more, for example around 8 kPa or more, or for example around 9 kPa or more. In general, cured wool articles having a higher compressive strength are preferred, with the proviso that density (and correspondingly thermal conductivity) is at an acceptable level. Preferably, a compressive strength of a cured wool article (at 10% strain) is 3 kPa or more.

[0168] As such, it is preferable to minimise cured wool article density while maximising compressive strength. For example, a cured wool article may have a density of from around 80 kg / m3to around 180 kg / m3and a compressive strength 3 kPa or more, preferably a density of from around 100 kg / m3to around 160 kg / m3and a compressive strength of 4 kPa or more.

[0169] Hydrolysis reaction solution

[0170] “Hydrolysis reaction solution” is used to mean a solution for performing wool hydrolysis according to the present invention. In turn, a hydrolysis reaction solution is a solution for degrading keratin C-N amide bonds, and for producing degraded wool fibres, and thereby degraded keratin fibres. A hydrolysis reaction solution may be contacted with wool fibres for performing a hydrolysis reaction.

[0171] A hydrolysis reaction solution may comprise a one or more solvents, and one or more solutes. In some embodiments, a hydrolysis reaction solution consists of one or more solvents and one or more solutes.

[0172] Suitable solvents for a hydrolysis reaction are well-known in the art, but may be selected from the group comprising water, methanol, ethanol, iso-propanol, n-propanol, ethyl acetate, acetonitrile, toluene, xylene, and dichloromethane. Preferably, the solvent comprises water.

[0173] In some embodiments, the solvent consists of water. 008880825

[0174] 19

[0175] Solute is used to mean a substance being solubilised or dissolved in the solvent or solvents of the hydrolysis reaction solution.

[0176] In some embodiments, the hydrolysis reaction solution comprises a base and may be used for performing a base-mediated hydrolysis reaction. The term “base” is used to mean a substance such as an alkali metal or alkaline earth metal. Accordingly, in some embodiments, the hydrolysis reaction solution comprises a base defined according to formula (I):

[0177] Xn(OH)mformula (I) wherein in formula (I), X is any one of Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, or Ba, wherein when X is Li, Na, K, Rb, or Cs, n = 1 and m = 1 , and wherein when X is Be, Mg, Ca, Sr, or Ba, n = 2 and m = 2.

[0178] Preferably, the base is selected from NaOH or KOH, and is more preferably NaOH.

[0179] In some embodiments, the hydrolysis reaction solution comprises a combination of two or more bases, for example NaOH and KOH.

[0180] In preferred embodiments, the solvent comprises water and the base is selected from NaOH or KOH.

[0181] When the reaction solution comprises a base, a concentration of base, also called a reaction concentration or base concentration, is not particularly limited and may be between from 5 g / L or more and 100 g / L or less, for example around 5 g / L or more and 75 g / L or less, for example around 5 g / L or more and around 50 g / L or less, for example around 5 g / L or more and around 40 g / L or less, for example around 5 g / L or more and around 30 g / L or less, for example around 10 g / L or more and around 20 g / L or less. When the reaction solution comprises a base, a base concentration is preferably around 10 g / L or more and around 20 g / L or less.

[0182] When the reaction solution comprises a base, a hydrolysis reaction solution pH may be 9 or more, preferably 10 or more, more preferably 11 or more, even more preferably 12 or more, most preferably 13 or more.

[0183] In some embodiments, the solute comprises an enzyme. When the reaction solution comprises an enzyme, an enzyme concentration of enzyme, also called a reaction concentration or enzyme concentration, is not particularly limited and may be 0.05 w / v% or more and 0.2 w / v% or less, for example around 0.1 w / v%. A w / v% refers to an amount of enzyme defined in grams per Litre of solution.

[0184] A volume of the hydrolysis reaction solution refers to a volume of the solvent. A volume of the hydrolysis reaction solution is not particularly limited and may be adjusted according to an amount of wool fibres to be subjected to a hydrolysis reaction and / or to adjust reaction concentration (e.g., base concentration or enzyme concentration) until it is equal to a predetermined value. In some embodiments, a volume of the hydrolysis reaction solution may be around 1 litre, for example around 2 litres, for example around 5 litres, for example around 10 litres, for example around 50 litres, or for example around 100 litres. 008880825

[0185] 20

[0186] Optional additives

[0187] A cured wool article may optionally comprise additives.

[0188] In some embodiments, the cured wool article may comprise an electrical and thermal conductivity enhancer in an amount of between 0.1 wt% or more and 10 wt% or less, based on a total weight of fibres. The electrical and thermal conductivity enhancer is not particularly limited and may be selected from graphene or molybdenum disulfide.

[0189] In some embodiments, the cured wool article may comprise a thermal insulation enhancer in an amount of between 1 wt% or more and 5 wt% or less, based on a total weight of fibres. The thermal insulation enhancer is not particularly limited and may be an aerogel, for example a silica aerogel or carbon-based aerogel.

[0190] In some embodiments, the cured wool article may comprise an additive for enhancing ultraviolet radiation resistance or mechanical strength. For example, the cured wool article may comprise titanium dioxide or alumina in an amount of between 0.5 wt% or more and 20 wt% or less, based on a total weight of fibres.

[0191] In some embodiments, the cured wool article may comprise an additive for enhancing mechanical strength and increasing resistance against extraneous chemicals. For example, the cured wool article may comprise a polymer such as polyethylene or polypropylene in an amount of between 5 wt% or more and 30 wt% or less, based on a total weight of fibres.

[0192] In some embodiments, the cured wool article may comprise a colourant, such as a dye or pigment, in an amount of between 0.1 wt% or more and 3 wt% or less, based on a total weight of fibres. Some colourants may also have properties for enhancing ultraviolet radiation resistance.

[0193] In some embodiments, the cured wool article may comprise an additive for enhancing antimicrobial resistance. For example, the cured wool article may comprise nanoparticles such as silicon dioxide or silver nanoparticles in an amount of between 0.5 wt% or more and 5 wt% or less, based on a total weight of fibres.

[0194] In some embodiments, the cured wool article may comprise additives for enhancing impact resistance. For example, the cured wool article may comprise fibreglass or carbon fibres in an amount of between 5% or more and 40% or less based on a total weight of fibres, wherein the weight of fibres excludes the optional additive fibres.

[0195] Optional additives may be provided during a step of mixing additional fibres with degraded wool fibres. In some embodiments, the optional additives may be incorporated into additional fibres, optionally by coating said fibres, prior to the mixing step.

[0196] Mould for pressing and / or curing

[0197] In some embodiments, the pre-cured mixture is pressed and / or cured in a mould. When the method comprises a pressing step (c1), the pre-cured mixture may be inserted into the mould prior to pressing. Pressing and curing moulds are well-known in the art and may be selected accordingly. Mould dimensions and shape may be selected to provide a cured wool article having a predetermined shape 008880825

[0198] 21 and / or dimensions. It is believed that providing a mould for pressing and / or curing permits a pre-cured wool article to maintain its shape, thereby improving a shape and size accuracy of a corresponding cured wool article. It is also believed that curing with a mould may slow the curing process by restricting water loss, which may be favourable for fine-tuning a water content of a cured wool article.

[0199] The features disclosed in the foregoing description, or in the following claims, or in the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for obtaining the disclosed results, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

[0200] While the invention has been described in conjunction with the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. Accordingly, the exemplary embodiments of the invention set forth above are considered to be illustrative and not limiting. Various changes to the described embodiments may be made without departing from the spirit and scope of the invention.

[0201] For the avoidance of any doubt, any theoretical explanations provided herein are provided for the purposes of improving the understanding of a reader. The inventors do not wish to be bound by any of these theoretical explanations.

[0202] Any section headings used herein are for organisational purposes only and are not to be construed as limiting the subject matter described.

[0203] Throughout this specification, including the claims which follow, unless the context requires otherwise, the word “comprise” and “include”, and variations such as “comprises”, “comprising”, and “including” will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

[0204] It must be noted that, as used in the specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” one particular value, and / or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by the use of the antecedent “about,” it will be understood that the particular value forms another embodiment. The term “about” in relation to a numerical value is optional and means for example + / - 10%.

[0205] Examples

[0206] Materials and methods

[0207] Ingredients for preparing articles were obtained as follows.

[0208] Wool Fibers were provided as scoured sheep wool, sourced from Welsh mountain sheep. 008880825

[0209] 22

[0210] Bases:

[0211] Sodium hydroxide = sodium hydroxide pellets, 500 g, purchased from Breckland Scientific (CAS number = 1310-73-2).

[0212] Potassium hydroxide = potassium hydroxide pellets, 500 g, purchased from Brekland Scientific (CAS number = 215-181-3).

[0213] Equipment for blending, chopping and mixing:

[0214] Blender = Ninja® food processor BN650UK.

[0215] Chopping equipment = Retsch® CUTTING MILL SM 100, with a sieve having a fineness (mesh size or aperture size) of 10 to 20 mm.

[0216] Planetary mixer = Vospeed Stand Mixer, with 8 L stainless steel mixing bowl.

[0217] Hydrolysis reaction temperature

[0218] Hydrolysis reactions were performed using a temperature-controlled oven having a thermostat. An oven temperature (corresponding to the hydrolysis reaction temperature) was set according to a predetermined value, and the oven was allowed to equilibrate to the predetermined value, prior to conducting the hydrolysis reaction.

[0219] Compressive strength testing

[0220] The compressive strength at 10% strain of a cured wool article was measured following BS EN ISO 29469:2022, using disc shape specimens having a diameter of 160 mm. A Mecmesin Multitest-1 dv universal mechanical tester was used for testing.

[0221] Thermal conductivity testing

[0222] The thermal conductivity of a cured wool article is measured in line with BS EN 12667:2001 , using a FOX 305 Heat flow Meter which was designed according to ASTM C518 and ISO 8301 standards.

[0223] Water vapour transmission testing

[0224] The water vapour transmission (WVTR) of a cured wool article is measured in line with ISO 15106-3 using a Versaperm WVTR meter Mk IV. Measured articles have a thickness of 20 mm, and measurements are taken at 23 °C and at 100% relative humidity.

[0225] The Vapour resistance (in units of MNs / g) of a cured wool article is calculated directly from measured water vapour transmission rate values.

[0226] Production of test samples

[0227] Table 1 lists the composition of each of the cured wool articles evaluated herein, according to weight fraction of degraded wool fibres.

[0228] The test samples 1-4 and 9-11 of Table 1 (Examples 1-4 and 9-11) are produced according to the following steps: 008880825

[0229] 23

[0230] (i) Wool fibres are provided by weighing into a vessel (for example, a beaker or reaction flask) according to a predetermined amount.

[0231] (ii) A hydrolysis reaction solution is prepared by adding water to a beaker, until an amount of water is equal to a predetermined amount, and base (e.g., sodium hydroxide) is subsequently added until the hydrolysis reaction solution has a base concentration according to a predetermined value.

[0232] (iii) The hydrolysis reaction solution is stirred until all base is dissolved.

[0233] (iv) Wool fibres from step (i) are added to the hydrolysis reaction solution.

[0234] (v) The hydrolysis reaction solution containing wool fibres is heated in an oven at 60 °C for two hours to degrade the wool fibres, before removing and cooling to ambient temperature.

[0235] (vi) Degraded wool fibres (wool pulp) are separated from the resultant keratin solution by filtering with a sieve.

[0236] (vii) Degraded wool fibres are blended in an amount of water for around 30 seconds. An amount of water for blending is around 10 times the weight of wool fibres weighed in step (i), but other amounts of water may be used.

[0237] (viii) An additional amount of water is added to the blended mixture. The additional amount of water is around five times the weight of wool fibres weighed in step (i), but other amounts of water may be used.

[0238] (ix) Additional chopped wool fibres (Examples 1-4; Method Type ‘A’ according to Table 1) or unchopped wool fibres (Examples 9-11 (reference); Method Type ‘C’ according to Table 1) are added to the blended mixture, until a predetermined weight fraction of degraded wool fibres is reached.

[0239] (x) The mixture of additional chopped wool fibres and degraded wool fibres (pre-cured mixture) are mixed in the water for around two minutes, with mechanical stirring.

[0240] (xi) Together, the mixture of additional chopped wool fibres and degraded wool fibres are removed from the water and pressed, optionally in a mould. Pressing is performed at a pressure of 96 kPa to release effluent from the mixture. Pressing is performed until no more effluent release is observed.

[0241] (xii) The pressed mixture rinsed with water in an amount around fifteen times the weight of the wool provided in step (i), but other amounts of water may be used.

[0242] (xiii) Pressing is repeated, optionally in a mould (if used), at a pressure of 96 kPa, to release effluent from the mixture. Pressing is performed until no more effluent release is observed.

[0243] (xiv) The pressed mixture (also termed pre-cured wool mixture) is removed from the mould (if used) and cured at 180 °C for 3 hours or at 60 °C for 16 hours, to afford a cured wool article. 008880825

[0244] 24

[0245] The test samples 5-8 and 12-15 of Table 1 (Examples 5-8 and 12-15) are produced according to the following steps:

[0246] (i) Chopped wool fibres (Examples 5-8; Method Type ‘B’ according to Table 1) or unchopped wool fibres (Examples 12-15 (reference; Method Type ‘C’ according to Table 1) are provided by weighing into a vessel (for example, a beaker or reaction flask) according to a predetermined amount.

[0247] (ii) A hydrolysis reaction solution is prepared by adding water to a beaker, until an amount of water is equal to a predetermined amount, and base (e.g., sodium hydroxide) is subsequently added until the hydrolysis reaction solution has a base concentration according to a predetermined value.

[0248] (iii) The hydrolysis reaction solution is stirred until all base is dissolved.

[0249] (iv) Wool fibres from step (i) are added to the hydrolysis reaction solution.

[0250] (v) The hydrolysis reaction solution containing wool fibres is heated in an oven at 60 °C for 30- 60 minutes to degrade the wool fibres, before removing and cooling to ambient temperature. The hydrolysis reaction duration is determined according to a target cured wool article density.

[0251] (vi) Degraded wool fibres (wool pulp) are separated from the resultant keratin solution by filtering with a sieve.

[0252] (vii) The degraded wool fibres are pressed, optionally in a mould. Pressing is performed at a pressure of 96 kPa, to release effluent from the mixture. Pressing is performed until no more effluent release is observed.

[0253] (viii) The pressed mixture (also termed pre-cured wool mixture) is removed from the mould (if used), and cured at 180 °C for 3 hours or at 60 °C for 16 hours, to afford a cured wool article.

[0254]

[0255] Chopped wool fibres are provided for mixing step (c);2Chopped wool fibres are provided for step (a).

[0256] 008880825

[0257] 27

[0258] Discussion

[0259] Example 1

[0260] A test samples were prepared using materials and methods as described in Table 1 . That is, the sample (cured wool article) according to Example 1 comprises sheep wool (unchopped wool fibres for step (a) (providing wool fibres) and chopped wool fibres for step (c) (mixing with additional fibres)) and is processed according to Method Type ‘A’.

[0261] 200 g wool fibres are provided for the first step of the method. The wool fibres are degraded in a 2000 mL solution of 20 g / L NaOH, at a hydrolysis reaction temperature of 60 °C for a reaction duration of 120 minutes. After cooling and filtration, degraded wool fibres are blended in 2000 mL water for 30 seconds. An additional 1000 mL water is added to the blended mixture, followed by 200 g additional chopped wool fibres. The mixture is mixed in a planetary mixer for 2 minutes, before being separated from the water and being placed in a disc-shaped mould and pressed. After pressing, the mixture is rinsed with 1500 mL water, without being removed from the mould, and then re-pressed. After re-pressing, the pre-cured mixture is removed from the mould and is cured at a temperature of 180 °C for 3 hours to afford a cured wool article.

[0262] The cured wool article has a thickness of around 26.1 mm and a diameter around 32 cm.

[0263] A compressive strength of 9.26 kPa is observed along with a sample density of around 156 kg / m3. From this Example, it is evident that articles according to the present invention can have an excellent balance of compressive strength and insulating ability, considering the high compressive strength for the density. Articles according to the present invention are therefore desirable for construction purposes as compared to cured wool articles produced by known methods, which achieve inferior compressive strength for a similar density (see reference Example 7).

[0264] Examples 2-4

[0265] Example 2 is produced as Example 1 , except that a weight fraction of degraded wool fibres is lower, at a value of 0.33.

[0266] Example 3 is produced as Example 1 , except that a weight fraction of degraded wool fibres is lower, at a value of 0.25.

[0267] Example 4 is produced as Example 1 , except that a weight fraction of degraded wool fibres is lower, at a value of 0.20.

[0268] Samples according to Examples 2-4 exhibit a lower compressive strength than samples according to Example 1 , but also exhibit a lower density (corresponding to a higher insulating ability). Samples according to Examples 2-4 exhibit an excellent balance of compressive strength and density, and in turn have an excellent balance of compressive strength and insulating ability as compared to cured wool articles produced by known methods. 008880825

[0269] 28

[0270] Thermal conductivity results

[0271] Articles produced according to the present invention (for example, in line with Examples 1 to 4) are observed to possess favourable thermal conductivity properties comparable to sheep wool, which is known to exhibit thermal conductivity in the range of from about 0.038 to about 0.054 W / m K.

[0272] For example, a cured wool article test sample produced according to the above steps (i) to (xiv) (outlined above for Examples 1 to 4 of the present invention), having a thickness of around 30.9 mm, a diameter around 32 cm, and a density of around 189.8 kg / m3exhibits a thermal conductivity of 0.041 W / m K as measured according to the measurement methods of the description. As such, cured wool articles produced according to the present invention retain favourable thermal conductivity properties as compared to sheep wool, which is correspondingly known to possess favourable thermal conductivity (insulating) properties.

[0273] Water vapour transmission results

[0274] Articles produced according to the present invention (for example, in line with Examples 1 to 4) are observed to possess favourable ‘breathability’ in terms of water vapour transmission and a corresponding vapour resistance properties. That is, a cured wool article test sample produced according to the above steps (i) to (xiv) (outlined above for Examples 1 to 4 of the present invention), having a thickness of around 20 mm and a diameter of around 32 cm, exhibits a water vapour transmission rate (WVTR) of 57.5 g / m2day at a temperature of 23 °C and a relative humidity of 100%. The article also exhibits a favourably low vapour resistance of 0.803 MNs / g.

[0275] As such, cured articles produced according to the present invention retain favourable ‘breathability’ and properties as compared to sheep wool, which is correspondingly known to possess favourable breathability properties.

[0276] Example 5 (reference)

[0277] A test sample was prepared using materials and method parameters as described in Table 1 . That is, the sample (cured wool article) according to Example 5 (reference) comprises chopped wool for step (a) and is processed according to Method Type ‘B’.

[0278] 300 g wool fibres are provided for the first step of the method. The chopped wool fibres are degraded in a 3000 mL solution of 10 g / L NaOH, at a hydrolysis reaction temperature of 60 °C for a reaction duration of 30-60 minutes. After cooling and filtration, the degraded wool fibres separated from the water, placed in a disc-shaped mould, and pressed. After pressing, the pre-cured mixture is removed from the mould and is cured at a temperature of 180 °C for 3 hours to afford a cured wool article.

[0279] The cured wool article has a thickness of around 41.1 mm and a diameter around 32 cm.

[0280] A compressive strength of 1 .18 kPa is observed along with a sample density of around 105 kg / m3. From this Example, it is evident that articles produced according to known methods have an inferior balance of compressive strength and insulating ability (corresponding to density; see Example 3 for comparison). 008880825

[0281] 29

[0282] Additionally, because all wool used for Example 5 is subjected to a hydrolysis reaction, it is believed that the wicking structure of wool is not intact in cured wool articles. By contrast, because a mixture of degraded wool fibres and additional fibres are used for methods of the present invention, an amount of wicking structure of wool is intact in cured wool articles, thereby improving insulating ability.

[0283] Examples 6-8 (reference)

[0284] Example 6 is produced as Example 5, except that a hydrolysis reaction duration is 60 minutes.

[0285] Example 7 is produced as Example 5, except that a base concentration is 20 g / L.

[0286] Example 8 is produced as Example 5, except that a hydrolysis reaction duration is 60 minutes and a base concentration is 20 g / L.

[0287] Samples according to Examples 6-8 exhibit higher compressive strength and density than samples according to Example 5. Samples according to Examples 6-8 exhibit an inferior balance of compressive strength and density, and in turn an inferior balance of compressive strength and insulating ability as compared to cured wool articles of the present invention.

[0288] Examples 9-11 (reference)

[0289] Examples 9-11 (reference) are produced as Example 1 , with unchopped wool being used for steps (a) (providing wool fibres) and (c) (mixing with additional fibres).

[0290] Additionally, Example 10 is produced as Example 1 , except that a weight fraction of degraded wool fibres is lower, at a value of 0.33.

[0291] Additionally, Example 11 is produced as Example 1 , except that a weight fraction of degraded wool fibres is lower, at a value of 0.25.

[0292] Samples according to Examples 9-11 exhibit an inferior balance of compressive strength and density, and in turn an inferior balance of compressive strength and insulating ability as compared to cured wool articles of the present invention, even though articles comprise a mixture of degraded wool fibres and additional (non-degraded) fibres.

[0293] Examples 12-15 (reference)

[0294] Examples 12-15 (reference) are produced as Example 5, except that unchopped wool is used for step (a) (providing wool fibres).

[0295] Additionally, Example 13 is produced as Example 5, except that a hydrolysis reaction duration is 60 minutes.

[0296] Additionally, Example 14 is produced as Example 5, except that a base concentration is 20 g / L.

[0297] Additionally, Example 15 is produced as Example 5, except that a hydrolysis reaction duration is 60 minutes and a base concentration is 20 g / L. 008880825

[0298] 30

[0299] Samples according to Examples 12-15 exhibit an inferior balance of compressive strength and density, and in turn an inferior balance of compressive strength and insulating ability as compared to cured wool articles of the present invention.

[0300] Conclusions The examples show that an improved balance of compressive strength and density is exhibited when cured wool articles comprise a mixture of degraded wool fibres and chopped additional (non-degraded) fibres. In turn, an improved balance of compressive strength and insulating ability is exhibited. Such cured wool articles can also exhibit favourable ‘breathability’ properties and thermal conductivity.

[0301] Additionally, cured wool articles comprising only degraded wool fibres (and not additional non-degraded wool fibres) comprise lower amounts of a wicked structure or are entirely absent of a wicked structure.

[0302] Such a cured wool article comprising only degraded wool fibres exhibits a decreased balance of mechanical strength and density when the degraded wool is unchopped wool, rather than chopped wool. Correspondingly, methods of the present invention, afford cured wool articles having an improved balance of said properties.

Claims

00888082531Claims:1 . A method for producing a cured wool article, the method comprising steps:(a) providing wool fibres;(b) performing a hydrolysis reaction on the wool fibres to provide degraded wool fibres;(c) mixing the degraded wool fibres with additional fibres to provide a pre-cured wool mixture, wherein the additional fibres are chopped fibres; and(d) curing the pre-cured wool mixture to afford a cured wool article.

2. The method for producing a cured wool article according to claim 1 , wherein the additional fibres are wool fibres.

3. The method for producing a cured wool article according to claim 1 or 2, wherein the precured wool mixture has a predetermined weight fraction of degraded wool fibres, wherein the weight fraction of degraded wool fibres is from around 0.05 to 0.75 and is determined according to the method of the description.

4. The method for producing a cured wool article according to any one of claims 1-3, wherein step (b) comprises contacting the wool fibres with a hydrolysis reaction solution.

5. The method for producing a cured wool article according to claim 4, wherein the hydrolysis reaction is a base-mediated hydrolysis reaction, wherein the hydrolysis reaction solution comprises a base according to formula (I):Xn(OH)mformula (I) wherein in formula (I), X is any one of Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, or Ba, wherein when X is Li, Na, K, Rb, or Cs, n = 1 and m = 1 , and wherein when X is Be, Mg, Ca, Sr, or Ba, n = 2 and m = 2.

6. The method for producing a cured wool article according to claim 5, wherein the basemediated hydrolysis reaction is performed at a reaction temperature of from about 40 °C to about 250 °C, wherein the reaction temperature is measured according to the method of the description.

7. The method for producing a cured wool article according to claims 5 or 6, wherein the basemediated hydrolysis reaction is performed for a reaction duration of around 120 minutes.

8. The method for producing a cured wool article according to any one of claims 5-7, wherein the base wherein in step (b) the base-mediated hydrolysis reaction is performed at a base concentration of between around 5 g / L or more and 100 g / L or less, optionally between around 10 g / L or more and 20 g / L or less.008880825329. The method for producing a cured wool article according to any one of claims 5-8, wherein the base is selected from NaOH or KOH, optionally wherein the base is NaOH.

10. The method for producing a cured wool article according to claim 4, wherein the hydrolysis reaction is an enzyme-mediated hydrolysis reaction, wherein the hydrolysis reaction solution comprises an enzyme for hydrolysing keratin.11 . The method for producing a cured wool article according to claim 10, wherein the enzyme is a keratinase, or wherein the enzyme is selected from the group consisting of a protease, papain, and a collagenase.

12. The method for producing a cured wool article according to any one of claims 4-6, or 8-11 , wherein the hydrolysis reaction is performed until a percentage concentration of soluble keratin degradation products dissolved in the hydrolysis reaction solution is between from around 20% to around 75%, wherein the percentage concentration of soluble keratin degradation products is measured according to the method of the description.

13. The method for producing a cured wool article according to claim 12, wherein the hydrolysis reaction is performed until a percentage concentration of soluble keratin degradation products is between from around 35% to around 55%.

14. The method for producing a cured wool article according to any one of the preceding claims, wherein: the method further comprising a step (a1), wherein step (a1) comprises scouring wool after step (a) and before step (b); or wherein the wool provided in step (a) is scoured wool.

15. The method for producing a cured wool article according to any one of the preceding claims, further comprising a step (b1), wherein step (b1) comprises blending the degraded wool fibres produced in step (b), wherein step (b1) is performed after step (b1) and before step (c).

16. The method for producing a cured wool article according to any one of the preceding claims, further comprising a step (c1), wherein step (c1) comprises pressing the pre-cured wool mixture, wherein step (c1) is performed after step (c) and before step (d).

17. The method for producing a cured wool article according to claim 16, wherein step (c1) further comprises inserting the pre-cured mixture into a mould prior to pressing.

18. The method for producing a cured wool article according to any one of the preceding claims, wherein step (b) further comprises separating degraded wool fibres from a keratin solution after performing the hydrolysis reaction.0088808253319. The method for producing a cured wool article according to any one of the preceding claims, wherein in step (c), mixing comprises stirring the degraded wool fibres with the additional fibres.

20. The method for producing a cured wool article according to any one of the preceding claims, wherein: the additional fibres have a clump length of between around 1 cm or more and around 5 cm or less; or wherein the method comprises (i) providing additional fibres, and (ii) cutting the additional fibres to provide chopped fibres having a predetermined clump size.21 . The method for producing a cured wool article according to claim 20, wherein the predetermined clump size is a clump length.

22. A cured wool article produced according to a method of any one of claims 1-21 .

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