Home compostable heat-sealable non-woven material, methods of manufacture thereof and articles comprising the same

Abstract

Disclosed herein is a non-woven that comprises a heat-seal composition comprising 55 to 75 wt% of poly(butylene succinate-co-adipate); and 25 to 45 wt% of polybutylene succinate, based on a total weight of the heat seal composition, where the non-woven is home compostable.

Description

HOME COMPOSTABLE HEAT-SEALABLE NON-WOVEN MATERIAL, METHODS OF MANUFACTURE THEREOF AND ARTICLES COMPRISING THE SAMEBACKGROUND

[0001] This disclosure relates to a home compostable heat-sealable non-woven material, methods of manufacture thereof and articles comprising the same. In particular, disclosed herein is a heat-sealable cellulosic non-woven that is home compostable and outdoor compostable and that can be used for example, as a beverage filter material and as packaging materials for food items and agricultural products.

[0002] The use and production of sustainable materials is becoming increasingly desirable due to regulations that pertain to environmental protection standards. In particular, there has been an interest in developing compostable materials for use in, for example, beverage filters, food packaging, packaging, or agricultural or horticultural wrapping papers. Nevertheless, there remains a need for improved materials for use in such applications.

[0003] Current heat-sealable non-wovens comprise thermoplastic polymer fibers such as polyethylene and polypropylene which are typically non-biodegradable. Furthermore, the known biodegradable polymers have a melting temperature around 80°C which can impact the runnability of the manufacturing of such heat-sealable non-wovens and also the runnability of the converting step of these heat-sealable non-wovens as they can melt or stick to some of the machine parts. Moreover, the known biodegradable cannot be spun into a fiber, hence can only be applied as an emulsion.

[0004] Accordingly, there are remaining needs to provide a non-woven material having heat- sealable properties and being at the same time biodegradable under domestic conditions. Furthermore, there are still some unresolved needs to propose a non-woven material having heat-sealing and biodegradable properties having a good runnability on the converting machines and also during its manufacturing process.SUMMARY|0005| The present invention relates to a non-woven comprising a heat-seal composition. The heat-seal composition comprises:55 to 75 wt% of poly(butylene succinate-co-adipate); and25 to 45 wt% of polybutylene succinate, based on a total weight of the heat seal composition, where the non-woven is home compostable.

[0006] The heat-seal composition can be in fiber form or in the form of a dispersion.

[0007] According to an embodiment, the non-woven is a wet-laid non-woven.

[0008] The non-woven may have a basis weight of 10 to 100 g / m2.

[0009] The non-woven can be a single ply.

[0010] The non-woven can comprise at least two plies, preferably the exterior ply of the non-woven comprises the heat-seal composition.

[0011] The non-woven can comprise the heat-seal composition in an amount of 1 to 25 wt% based on a total weight of the non-woven.

[0012] The non-woven can comprise 75 to 99 wt% of cellulosic fibers based on the total weight of the non-woven.

[0013] The non-woven may comprise supplementary heat-sealable fibers selected from polylactic acid, polylactic acid blended with another compostable polymer such as polylactic acid-polyhydroxyalkanoate blends, polylactic acid-polycaprolactone blends, such that the total polylactic acid content is in an amount of less than 12 wt% preferably less than 10 wt% based on a total weight of the non-woven.

[0014] According to an embodiment, when the non-woven comprises at least two plies, the supplementary heat-sealable fibers are mixed with the heat-seal composition in the exterior ply.

[0015] The supplementary heat-sealable fibers can have a length between 1 and 20 mm preferably between 2 and 10 mm and / or a linear density between 0.1 and 5 dtex.

[0016] The supplementary heat-sealable fibers can be short-cut fibers.

[0017] The fibers of the heat-seal composition may have a length between 1 and 20 mm preferably between 2 and 10 mm and / or a linear density between 0.1 and 5 dtex.

[0018] The fibers of the heat-seal composition can be short-cut fibers.

[0019] The heat-seal composition has a melting temperature of at least 100°C.

[0020] According to an embodiment, the fibers of the heat-seal composition can be mono-component fibers.

[0021] According to a further embodiment, the fibers of the heat-seal composition can be bi-component fibers.

[0022] The fibers of the heat-seal composition can comprise a blend of poly(butylene succinate-co-adipate) and polybutylene succinate.

[0023] The fibers of the heat-seal composition can comprise polybutylene succinate fibers and poly(butylene succinate-co-adipate) fibers and where the polybutylene succinatefibers are devoid of poly(butylene succinate-co-adipate) and where the poly(butylene succinate-co-adipate) fibers are devoid of polybutylene succinate.

[0024] The present invention also relates to a heat-seal article comprising the nonwoven as defined here- above.

[0025] The heat-seal article can be a tea bag, a coffee bag, an herbal sachet, a food packaging article, a medical packaging article, a horticultural wrapping paper, a cook- in bag or a bag for particulate liquid cleansing agents.

[0026] The present invention also relates to a method of manufacturing a non-woven as defined herein-above. The method comprises a step of providing a slurry comprising cellulosic fibers; followed by a step of forming a non-woven wet-laid on a forming wire; and then a step of at least partially drying the non-woven wet-laid. The method further comprises a step of providing a heat-seal composition, said heat-seal composition comprises 55 to 75 wt% of poly(butylene succinate-co-adipate) and 25 to 45 wt% of polybutylene succinate, based on the total weight of the heat-seal composition.

[0027] The heat-seal composition used in this method can be in the form of a dispersion and it is applied to the non-woven wet-laid after the step of at least partially drying the non-woven wet-laid.

[0028] The heat-seal composition used in this method can be in the form of fibers and is provided to the slurry before the step of forming a non-woven wet-laid on the forming wire.

[0029] The fibers of the heat-seal composition can be bicomponent fibers.

[0030] The fibers of the heat-seal composition can be monocomponent fibers.

[0031] When the method comprises using fibers for the heat-seal composition, at least a portion of said fibers of the heat-seal composition are produced by the following steps: melting the poly(butylene succinate-co-adipate) and the polybutylene succinate; spinning the melted poly(butylene succinate-co-adipate) and the polybutylene succinate to form filaments; and cutting the filaments to form the fibers of the heat-seal composition.

[0032] According to this method, at least a portion of the poly(butylene succinate-co- adipate) and the polybutylene succinate are melt-blended before the spinning step.

[0033] The fibers of the heat-seal composition can have a length between 1 and 20 mm, preferably between 2 and 10 mm and / or a linear density between 0.1 and 5 dtex.

[0034] The non-woven manufactured by this method can comprise the heat seal composition in an amount of 1 to 25 wt% based on the total weight of the non-woven.

[0035] The non-woven manufactured by this method can comprise cellulosic fibers in an amount of 75 to 99 wt%, based on a total weight of the non-woven.

[0036] The method can further comprise a step of providing supplementary heat- sealable fibers to the slurry, said step of providing supplementary heat-sealable fibers to the slurry being performed prior to the step of forming the non-woven wet-laid on the forming wire.

[0037] The supplementary heat-sealable fibers used in this manufacturing method can be selected from polylactic acid, polylactic acid blended with another compostable polymer such as polylactic acid-polyhydroxyalkanoate blends, polylactic acid-polycaprolactone blends, such that the total polylactic acid content is in an amount of less than 12 wt%, preferably less than 10 wt%, based on the total weight of the non-woven.

[0038] The supplementary heat-sealable fibers used in this method may have a length between 1 and 20 mm, preferably between 2 and 10 mm and / or a linear density between 0.1 and 5 dtex.

[0039] The supplementary heat-sealable fibers can be blended with the heat-seal composition before the step of providing the non-woven with the heat-seal composition.BRIEF DESCRIPTION OF THE FIGURES

[0040] FIG. 1 A is a schematic illustration of an embodiment in which the non-woven is a single ply non-woven and comprises a heat-seal composition in the form of fiber;

[0041] FIG. IB is a schematic illustration of an embodiment in which the non-woven is a single ply non-woven and comprises a heat-seal composition in the form of fiber and supplementary heat-sealable fibers;

[0042] FIG. 1C is a schematic illustration of an embodiment in which the non-woven is a single ply non-woven and comprises a heat-seal composition in the form of dispersion;

[0043] FIG. ID is a schematic illustration of an embodiment in which the non-woven is a single ply non-woven and comprises a heat-seal composition in the form of a dispersion which forms a film on one side of the non-woven;

[0044] FIG. 2A is a schematic illustration of an embodiment in which the non-woven is a two ply non-woven and comprises a heat-seal composition in the form of fibers in one of the plies;

[0045] FIG. 2B is a schematic illustration of an embodiment in which the non-woven is a two ply non-woven and comprises a heat-seal composition in the form of fibers and supplementary heat-sealable fibers in one of the plies;

[0046] FIG. 2C is a schematic illustration of an embodiment in which the non-woven is a two ply non-woven and comprises a heat-seal composition in the form of dispersion in one of the plies.

[0047] FIG. 3 is a graph that depicts the home biodegradation rate in percentage versus time in days for Sample #1 through Sample #5;

[0048] FIG. 4 is a graph that depicts the home biodegradation rate in percentage versus time in days for Sample #6 through Sample #8; and

[0049] FIG. 5 is a graph that depicts the biodegradation rate for a purely cellulose sample and one that has the heat-seal fibers disclosed herein.DETAILED DESCRIPTIONDefinitions|0050| Unless otherwise specified, the term “PBS fibers” and the term “PBSA fibers” imply that these fibers contain polybutylene succinate (PBS) homopolymer and poly(butylene succinate-co-adipate (PBSA) homopolymer respectively.

[0051] The term “bicomponent fibers” implies that the PBS and PBSA are intimately blended together, or alternatively, copolymerized to form fibers that are in a core-sheath configuration. In the core sheath fibers, the PBSA (the lower melting point material) forms the sheath, while the PBS (the higher melting point material) forms the core.

[0052] Biodegradable refers to the ability of a substance or material to be broken down naturally by microorganisms, such as bacteria, fungi, or other biological processes, into simpler, non-toxic substances, like water, carbon dioxide, and biomass. This breakdown occurs over time and leaves no harmful residues, allowing the material to be reintegrated into the natural environment.

[0053] The biodegradability of the samples is determined as follows. The disintegration of samples placed in a compost bin at room temperature and pressure is measured over a period of 6 months. The samples all have the same grammage and test area. Samples are placed in a compost bin and covered in soil. The disintegration of the samples is measured over a period of 6 months, by visual inspection, and samples which have beencompletely digested are no longer visible. Samples are considered fully biodegradable if they disintegrate completely by 6 months (180 days).

[0054] The EN 13432 standard is an European industrial compostability certification for packaging materials. It specifies the requirements for packaging recoverable through composting and biodegradation, ensuring that the material can be processed in industrial composting facilities without negatively impacting the environment. The material must biodegrade into carbon dioxide, water, and biomass through microbial action. This is assessed by measuring the amount of carbon dioxide produced when the material is composted. At least 90% of the organic carbon in the material must convert to CO2 within 180 days. The material must break down into fragments that are indistinguishable in the compost. After 12 weeks, less than 10% of the original material's dry weight should remain on a 2 mm sieve.

[0055] The expression “compostable” may be generally defined in line with EN13432 standard. The expression “compostable” when applied to a material or a product means that the material, or the entire product, will both biodegrade and disintegrate.|0056| A “compostable material” refers to a material comprising a maximum of 10% by weight of non-compostable components, thereby meeting EN13432.

[0057] By the term “disintegrates” it is meant that the material, or the product made from it, will physically fall apart into fine visually indistinguishable fragments, at the end of a typical composting cycle.

[0058] An “industrially-compostable material” refers to a material that disintegrates at a temperature between 55 to 60°C in less than 3 months and biodegrades at a temperature between 55 to 60°C in less than 6 months as outlined in EN13432.

[0059] A “home-compostable material” refers to a material that disintegrates at a temperature between 20 to 30°C, in less than 6 months and biodegrades at a temperature between 20 to 30°C, in less than 12 months. The home compostability test can be carried out following EN13432 except for the disintegration and biodegradation temperatures and durations as indicated above.

[0060] The “OK Compost Home” certification is a certification provided by TUV Austria (formerly Vincotte) that ensures a product or material is compostable in a home composting environment. This certification indicates that the product can break down in a home compost pile under typical home composting conditions, without harming theenvironment or leaving toxic residues. Generally, this period is around 6 months, but it may vary based on specific requirements and conditions.

[0061] Dtex (decitex) is a unit of measure used to describe the linear density of fibers, particularly in textiles. It indicates the mass in grams per 10,000 meters of a fiber. In simple terms, dtex measures the thickness or fineness of a fiber.Detailed Description

[0062] Disclosed herein is a biodegradable non-woven that comprises heat-seal composition. The heat-seal composition comprises 55 to 75 wt% of poly(butylene succinate- co-adipate) (PBSA) and 25 to 45 wt% of polybutylene succinate (PBS) based on the total weight of the heat-seal composition.

[0063] Referring now to the drawings, like parts are marked throughout the specification and drawings with the same reference numerals, respectively. Drawing figures are not necessarily to scale and in certain views, parts may have been exaggerated for purposes of clarity.100641 FIG.1 A shows a non-woven 1 comprising the heat-seal composition in the form of fibers 11 that are uniformly distributed in the non-woven 1.

[0065] In an embodiment, the non-woven 1 may further comprise naturally-occurring biodegradable fibers and / or synthetically-manufactured biodegradable fibers. The naturally- occurring biodegradable fibers may include cellulosic fibers 10. The non-woven 1 may comprise 75 to 99 wt% of cellulosic fibers 10 based on the total weight of the non-woven 1. The synthetically-manufactured biodegradable fibers may include heat sealable fibers such as polylactic acid and / or man-made cellulosic fibers such as Lyocell or Rayon.

[0066] The non-woven 1 comprises the heat-seal composition in an amount of 1 to 25 wt%, preferably 5 to 20 wt%, more preferably 8 to 18 wt%, based on the total weight of the non-woven 1. Within this range a satisfactory heat-seal property for the non-woven 1 can be obtained.

[0067] The non-woven 1 may further comprise supplementary heat seal fibers 12 as depicted on FIG. IB. The addition of supplementary heat-sealable fibers 12 increases the seal strength of the non-woven material 1. Notably, the use of polylactic acid, polylactic acid blended with another compostable polymer such as polylactic acid-polyhydroxyalkanoate blends, polylactic acid-polycaprolactone blends as supplementary heat-sealable fibers 12 is advantageous because they are biodegradable under industrial composting conditions.Furthermore, when the content of polylactic acid is less than 12 wt%, preferably less than 10wt% based on the total weight of the non-woven, the non-woven will remain home compostable.

[0068] In further embodiments, represented in FIG. 1C and FIG. ID, the heat seal composition can be in the form of a dispersion 14. In other words, the intimate blend of PBS and PBSA may be stabilized in a liquid such as water to form a dispersion. The dispersion 14 may then be used to impregnate (FIG. 1C) and / or coat (FIG. ID) the non-woven 1. FIG. 1C shows a non-woven 1 impregnated with a dispersion 14 comprising 55 to 75 wt% of poly(butylene succinate-co-adipate) (PBSA) and 25 to 45 wt% of polybutylene succinate (PBS) based on the total weight of the heat-seal composition. The heat-seal composition coats the fibers of the non-woven 1 and is evenly distributed in the non-woven 1 as shown on FIG. 1C. The impregnation can be carried out using a size-press treatment. In an embodiment shown on FIG. ID, the heat seal composition is applied as a dispersion 14 on the non-woven 1 and substantially forms a film at the surface of the non-woven 1 with minimal penetration in the core of the non-woven 1. Accordingly, one side of the non-woven would be heal-sealable while the opposite side remains non-heat sealable. In order, to form a heatseal composition film at the surface of the non-woven, the dispersion is preferably applied using curtain coating or gravure coating methods.

[0069] In an embodiment, the non-woven 1 may be composed of a single ply that is used in an article (such as a tea bag, a coffee pod, a coffee filter, a food packaging material, a packaging material, or an agricultural or a horticultural wrapping paper, or the like). Examples of single ply non-wovens 1 are depicted in FIGs. 1A-1D.

[0070] In an embodiment, the non-woven 1 may comprise multiple plies, for example, at least two plies and preferably the heat-seal composition located as an exterior ply of the non-woven 1. Since the heat-seal composition is in an exterior ply of the non-woven 1, it has a heat-sealable surface. FIGs. 2A-2C show a non-woven 1 with a first ply 20 and a second ply 21. The first ply 20 forms a non-heat sealable side and the second ply 21 forms a heat-sealable side of the non-woven 1 and is an exterior ply of the non-woven 1. Having a heat-sealable side and a non-heat sealable side enables easier processing and prevents the first ply 20 (which serves as an insulating layer) from sticking to the heated clamp during the heatseal process.

[0071] In the embodiment represented in FIG. 2 A, the non-woven 1 comprises mainly cellulosic fibers 10 in its first ply 20 and the heat-seal composition in the form of fibers 11 in the second ply 21.

[0072] In the embodiment represented in FIG. 2B, the non-woven 1 comprises mainly cellulosic fibers 10 in its first ply 20 and the second ply 21 contains the heat-seal composition in the form of fibers 11, supplementary heat-sealable fibers 12 and cellulosic fibers 10. According to this embodiment, the supplementary heat-sealable fibers 12 are mixed with the heat-seal composition in the exterior ply.

[0073] In the embodiment represented in FIG. 2C, the non-woven 1 comprises mainly cellulosic fibers 10 in the first ply 20 and its second ply 21 comprises the heat-seal composition in the form of a dispersion 14 impregnating the second ply 21.

[0074] In an embodiment, the heat-sealable composition (in either fiber or dispersion form) has a melting temperature of at least 100°C and can be used in applications that involve the use of boiling water.

[0075] The non-woven 1 is home-compostable. The heat-seal composition can be in the form of fibers 11 or in the form of a dispersion 14. The term dispersion here means that the heat-seal composition is in a liquid or viscous form and is applied to the non-woven web and is aimed at penetrating at least partially in the thickness of the non-woven. When the heat-seal composition is made of fibers 11, these fibers have a length between 1 and 20 mm, preferably between 2 and 10 mm and / or a linear density between 0.1 and 5 dtex.

[0076] In an embodiment, the non-woven comprises only the heat-seal composition in the form of PBS fibers and PBSA fibers. The PBS fibers are devoid of PBSA and vice versa. The PBSA and PBS fibers may be blended together with cellulosic fibers 10 to form the nonwoven 1.

[0077] In another embodiment, the non-woven 1 can comprise monocomponent fibers that comprise PBS and PBSA intimately blended together in a melt or in solution and then spun (from the melt or from solution) to form a monocomponent fiber. The monocomponent fiber has the PBS and the PBSA in a single phase.

[0078] In yet another embodiment, the non-woven 1 comprises bicomponent fibers that comprise PBS and PBSA blended together or copolymerized, but that undergo phase separation upon being spun to form a bicomponent fiber, where the PBSA forms a first phase (e.g., the sheath) while PBS forms the second phase (e.g., the core). The bicomponent fiber can have two or more phases, each of which have a different chemical composition.

[0079] In yet another embodiment, the non-woven 1 comprises bicomponent fibers that comprise PBS and PBSA blended together in at least one phase of the bicomponent fiber. In other words, the core or the sheath or the core and the sheath of the bicomponent fiber can comprise the blend of PBS and PBSA.

[0080] In yet another embodiment, the non-woven 1 may comprise monocomponent or bicomponent fibers that are further blended with either PBS fibers, PBSA fibers or a combination of both PBS and PBSA fibers.

[0081] In a preferred embodiment, the non-woven 1 comprises monocomponent fibers that contain PBS and PBSA blended together. The two polymers are blended either in the melt or in solution, extruded and then spun into fibers on a spinneret. The fibers are then cut to a length of less than 20 mm. The monocomponent fibers comprising an intimate blend of PBS and PBSA are then manufactured into a non-woven article.

[0082] Polybutylene succinate (PBS) (sometimes written as polytetramethylene succinate) is a thermoplastic polymer resin of the polyester family. PBS is a biodegradable aliphatic polyester with properties that are comparable with polypropylene. PBS is a white crystalline thermoplastic polymer with a density of 1.25 g / cm3, a melting point (Tm) of 90 to 120°C and a low glass transition temperature (Tg) of about -45 to -10°C. It presents good mechanical properties and excellent processability in textile filaments, injection molds, and extruded and blown products.

[0083] The PBS (in the form of polymer in the dispersion or in the form of fiber or as a component of the fibers of the heat-seal composition) is present in the heat-seal composition in an amount of 25 to 45 weight percent (wt%), preferably in an amount of 32 to 43 wt%, and more preferably in an amount of 35 to 40 wt%, based on a total weight of the heat-seal composition.

[0084] Polybutylene succinate-co-adipate (PBSA) is a type of biodegradable aliphatic polyester, which is a copolymer composed of butylene succinate and butylene adipate units. The PBSA used herein comprises a copolymer of a first polymer (derived from succinic acid (HOOC-(CH2)2-COOH) and butanediol (HO-(CH2)4-OH)) and a second polymer (derived from adipic acid (HOOC-(CH2)4-COOH) and butanediol).

[0085] PBSA is known for its biodegradability, flexibility, and good mechanical properties. The presence of adipic acid improves flexibility and reduces the crystallinity of the material compared to pure PBS, giving PBSA better properties for certain applications like films or flexible packaging.

[0086] The PBS A has a density of 1.23 to 1.26 g / cm3, a melting point (Tm) of 90 to 115°C and a low glass transition temperature (Tg) of about -45 to -30°C. In general, the PBSA has a lower melting temperature and glass transition temperature than that used in the PBS fibers.

[0087] The PBSA (in the form of polymer in the dispersion or in the form of fiber or as a component of the fibers of the heat-seal composition) is present in the heat-seal composition in an amount of 55 to 75 weight percent (wt%), preferably in an amount of 57 to 68 wt%, more preferably in an amount of 60 to 65 wt%, based on a total weight of the heatseal composition.

[0088] In another embodiment, when PBS and PBSA are used in a bicomponent fiber, the lower temperature melting component lies on the outside of the fiber, while the higher temperature melting component lies on the inside of the fiber. In other words, the PBSA forms the sheath, while the PBS forms the core when the fibers are in a bicomponent configuration. This permits the lower temperature sheath to effect heat-sealing when the fibers are subjected to heat and pressure in a manufacturing process.[0089| In the bicomponent configuration, the sheath (PBSA) comprises 55 to 75 wt%, while the core (PBS) comprises 25 to 45 wt% of the bicomponent fibers.

[0090] As noted above, the non-woven may comprise other biodegradable fibers. The biodegradable fibers comprise naturally-occurring biodegradable fibers, synthetically manufactured biodegradable fibers, or a combination thereof in addition to the heat-seal composition.

[0091] Examples of naturally-occurring biodegradable fibers include cellulose, cotton, chitosan, wool, jute, hemp, silk, linen, coir, bamboo, or the like, or a combination thereof. The preferred cellulosic fibers 10 are hardwood fibers, softwood fibers and annual plant fibers. These fibers are particularly suited for beverage and food packaging applications notably because of the mechanical properties they provide to the non-woven.

[0092] Examples of synthetically-manufactured supplementary (biodegradable) heat sealable fibers that may be added to the heat seal composition include polylactic acid (PLA), polyhydroxyalkanoates (PHA), polylactic-glycolic acid (PLGA), poly-caprolactone (PCL), copolymers of polylactic-glycolic acid and poly-caprolactone (PCL-PLGA copolymer), polyhydroxy-butyrate-valerate (PHBV), polyorthoester (POE), polyethylene oxide-butylene terephthalate (PEO-PBTP), poly-D,L-lactic acid-p-dioxanone-polyethy lene glycol block copolymer (PLA-DX-PEG), or the like, or a combination thereof.

[0093] Preferred naturally-occurring biodegradable fibers may include cellulosic fibers, while preferred synthetically-manufactured biodegradable fibers may include polylactic acid (PLA) or polylactic acid blended with other biodegradable polymers.

[0094] The cellulosic fibers 10 may be co-refined, preferably at a level between 400- 500 mL CSF, more preferably between 420 and 490 ML CSF, even more preferably between 440 and 480 mL CSF

[0095] In an embodiment, the cellulosic fibers 10 may be present in the non-woven in an amount of 75 to 99 wt%, preferably 80 to 95 wt%, and more preferably 82 to 92 wt%, based on a total weight of the non-woven 1.

[0096] In a preferred embodiment, the total biodegradable content is greater than or equal to 90 wt%, preferably greater than 95 wt%, based on a total weight of the non-woven 1. It is believed that the large fibrous content provides the media with the requisite strength, pleatability and stiffness. The media is also biodegradable and compostable (both in an open air landfill and in the home) due to the large cellulosic content.

[0097] Preferred synthetically manufactured supplementary heat-sealable fibers include polylactic acid (PLA) fibers or blends of PLA. PLA fibers are eco-friendly and sustainable. PLA fibers exhibit good mechanical strength, thermal stability, and flexibility, making them suitable for use in filtration systems while also addressing environmental concerns. PLA is a biopolymer that offers the advantage of being fully biodegradable under appropriate conditions.

[0098] In an embodiment, the PLA is blended with another compostable polymer such as blends of PLA / polyhydroxyalkanoate (PHA) or blends of PLA / polycaprolactone (PCL). The PLA is preferably used in an amount of less than 12 wt%, preferably less than 10 wt%, based on a total weight of the non-woven.

[0099] The PLA or PLA blends fibers are also preferably short cut fibers and have a length between 1 and 20 mm, preferably between 2 and 10 mm and / or a linear density between 0.1 and 5 dtex.

[0100] In an embodiment, the non-woven 1 has a basis weight of between 10 and 100 g / m2. In an embodiment, the non-woven 1 has a dry heat seal strength of at least 0.30 Newtons (N), preferably at least 0.35 N. In an embodiment, the non-woven 1 has a biodegradability under home composting conditions of greater than 85%, preferably greater than 87% and more preferably greater than 90%, based on a total weight of the non-woven 1. In an embodiment, the heat-seal composition has a melting temperature of at least 100°C.

[0101] In one embodiment, in one method of manufacturing the non-woven, PBS and PBSA homopolymers are first blended in an extruder to form an intimate melt blend. The melt blend is extruded and then spun on a spinneret to manufacture monocomponent fibers. The monocomponent fibers are then cut as described below to form short cut fibers. The short cut fibers are converted into a non-woven preferably by a wet-laying process.

[0102] In an embodiment, 55 to 75wt% of PBSA and 25 to 45 wt% of PBS are blended in the extruder to make an intimate blend that is eventually converted to a monocomponent fiber. The extrudate is spun to make continuous monocomponent fibers. These continuous fibers are cut as detailed below to make short-cut fibers, which are then blended with cellulosic fibers and other biodegradable fibers and wet-laid to form the nonwoven.

[0103] Short-cut fibers are obtained by mechanical cutting, where continuous fibers are fed into a cutting machine. The machine slices the long fibers into specific short lengths based on the desired application. The cut fibers are then collected and processed further (e.g., blended with cellulosic and other biodegradable fibers) to manufacture the non-woven.[0104| The shorter length of these fibers makes them suitable for blending with other materials, improving dispersibility in composite manufacturing, and providing enhanced bonding in heat-seal applications such as non-woven fabrics, filters, or packaging materials.

[0105] In an embodiment, a non-woven ply is manufactured by blending the heatseal fibers 11 (with the fibers in short-cut form), the cellulose fibers 10 and / or the supplementary heat-sealable fibers 12 (if present) in a pulper to form a slurry. Man-made cellulosic may also added to the pulper. Water is added to the pulper to enable the formation of the slurry.

[0106] The slurry and the constituents are allowed to mix together gently before the slurry is transferred to a headbox and further diluted with water if desired. The diluted slurry is applied onto a forming wire of a papermaking machine (e.g., a fourdrinier or a rotoformer) to form non-woven wet-laid. In order to perform an at least partial drying of the non-woven wet-laid, vacuum is continuously applied during the aforementioned processes to remove the solvent from the mixture and / or the slurry, thereby producing a fibrous non-woven wet-laid. The non-woven wet-laid thus formed, is dried and wound into a roll to form a ply.

[0107] In an embodiment, the non-woven 1 may comprise a plurality of plies -notably an exterior ply comprising the fibers 11 of the heat-seal composition disclosed above or a heat-seal composition in the form of a dispersion 14 (that comprises the PBS and PBSA), andat least one further ply and / or an optional additional ply that does not contain the heat seal composition.

[0108] The at least one further ply (and the optional third ply) comprise biodegradable fibers, an optional sizing agent, and a binder that is preferably not a heat sealable binder. The composition and manufacturing of the non-woven with two plies will now be described in detail, but the description can equally apply to a non-woven with three or more plies (which will not be described in the interests of brevity). The first ply 20 is substantially free of the heat-seal composition. This enables easier processing, in particular, it prevents the first ply (which serves as an insulating layer) from sticking to the heated clamp during the heat-seal process.

[0109] The first ply 20 comprises the cellulosic fibers and a sizing agent. The first ply 20 does not comprise a binder that is a heat-sealable binder. The cellulosic fibers are similar to those listed above and will not be described in the interests of brevity. The sizing agent may comprise at least one of an alkyl ketene dimer (AKD), a soap rosin, anionic rosin, a cationic rosin, or any combination thereof. In an aspect, the sizing agent herein refers to a substance applied to fibers, yams, or fabrics to improve their properties such as strength, stiffness, processibility and abrasion resistance to fibers and yarns, and performance during subsequent processing and end-use applications. The sizing agent may be hydrophobic. For example, AKD comprises a saturated hydrocarbon chain containing fatty acids solid dimer and / or liquid emulsion, where the hydrocarbon chain contributes to its hydrophobicity. In an aspect, any suitable material used as a sizing agent and is hydrophobic, for example, a material that is non-polar or has low-polarity, or containing suitably long hydrocarbon chains (e.g., > 12 carbons), can be used. Furthermore, the presence of the sizing agent may prevent the heat-seal composition when in the form of a dispersion to penetrate in the thickness of the first ply 20.

[0110] In an aspect, a content of the sizing agent may be 0.5 wt% or more, 1 wt% or more, 2 wt% or more, and / or 5 wt% or less, 4 wt% or less, 3 wt% or less, relative to a weight of the non-woven. In another aspect, the content of the sizing agent may be 0.05 or more, 0.1 wt% or more, 0.5 wt% or more, and / or 2.65 wt% or less, 2 wt% or less, 1.5 wt% or less, lwt% or less, relative to the total weight of the non-woven.

[0111] In an aspect, the method of manufacturing the non-woven that comprises two- plies by a wet process comprises: , and dispersing the first ply 20 precursor material (the cellulosic fibers and the sizing agent) in a first pulper, and dispersing the ingredients for thesecond ply 21 (the heat-seal fibers 11 with the fibers in short-cut form, the cellulose fibers 10 and / or the supplementary heat-sealable fibers 12) in a second pulper; and wet-laying the dispersed first ply precursor material and the dispersed second ply ingredients by using a dual compartment headbox or two headboxes disposed in-line on a forming wire to form a resulting product, wherein the resulting product comprises the second ply disposed on the first ply; and drying the resulting product to manufacture a non-woven that contains two plies. Three or more plies may be manufactured in this manner by using a headbox with three or more compartments or three or more headboxes disposed in-line.

[0112] The heat-seal bag may be used in a variety of different articles. The nonwoven 1 may be used in articles such as a tea bag, a coffee bag, a herbal sachet, a cook-in bag or a bag for particulate liquid cleansing agents or for horticultural wrapping papers.

[0113] The non-wovens, method of manufacture thereof and articles comprising the same are exemplified by the following non-limiting examples.EXAMPLEExample 1

[0114] In this example, different fibrous compositions were tested to determine their biodegradability. The composition of each of the samples for this Example is detailed below along with the sample number.

[0115] Sample #1: wet-laid 100 wt% cellulose fibers.

[0116] Sample #2: wet-laid 25 wt% of short-cut polylactic acid (PLA) fibers and 75 wt% cellulose fibers.

[0117] Sample #3: wet-laid 25 wt% of short-cut PBS fibers and 75 wt% cellulose fibers.

[0118] Sample #4: wet-laid 25 wt% of short-cut PLA / polycaprolactone (PCL) fibers and 75 wt% cellulose fibers.

[0119] Sample #5: Spunbond 100 wt% of PBS.

[0120] The different samples were then subjected to a home compostability test. The home compostability test was carried out at a temperature between 20-30 °C for at least 60 days. The samples were prepared by cryogrinding to produce samples having a length of less than 4 millimeters. The graph of FIG. 3 shows the biodegradation rate over time of the different samples.

[0121] Biodegradation is measured relative to 100 wt% cellulosic material (Sample #1). Sample #1 can be considered to be fully home compostable. If a material achieves 90% of Sample #l’s biodegradation rate, it can be considered home compostable. This is shown as the “required level for domestic biodegradation” (as a dotted line) in the FIG. 3.

[0122] FIG. 3 is a graph that depicts the home biodegradation rate in percentage versus time in days for Sample #1 through Sample #5. Sample #5 which a spunbond made with 100% PBS had the lowest biodegradation rate. As explained above, a material must biodegrade and disintegrate at a certain rate at a given temperature to be considered compostable. Without wishing to be bound by theory a faster disintegration rate will contribute to a faster biodegradation rate because it provides more accessible surface for microorganisms to biodegrade a material. Spunbond material is made by bonding extruded spun fibers. These endless fiber filaments confer exceptional mechanical properties to the material but also make the material less compostable compared to wet-laid materials especially wet-laid materials containing cellulose. Furthermore, heat-seal fibers used in a wet-laid are short-cut fibers which most likely will disintegrate faster compared to the endless filaments present in a spunbond.

[0123] Samples #2, #3 and #4 do not biodegrade to more than around 70%. The above data shows that samples containing polylactic acid (PLA), polybutylene succinate (PBS) and a blend of polylactic acid (PLA) and polycaprolactone (PCL) fibers even in a wet-laid material containing more than 70 wt% of cellulose fibers do not biodegrade more than 70%. These materials are thus not home compostable.Example 2

[0124] This example is conducted to demonstrate that the addition of poly (butylene succinate-co-adipate) (PBSA) polymer improves biodegradability properties when compared with previously tested polymers above such as PBS, PLA or a blend of PLA with PCL. The samples are listed below along with their compositions.

[0125] Sample #6: 100 wt% cellulose fibers.

[0126] Sample #7: 70 wt% PBSA and 30 wt% of PBS filaments.

[0127] Sample #8: 50 wt% PBSA and 50 wt% of PBS filaments.

[0128] FIG. 4 is a graph that depicts the home biodegradation rate in percentage versus time in days for Sample #6 through Sample #8.

[0129] The different samples were then subjected to a home compostability test as detailed above.

[0130] FIG. 4 shows that the sample containing a 70 / 30 PBSA / PBS blend achieves the required biodegradation in less than 100 days. The sample containing 50 / 50 PBSA / PBS blend achieves a biodegradation rate of around 80%.Example 3

[0131] A single-ply wet-laid non-woven sample as represented in FIG. IB was prepared by using 84.5 wt% of cellulosic fibers and 15.5 wt% of heat-seal composition relative to the total weight of the non-woven. The heat-seal composition comprises supplementary heat-sealable fibers that are short-cut PLA fibers (in an amount 50 wt% of the heat-seal composition) and PBSA / PBS mono-component short cut fibers in an amount of 50 wt% of the heat-seal composition. The fibers 11 of the heat-seal composition comprise 70 wt% PBSA and 30 wt% PBS. Accordingly, the single ply wet-laid non-woven sample comprises 84.5 wt% cellulosic fibers 10, 7.75 wt% heat-seal composition in the form of fibers 11 and 7.75 wt% of supplementary heat-sealable fibers 12, based on the total weight of the non-woven.

[0132] The sample is subjected to a home compostability test the FIG. 5 below depicts the home biodegradation rate. The sample reached a relative biodegradation rate of around 93% relative to the total amount of biodegradable material present in the non-woven. FIG. 5 shows the biodegradation rate for a comparative sample that contains only cellulose (which shows a total biodegradation rate of 90%). The inventive non-woven shows a biodegradation rate of about 85%, which represents 93% of the total biodegradable material in the non-woven by weight.

[0133] The inventive sample has a dry heat seal strength of 0.37 Newtons (N). The dry peel strength is measured as follows. Two heat-seal sides of the material are attached using heated clamps at 180°C with a force of 2 bars for 1.5 seconds. The resistance to peel is then measured by applying a peel force at a rate of 200 mm / min on a test piece of 15 mm width. A non-woven material without the heat-sealable fibers disclosed herein (e.g., a 100% cellulosic material) would have a dry heat seal strength of 0.00 N and would not be heat sealable.

[0134] The data shown in the FIGS. 3 through 5 indicate that the addition of PBSA to PBS produces a non-woven with the desired properties for home compostability.

[0135] With reference to FIGs. 2A and 2B, the non-woven 1 is a two-ply non-woven. Said non-woven 1 comprises the heat-seal composition in the form of fibers 11 , and optionallysupplementary heat-sealable fibers 12, in an amount of 15 wt% of the total weight of the nonwoven 1 and 85 wt% cellulosic fibers 10 of the total weight of the non-woven 1. According to these examples, the fibers 11 of the heat-seal composition are short cut mono-component fibers of PBSA / PBS, comprising 70 wt% PBSA and 30 wt% PBS. In the case of FIG. 2B, the supplementary heat-sealable fibers 12 are PLA fibers and the heat-seal composition comprises 50wt% fibers 11 of the heat-seal composition made of PBSA / PBS (70:30) and 50 wt% supplementary heat-sealable fibers 12. Said two-plies non-woven has a dry heat seal strength comprised between 0.85 N and 1 .2 N. The dry heat seal strength is measured as follows: two heat-seal sides of the material are attached using heated clamps at 180°C with a force of 2 bars for 0.5 second.

[0136] While the present disclosure has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof.

[0137] Therefore, it is intended that the present disclosure not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this present disclosure, but that the present disclosure will include all embodiments falling within the scope of the claims. Additional modifications, changes, and substitutions are intended in the foregoing disclosure. Since many changes could be made in the above construction and many widely different embodiments of this disclosure could be made without departing from the scope thereof, it is intended that all matter contained in the drawings and specification shall be interpreted as illustrative and not in a limiting sense. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the disclosure.

Claims

CLAIMSWhat is claimed is:

1. A non-woven (1), the non-woven (1) comprising: a heat-seal composition comprising:55 to 75 wt% of poly(butylene succinate-co-adipate); and25 to 45 wt% of polybutylene succinate, based on a total weight of the heat seal composition, where the non-woven (1) is home compostable.

2. The non-woven (1) according to claim 1, where the heat-seal composition is in fiber form (1 1) or in the form of a dispersion (14).

3. The non-woven (1) according to any one of the preceding claims, wherein the non-woven (1) is a wet-laid non-woven.

4. The non-woven (1) according to any one of the preceding claims, wherein the non-woven (1) has a basis weight of 10 to 100 g / m2.

5. The non-woven (1) according to any one of the foregoing claims, wherein the non-woven (1) is a single ply.

6. The non-woven (1) according to any one of claims 1 to 4, wherein the nonwoven (1) comprises at least two plies (20, 21), preferably the heat-seal composition is present in an exterior ply of the non-woven (1).

7. The non-woven (1) according to any one of the foregoing claims, wherein the non-woven (1) comprises the heat-seal composition in an amount of 1 to 25 wt%, based on a total weight of the non-woven (1).

8. The non-woven (1) according to any one of the foregoing claims, wherein the non-woven (1) comprises 75 to 99 wt% of cellulosic fibers (10), based on a total weight of the non-woven (1).

9. The non-woven (1) according to any one of the foregoing claims, wherein the non-woven (1) further comprises supplementary heat-sealable fibers (12) selected from polylactic acid, polylactic acid blended with another compostable polymer such as polylactic acid-polyhydroxyalkanoate blends, polylactic acid-polycaprolactone blends, such that the total polylactic acid content is in an amount of less than 12 wt% preferably less than 10 wt% based on a total weight of the non-woven.

10. The non-woven (1 ) according to claim 9, wherein the supplementary heat- sealable fibers (12) have a length between 1 and 20 mm preferably between 2 and 10 mm and / or a linear density between 0.1 and 5 dtex.

11. The non-woven (1) according to any one of the foregoing claims 2 to 10, wherein the fibers (11) of the heat-seal composition have a length between 1 and 20 mm preferably between 2 and 10 mm and / or a linear density between 0.1 and 5 dtex.

12. The non-woven (1) according to any one of the foregoing claims, wherein the heat-seal composition has a melting temperature of at least 100°C.

13. The non-woven (1) according to any one of claims 2 to 12, wherein the fibers (11) of the heat-seal composition are mono-component fibers.

14. The non-woven (1) according to any one of claims 2 to 13, wherein the fibers (11) of the heat-seal composition are bi-component fibers.

15. The non-woven (1) according to any one of claims 2 to 14, wherein the fibers (11) of the heat-seal composition comprise a blend of poly (butylene succinate-co-adipate) and polybutylene succinate.

16. The non-woven (1) according to any one of claims 2 to 15, wherein the fibers (11) of the heat-seal composition comprise polybutylene succinate fibers and poly (butylene succinate-co-adipate) fibers and where the polybutylene succinate fibers are devoid of poly(butylene succinate-co-adipate) and where the poly(butylene succinate-co-adipate) fibers are devoid of polybutylene succinate.

17. A heat-seal article comprising the non-woven (1) according to any one of the foregoing claims.

18. The heat-seal article according to claim 17, where the heat-seal article is a tea bag, a coffee bag, an herbal sachet, a food packaging article, a medical packaging article, a horticultural wrapping paper, a cook-in bag or a bag for particulate liquid cleansing agents.

19. A method of manufacturing a non-woven (1) according to any one of the foregoing claims, wherein the method comprises the steps of:(a) providing a slurry comprising cellulosic fibers (10);(b) forming a non-woven wet-laid on a forming wire;(c) at least partially drying the non-woven wet-laid; the method further comprises a step of providing a heat-seal composition, said heatseal composition comprises, 55 to 75 wt% of poly(butylene succinate-co-adipate) and 25 to 45 wt% of polybutylene succinate, based on a total weight of the heat-seal composition.

20. The method according to claim 19, wherein the heat-seal composition is in the form of a dispersion (14) and wherein it is applied to the non-woven wet-laid after step (c).

21. The method according to claim 19, wherein the heat-seal composition is in the form of fibers (11) and wherein it is provided to the slurry before step (b).

22. The method according to claim 21, wherein the fibers (11) of the heat-seal composition are hicomponent fibers.

23. The method according to claim 21, wherein the fibers (11) of the heat-seal composition are monocomponent fibers.

24. The method according to any one of claims 21 to 23, wherein at least a portion of the fibers (11) of the heat-seal composition are produced by the following steps: melting the poly(butylene succinate-co-adipate) and the polybutylene succinate; spinning the melted poly(butylene succinate-co-adipate) and the polybutylene succinate to form filaments; cutting the filaments to form the fibers (11) of the heat-seal composition.

25. The method according to claim 24, wherein at least a portion of the poly(butylene succinate-co-adipate) and the polybutylene succinate are melt-blended before the spinning step.

26. The method according to any one of claims 21 to 25, wherein the fibers (11) of the heat-seal composition have a length between 1 and 20 mm, preferably between 2 and 10 mm and / or a linear density between 0. 1 and 5 dtex.

27. The method of any one of claims 19 to 26, where the non-woven (1) comprises the heat seal composition in an amount of 1 to 25 wt% based on the total weight of the non-woven (1).

28. The method according to any one of claims 19 to 27, wherein the non-woven (1) comprises cellulosic fibers (10) in an amount of 75 to 99 wt%, based on the total weight of the non-woven (1).

29. The method according to any one of claims 19 to 28, wherein the method further comprises a step of providing supplementary heat-sealable fibers (12) to the slurry, said step of providing supplementary heat-sealable fibers (12) to the slurry being performed prior to step (b).

30. The method according to claim 29, wherein the supplementary heat-sealable fibers (12) are selected from polylactic acid, polylactic acid blended with another compostable polymer such as polylactic acid-polyhydroxyalkanoate blends, polylactic acid- polycaprolactone blends, such that the total polylactic acid content is in an amount of less than 12 wt%, preferably less than 10 wt%, based on the total weight of the non-woven (1).

31. The method according to any one of claims 29 to 30, wherein the supplementary heat-sealable fibers (12) have a length between 1 and 20 mm, preferably between 2 and 10 mm and / or a linear density between 0.1 and 5 dtex.

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