Fabric

Abstract

A process for producing a thermoformable and bondable fabric in which the fabric is biodegradable and/or compostable. The process comprises extruding a polymeric blend to form a plurality of filaments, the filaments collectively comprising the fabric.

Claims

1. A process for producing a thermoformable and bondable fabric, the fabric being biodegradable and/or compostable, the process comprising: extruding to form a plurality of bi-component filaments comprising one or two polymeric blends, the filaments collectively comprising the fabric, wherein the one or two polymeric blends collectively comprise a first polylactic acid and a second polylactic acid, wherein the first polylactic acid (a) comprises a greater proportion of D-configuration lactic acid units to L-configuration lactic acid units than in the second polylactic acid (b) and wherein the melting point of the first polylactic acid is lower than the melting point of the second polylactic acid.

2. The process according to claim 1, wherein said process is configured to yield a crystallinity in the plurality of filaments of about 30 to about 45%.

3. The process according to claim 1, wherein the one or two polymeric blends comprises 3 to about 12% polybutylene succinate, based on the total weight of the blend.

4. The process according to claim 1, wherein the one or two polymeric blends collectively comprise: polybutylenesuccinate, polybutylene succinate-co-adipate, polybutylene adipate-co-terephthalate, polyhydroxyalkanoate or polycaprolactone.

5. The process according to claim 1, wherein said filaments are exposed to an extrusion cabin pressure of about 1000 to about 5000 Pa.

6. The process according to claim 1, further comprising hydro-entanglement, wherein said hydro-entanglement comprises one or more water jets configured to project water at a pressure of about 7,000 to about 12,500 kPa.

7. The process according to claim 6, further comprising an infrared heating step downstream of said hydro-entanglement.

8. The process according to claim 1, wherein: (a) the first polylactic acid comprises up to about 5% D-configured lactic acid units (based on the total number of lactic acid units in the polylactic acid); and/or (b) the second polylactic acid comprises up to about 1% D-configured lactic acid units (based on the total number of lactic acid units in the polylactic acid).

9. The process according to claim 1, wherein the process employs one polymeric blend and wherein the blend comprises about 5 to about 15% of the first polylactic acid (a) and about 78 to about 88% of the second polylactic acid (b), based on the total weight of the blend.

10. The process according to claim 1, wherein there is one polymeric blend and both components in the bi-component filaments comprise the same polymeric blend.

11. The process according to claim 1, wherein there are two polymeric blends and each component in the bi-component filaments comprises a different polymeric blend.

12. The process according to claim 1, wherein one component in the bi-component filaments comprises a polymeric blend comprising said second polylactic acid (b) and wherein the other component in the bi-component filaments comprises polymeric blend comprising said first polylactic acid (a).

13. The process according to claim 1, wherein said process is configured to yield filaments having a core and sheath configuration, wherein the core comprises a polymeric blend comprising said second polylactic acid (b) and wherein the sheath comprises a polymeric blend comprising said first polylactic acid (a).

14. The process according to claim 10, wherein said process is configured to yield filaments having a core comprising about 60 to about 90% of a filament, on a weight basis.

15. The process according to claim 13, wherein the polymeric blend of the sheath has a lower melting point than the polymeric blend of the core.

16. The process according to claim 1, wherein said process employs a diffuser exit gap of between about 100 to 150 mm.

17. The process according to claim 1, wherein said process employs a line speed of about 15 to 50 metres per minute.

18. The process according to claim 1, wherein said process employs a presser roller configured to press the fabric with a pressure of between about 100 kPa and about 400 kPa.

19. The process according to claim 1, wherein said process employs a presser roller heated to a temperature of about 40 to about 80° C.

20. The process according to claim 1, wherein said process employs an air volume ratio of about 3 to about 7.5.

21. The process according to claim 1, wherein said process comprises spunbonding, comprising a die.

22. The process according to claim 1, comprising drawing the filaments; wherein said filaments are at a temperature at or above a glass transition temperature during said drawing.

23. The process according to claim 1, wherein a fluid is provided downstream of the die, said flow of gas being configured disperse filaments in all directions to increase planar isotropy of filament orientation.

24. The process according to claim 1, further comprising laying the filaments onto a surface.

25. The process according to claim 1, further comprising forming the fabric to a desired shape by thermoforming using a thermoforming mold, wherein the thermoforming mold is at a temperature of about 70° C. to 140° C.

26. The process according to claim 25, wherein the fabric is at a defined temperature above the glass transition temperature during said forming.

27. The process according to claim 26, wherein said defined temperature is achieved by directing a flow of gas at the fabric.

Description

(1) The invention will now be described with reference to the following non-limiting figures and examples in which:

(2) FIG. 1 shows a schematic for a spun-bonding extrusion process according to the present invention.

(3) FIG. 2 shows a schematic for a melt blowing extrusion process according to the present invention.

(4) FIG. 3 shows the DSC spectra of samples X, Y and Z.

(5) A typical extrusion process for producing a fabric in accordance with the present invention is described below, with reference to FIGS. 1 and 2.

(6) FIGS. 1 and 2 each comprise an extruder 1, fluidly connected to an extrusion die block 3 for producing a filament of extruded material. The material is directed to a conveyer belt 5 for consolidation and thereafter conveyed away for downstream processing.

(7) The extruder 1 comprises a cylindrical barrel fitted with a threaded cylindrical screw co-axially disposed within and rotatable with respect to the barrel (barrel and screw not shown in the schematic drawings). The function of the screw is to force molten material through the barrel and out of orifices 7 in the die block 3. Material may be metered into the extruder. Molten material flows through grooves in the threaded screw when being forced through the barrel.

(8) The screw is driven by a motor, and the speed of rotation of the screw can be controlled by adjustment of the motor operating settings. The speed of rotation of the screw can be adjusted to tune the pressure at which the molten material is pumped (the “extruder pressure”).

(9) It is not necessary to mix materials (e.g. in the form of powder, pellets, or liquids) prior to extrusion; transit through the extruder 1 will result in sufficient mixture. In the case of extruding a polymeric blend, therefore, it will be appreciated that individual components of the blend (e.g. the individual polymers) may be added separately to the extruder feed zone 9 as discrete powder/pellets with no prior mixture (each individual particle of powder or each individual pellet corresponding to a single component polymer). The action of the screw then causes the components to become mixed as the materials pass towards the die. Alternatively, the components may be mixed prior to adding to the extruder 1, if desired, and extruded together.

(10) The extruder 1 is divided into five distinct zones, namely a first “feed zone” 9, and four further downstream zones (Z1-Z4; zones Z1-Z4 not depicted) within and leading along the barrel successively towards the die block. The materials for adding to the feed zone and the feed zone itself are typically held at a relatively low temperature. The zones may be held at successively higher temperatures from the feed zone to the final zone (Z4), to provide gradual heating of the mixture. The final zone, Z4, may be at a temperature equivalent to the die block 3.

(11) The molten blend is then pumped through the die block 3 by means of a melt pump (not depicted), which may also be held at the same temperature of the die and Z4, to ensure temperature consistency and/or consistency of polymer output. The molten material forms liquid jets of material upon exiting orifices in the die block 3. The pressure of the molten polymer just prior to leaving as jets can be measured (the so-called “die pressure”).

(12) The flow rate of the molten polymer can be calculated from the amount of molten liquid leaving the die block 3 and the throughput can be calculated from the weight of polymer leaving the die block 3. The throughput can be quoted on a weight per holes per minute basis and equivalent throughput on a kilogram per hour basis, given a 1.1 meter die with a fixed number of orifices 7 per meter.

(13) The jets and downstream filaments leaving the die block 3 are thereafter laid onto a conveyer for compaction 5 and downstream processing. The filaments may be considered as a web of filaments once laid.

(14) After laying, the web is passed by a conveyer belt 5 and/or a series of rollers for finishing. The web may be compressed using one or more rollers 11 (FIG. 1 only).

(15) The fabric may be subject to calendering. Calendering involves pressing the fabric between rollers 13 (FIG. 1 only) at an elevated temperature (“calendar roll temp.”) to yield a fabric having a thickness (thickness post calendar). The fabric may also be subject to entanglement, e.g. using hydro-entanglement jets 15 (FIG. 1 only)

(16) Referring to FIG. 1, there is shown therein a spunbonding embodiment of the process of the invention. Upon exiting the die 3, the filaments are subject to drawing tensile force, causing the filaments to become elongated.

(17) The jets are cooled, causing the molten material to solidify and thereby form solid filaments of the material, the filaments corresponding to the jets. Cooling is achieved by exposing the liquid jets of material to quenching air upon exiting the die 3 (e.g. air at a “quenching temperature” sufficient to solidify the material). In the spundbonding technique illustrated, the quenching fluid is configured to cause the jets to solidify as a continuous filament leaving the die 3. Quenching is conducted in a chamber 17 (so-called “spinning chamber”) to assist in maintaining ambient conditions (e.g. temperature and pressure around the die orifices).

(18) The spinning chamber has a length (in the machine direction, through which filaments traverse upon leaving the orifices) of about 1 m to 1.5 m, width of about 1.3 m, depth of about 0.45 m and a downstream outlet gap of about 80 mm. The spinning chamber has have a first zone 19 (i.e. which filaments encounter first upon traversing the spinning chamber) in which quenching air is provided at a temperature of about 20° C. to 40° C. and a second zone 21 in which quenching and drawing air is provided at a temperature of about 15° C. to 30° C.

(19) The solidified filaments then pass from the quenching chamber 17 through a shaft 23. The shaft 23 is configured to provide a turbulent flow of air in the form of a vortex 25, causing the filaments to spread out in all directions before being lain onto the conveyer belt 5 as described above. The shaft 23 is provided with an inlet 27 (SAS gap) for permitting air flow into the shaft 23 and modifying filament spreading. The gap of the pre-diffuser exit 29 influences filament spreading as well.

(20) Referring to FIG. 2, there is shown therein a melt blowing embodiment of the process of the invention. Melt blowing is an alternative type of extrusion to spun bonding. In melt blowing, upon exiting the die 3 liquid jets of material are exposed to a high velocity hot gas flow (such as about 200° C. to 260° C.). The gas flow disrupts the liquid jet and separates sections of the jet from one another, with the result that the filaments solidifying therefrom are short, fine and may be discontinuous. The thereafter filaments fall onto the conveyer belt 5 as described above, the distance of the fall being referred to as the blow height 31.

(21) The following examples are merely illustrative examples of the invention described herein, and are not intended to be limiting upon the scope of the invention.

EXAMPLE 1

(22) A series of blends were prepared for subsequent extrusion, in accordance with the blend components listed in the table below.

(23) In the table, PLA means polylactic acid; PBS means polybutylenesuccinate; PHBV means polyhydroxyalkanoate PBAT means polybutylene adipate-co-terephthalate, and PP means polypropylene.

(24) DP316-DP319 and DP323 were produced using spunbonding, whereas the others were melt blown.

(25) TABLE-US-00003 Generic name Melt strength PLA PBS PHBV PBAT PP Talc Stearate enhancer Anti-oxidant [%] [%] [%] [%] [%] [%] [%] [%] [%] Commercial name Ingeo Ingeo Bionelle Enpol GSPIa Ecomann Ecoflex Braskem Magsil Atmer Paraloid TA-45-08 6252D 6100 1020MD G4560J FZ71PD 10020EM F1200 CP380G extrafine 103 250BPMS MA13 DP249 33 64.5 1 1.5 DP250 49 48.5 1 1.5 DP251 64.5 33 1 1.5 DP252 80 18.75 1 0.25 DP253 0 49.25 49.25 1 0.5 DP254 0 73.5 25 1 0.5 DP256 90 8 1 1 DP269 68.25 29.25 1 1.5 DP285 38 60 1 1 DP286 30 68 1 1 DP293 30 68 1 1 DP294 38 60 1 1 DP296 38 60 1 1 DP307 18 80 1 1 DP310 11.13 86.67 1.1 1.1 DP311 36.1 57 5 0.95 0.95 DP314 11.11 81.67 5 1.11 1.11 DP315 11.11 76.67 10 1.11 1.11 DP316 11.11 86.67 1.11 1.11 DP317 11.13 81.67 5 1.1 1.1 DP318 11.4 86.6 2 DP319 23 75 1 1 DP323a 100 0 DP323b 98 2

EXAMPLE 2

(26) A series of fabrics were extruded in accordance with the typical melt blow extrusion technique set out above, adopting the processing parameters set out in the table below.

(27) TABLE-US-00004 DP286 DP285 DP294 DP296 Die pressure (bar) 45 62 24 39 Melt temp (° C.) 219 196 215 Air knife temp at 240 240 240 270 head (° C.) Air knife pressure (bar) 0.09 0.11 0.09 0.12 Air knife flow 1045 1105 1105 1175 rate (L/min) Blow height (cm) 17.5 28 28 40 Fabric weight (gsm) 150 175 175 172 Filament diam range (μm) 18-22 21-31 21-31 25 Spinneret hole diam (mm) 0.13 0.13 0.13 0.13 Spinneret hole 0.65 0.65 0.65 0.65 length (mm) Calendar roll temp (° C.) 87 83 84.5 83 Thickness post 0.32 0.4 0.34 0.38 calender (mm) Holes/in (81 in 0.1 m) 18.7 Throughput (g/hole/min) 0.163 0.190123 0.190123

(28) Tests were run on a lab scale melt blown line (approximate line width 15 cm). Used at Fibre Extrusion Technologies (Leeds).

EXAMPLE 3

(29) A further series of fabrics were extruded in accordance with the typical melt blow extrusion technique set out above, adopting the processing parameters set out in the table below. Tests were run on a Reicofil MB melt-blown line: a 1.1 m wide model commercial line, used at The Non-wovens Institute, North Carolina Stat Uni, Raleigh.

(30) TABLE-US-00005 Die Additional (holes per Die Die Air knife Air knife Quench air Blow Basis resin, inch/diamete, melt T pressure temp flow rate temperature height Throughput weight OPP Resin mm) (° C.) (bar) (° C.) (m3/hour) (° C.) (mm) (kg/hour) (g/m.sup.2) (% w/w) DP294 35/0.4 255 8 273 800 12.2 221 58 175 DP294 35/0.4 254 8 274 900 12.1 300 58 175 DP294 35/0.4 255 8 272 950 11.2 501 58 177 DP285 35/0.3 233 39 255 800 25 230 56 172 DP285 35/0.3 233 28 255 799 25 230 46 142 DP296 20/0.6 254 14 324 500 12 250 52 224 DP296 20/0.6 254 13 328 500 12 300 52 223 DP296 35/0.4 264 7 285 302 12 350 27 202 DP296 35/0.4 264 7 285 300 11.9 250 27 201 DP310 35/0.4 286 18 284 400 25 200 42 180 DP317 35/0.4 287 24 290 400 25.1 200 43 188 DP310 35/0.4 286 20 290 401 24.8 200 43 183 DP296 35/0.4 286 14 292 400 12 200 46 200 5 DP297 35/0.4 285 21 285 399 12 200 60 101 DP296 35/0.4 287 14 294 301 12 300 46 202 DP296 35/0.4 286 14 296 300 12 250 46 201 DP296 35/0.4 286 15 290 400 11.9 200 43 202 7

(31) OPP (oriented polypropylene) resin used was Braskem 360H grade.

EXAMPLE 4

(32) A further series of fabrics were extruded in accordance with the typical spunbond extrusion technique set out above, adopting the processing parameters set out in the table below. Tests were run on a Reicofil 4 spun-bond line, STFI (Saxony Textile Institute), Chemnitz, Germany.

(33) TABLE-US-00006 trial no. 570 571 572 573 574 575 576 577 578 579 Resin C1: PLA 6100 D (core) x x x x x x x x x x Resin C2: PLA 6752 D x x x x x x x x x x (sheath) auxiliary component C1/C2: 5 5 5 8 8 7 7 7 7 7 GS Pla 71PD [%] (core/sheath) throughput per hole 0.7 0.7 0.78 0.78 0.78 0.78 0.78 0.78 0.78 0.78 [g/min * hole] fabric weight (SET) [gsm] 125 110 125 125 125 110 135 125 125 125 throughput ratio C1:C2 80:20 80:20 80:20 80:20 80:20 80:20 80:20 80:20 80:20 80:20 melt temperature die C1 [° C.] 233 235 235 235 234 234 235 234 234 234 melt temperature die C2 [° C.] 234 234 234 234 235 233 235 234 235 235 melt pressure die C1 [bar] 122 121 130 127 128 129 130 132 132 132 melt pressure die C2 [bar] 108 105 114 110 110 114 112 115 114 113 cabin pressure (SET) [Pa] 6000 6000 4000 4000 4000 4000 4000 4000 4000 4000 process air volume Q1 1551 1254 927 693 768 932 762 783 940 875 [m.sup.3/h] process air volume Q2 6918 6858 5781 5716 5582 5716 5521 5838 5616 5816 [m.sup.3/h] process air temperature Q1 40 40 40 40 40 40 40 40 40 40 [° C.] process air temperature Q2 20 20 20 20 20 20 20 20 20 20 [° C.] SAS gap (exit) [mm] 20 20 20 20 20 20 20 20 20 20 gap diffusor exit [mm] 119 119 119 119 142 142 142 142 142 142 filament fineness [den] 4.55 — 5.99 — — — — — — — filament diameter [μm] - 22.78 — 26.14 — — — — — — — Filament fabric weight [gsm] 126.3 108.1 122 121.2 120.5 106.7 121.3 126.1 132.5 121.6 trial no. 946 947 948 949 950 951 952 953 954 955 Resin C1: PLA x x x x x x x x x x 6100 D (core) Resin C2: PLA x x x x x x x x x x 6752 D (sheath) auxiliary 7 7 7 7 7 7 7 7 7 8 component C1/C2: GS Pla 71PD [%] (core/sheath) throughput per 2.02 2.02 2.02 2.02 2.02 2.02 2.02 2.02 2.02 2.02 hole [g/min * hole] fabric weight 140 140 140 140 140 140 140 140 140 140 (SET) [gsm] throughput ratio 80:20 80:20 80:20 80:20 80:20 80:20 80:20 80:20 80:20 80:20 C1:C2 melt temperature 233 234 234 233 234 234 233 233 234 233 die C1 [° C.] melt temperature 234 235 235 233 234 234 233 233 234 234 die C2 [° C.] melt pressure die 115 114 115 117 114 114 118 116 116 118 C1 [bar] melt pressure die 106 105 105 107 105 103 106 104 103 104 C2 [bar] cabin pressure 4000 4000 4000 4000 4000 4000 4000 3500 3500 3500 (SET) [Pa] process air 1034 998 933 920 913 961 1020 948 932 948 volume Q1 [m.sup.3/h] process air 5911 5859 5920 5560 5968 5751 6150 5499 5456 8316 volume Q2 [m.sup.3/h] process air 40 40 40 40 30 25 25 25 25 25 temperature Q1 [° C.] process air 20 20 20 20 20 15 15 15 15 20 temperature Q2 [° C.] SAS gap (exit) 20 20 20 20 20 20 22 20 20 20 [mm] gap diffusor exit 89 99 111 142 108 108 108 111 99 99 [mm] filament fineness — [den] filament diameter 25.77 27.67 28.14 28.41 27.04 28.68 27.43 28.15 29.49 — [μm] - Filament fabric weight 139.1 139.9 139.1 132.7 138.3 139.3 140.4 144.3 140.8 144.3 [gsm] trial no. 196 197 198 199 200 Resin C1: PLA — — — — — 6100 D (core) Resin C2: PLA x x x x x 6752 D (sheath) auxiliary 7 7 7 7 7 component C1/C2: GS Pla 71PD [%] (core/sheath) throughput per 0.93 0.93 0.93 0.93 0.93 hole [g/min * hole] fabric weight 140 140 140 120 120 (SET) [gsm] throughput ratio 69:31 69:31 69:31 69:31 69:31 C1:C2 melt temperature 236 236 236 236 236 die C1 [° C.] melt temperature 239 239 239 239 239 die C2 [° C.] melt pressure die 86 86 86 87 87 C1 [bar] melt pressure die 70 70 70 71 71 C2 [bar] cabin pressure 3500 3500 3500 3500 3000 (SET) [Pa] process air 1304 1204 1513 1100 927 volume Q1 [m.sup.3/h] process air 5321 5191 5226 5230 4944 volume Q2 [m.sup.3/h] process air 35 35 35 35 35 temperature Q1 [° C.] process air 25 25 25 25 25 temperature Q2 [° C.] SAS gap (exit) 20 20 20 20 20 [mm] gap diffusor exit 111 131 142 142 142 [mm] filament fineness 3.29 — — 3.03 3.69 [den] filament diameter [μm] - Filament fabric weight 130 126.3 128.5 119.7 117.3 [gsm] trial no. 755 756 757 758 759 760 761 762 763 764 765 Resin C1: PLA x x x x x x x x x x x 6100 D (core) Resin C2: PLA — — — — — — — — — — — 6100 D (sheath) Resin C1: PLA — — — — — — — — — — — 6752 D (core) Resin C2: PLA x x x x x x x x x x x 6752 D (sheath) auxiliary 7 7 7 7 7 7 7 7 7 7 7 component C1/C2: GS Pla 71PD [%] (core/sheath) throughput per 2.02 2.02 2.02 2.02 2.02 2.02 2.02 2.02 2.02 2.02 2.02 hole [g/min * hole] fabric weight 125 125 125 150 130 130 130 130 130 130 130 (SET) [gsm] throughput ratio 80:20 80:20 80:20 80:20 80:20 80:20 80:20 80:20 80:20 80:20 80:20 C1:C2 melt 233 234 234 234 234 235 234 235 235 235 235 temperature die C1 [° C.] melt 234 235 235 235 235 235 235 235 235 235 235 temperature die C2 [° C.] melt pressure 128 127 127 127 127 127 124 122 122 122 122 die C1 [bar] melt pressure 110 109 109 110 110 110 112 111 110 110 111 die C2 [bar] cabin pressure 4000 4000 4000 4000 4000 5000 4000 4000 4000 4500 4500 (SET) [Pa] process air 839 729 1065 987 927 1202 1014 1087 1165 1127 1244 volume Q1 [m.sup.3/h] process air 5399 5538 5751 5773 5734 6293 5681 5712 5668 5964 5972 volume Q2 [m.sup.3/h] process air 40 40 40 40 40 40 30 30 40 40 40 temperature Q1 [° C.] process air 20 20 20 20 20 20 20 20 20 20 20 temperature Q2 [° C.] SAS gap (exit) 20 20 20 20 20 20 20 20 20 20 20 [mm] gap pre-diffusor 20 20 24 24 24 24 24 24 24 24 24 (exit) [mm] filament fineness 6.23 — — — — 5.33 5.64 — — 5.58 — [den] fabric weight 138.6 142.7 138.8 146.2 129.7 139.5 139.1 147.6 148 129.9 130.2 [gsm] trial no. 766 767 768 769 770 771 772 773 774 Resin C1: PLA x x x x x x x x x 6100 D (core) Resin C2: PLA — x x x x x x x x 6100 D (sheath) Resin C1: PLA — — — — — — — — — 6752 D (core) Resin C2: PLA x — — — — — — — — 6752 D (sheath) auxiliary 7 7 7 7 7 7 7 7 7 component C1/C2: GS Pla 71PD [%] (core/sheath) throughput per 2.02 2.02 2.02 2.02 2.02 2.02 2.02 2.02 2.02 hole [g/min * hole] fabric weight 130 140 130 140 130 140 130 140 130 (SET) [gsm] throughput 80:20 80:20 80:20 80:20 80:20 80:20 80:20 80:20 80:20 ratio C1:C2 melt 235 233 234 234 235 235 235 235 235 temperature die C1 [° C.] melt 235 232 233 233 234 234 234 234 234 temperature die C2 [° C.] melt pressure 123 119 116 116 115 115 114 114 114 die C1 [bar] melt pressure 111 95 93 93 91 91 91 91 91 die C2 [bar] cabin pressure 4500 4500 4500 4500 4500 4500 4500 4000 4000 (SET) [Pa] process air 1124 1431 1360 975 1021 1001 1042 935 799 volume Q1 [m.sup.3/h] process air 5985 5942 6072 6055 5985 5985 6059 5747 5773 volume Q2 [m.sup.3/h] process air 40 40 40 40 40 40 40 40 40 temperature Q1 [° C.] process air 20 20 20 20 20 20 20 20 20 temperature Q2 [° C.] SAS gap (exit) 20 20 20 20 20 20 20 20 20 [mm] gap pre- 24 24 24 24 24 24 24 24 24 diffusor (exit) [mm] filament — 6.01 — — — — — 5.99 — fineness [den] fabric weight 129.4 142.3 129.9 140.8 130.9 138.1 129.8 137.3 130.3 [gsm] trial no. 775 776 777 778 779 780 781 782 783 784 Resin C1: PLA x x x x x x — — x x 6100 D (core) Resin C2: PLA x x x x x x — — — — 6100 D (sheath) Resin C1: PLA — — — — — — x x — — 6752 D (core) Resin C2: PLA — — — — — — x x x x 6752 D (sheath) auxiliary 7 7 7 7 7 7 7 7 8 8 component C1/C2: GS Pla 71PD [%] (core/sheath) throughput per 2.02 2.02 2.02 2.02 2.02 2.02 2.02 2.02 2.02 2.02 hole [g/min * hole] fabric weight 140 130 140 130 140 140 140 140 140 140 (SET) [gsm] throughput ratio 80:20 80:20 80:20 80:20 80:20 80:20 66:34 66:34 80:20 80:20 C1:C2 melt 235 235 235 235 235 235 247 247 236 236 temperature die C1 [° C.] melt 234 234 234 234 234 234 249 249 239 238 temperature die C2 [° C.] melt pressure 115 114 114 115 116 115 122 121 119 120 die C1 [bar] melt pressure 91 90 90 91 91 90 119 118 109 109 die C2 [bar] cabin pressure 4000 4000 5000 5000 5000 5500 6000 6000 4000 4000 (SET) [Pa] process air 932 832 1095 1065 1019 1170 1228 1280 1100 1088 volume Q1 [m.sup.3/h] process air 5751 5738 6324 6359 6324 6593 6866 6905 5994 5707 volume Q2 [m.sup.3/h] process air 40 40 40 40 40 40 40 40 40 40 temperature Q1 [° C.] process air 20 20 20 20 20 20 20 20 20 20 temperature Q2 [° C.] SAS gap (exit) 20 20 20 20 20 20 20 20 20 20 [mm] gap pre-diffusor 24 24 24 24 24 24 24 24 24 24 (exit) [mm] filament fineness — — 5.27 — — 5.22 — 4.92 — — [den] fabric weight 138.2 129.6 138.8 128.9 139.2 139 147.1 137.7 139.6 140.3 [gsm]

EXAMPLE 5

(34) FIG. 3 shows DSC spectra of samples X (solid line), Y (delineated with squares) and Z (delineated with triangles). The DSC spectra show a marked glass transition temperature of about 60° C. for sample Z, with a similar, but less marked, glass transition for samples X and Y.

(35) The DSC spectra also show a crystallisation peak at around 80° C. for sample Z, with a smaller crystallisation peak at the same temperature for fabric X and an even smaller crystallisation peak for fabric Y. This indicates that sample Y is more crystalline than sample X, which is more crystalline than sample Z.

(36) The DSC spectra also show a melting transition at around 175° C. for each sample.

EXAMPLE 6

(37) Samples were subject to a coffee brewing test by brewing 284 ml (10 oz) coffee in a Keurig 2.0 brewing machine. The machine employed a coffee pod comprising a filter prepared from single-layer fabrics produced in accordance with Example 2 above and having the properties in the table below.

(38) After brewing, the coffee was filtered through a 1.0 μm filter and the residue (“sediments”) were collected, dried for 24 hours at 23° C. in an atmosphere of about 50% relative humidity and weighed. The data illustrate that finer filament fabrics (smaller filament diameters), as produced by adjusting extrusion parameters as described above, give finer filtration and thereby lower sediments. The filtration of the fabric can be tailored to the coffee roaster's requirements.

(39) TABLE-US-00007 Filament Basis weight diameter Sediments Sample Extrusion Bonding Average cv Average cv Average cv ID Process process (gsm) (%) (μm) (%) (g) (%) 579 Spunbond Hydroentangling - 136.4 9.8 29.9 μm 13.4 0.276 39.5 Bico 953 Spunbond Hydroentangling - 151.0 9.7 28.3 μm 12.9 0.132 19.4 Bico 198 Spunbond Hydroentangling - 137.5 5.9 22.0 μm 10.6 0.083 18.2 Mono 16.80.42 Spunbond Calendering - 148.1 2.0 21.9 μm 9.5 0.047 3.6 Diamond roll Sample-1 Spunbond Hydroentangling - 136.4 9.8 29.9 μm 13.4 0.276 39.5 Bico Sample-2 Spunbond Hydroentangling - 151.0 9.7 28.3 μm 12.9 0.132 19.4 Bico Sample-3 Spunbond Hydroentangling - 137.5 5.9 22.0 μm 10.6 0.083 18.2 Mono Sample-4 Spunbond Calendering - 148.1 2.0 21.9 μm 9.5 0.047 3.6 Diamond roll

(40) Where “cv” is the coefficient of variation.

EXAMPLE 7

(41) Fabrics comprising polylactic acid and polybutylenesuccinate were tested to determine resistance to shrinkage by placing in an oven heated at 165° C. for 1 minute or 10 seconds.

(42) TABLE-US-00008 Cabin % shrinkage Bonding % Pressure % crystallinity 165° C., 165° C., Fabric technique PBS (Pa) DSC 1 min 10 sec 16.80.11 Calendering 6% 2100 Pa 33.4 48.2 45.3 570 Hydro 5% 6000 Pa 35.4 27.0 13.5 408 Hydro 3% 6000 Pa 38.0 27.8 19.0 953 Hydro 7% 3500 Pa 39.0 14.5 9.8

(43) Shrinkage % is measured as areal shrinkage=[(initial fabric area−final fabric area)/initial fabric area]*100.

(44) As can be seen, fabrics with higher crystallinity had improved properties with respect to shrink resistance.

EXAMPLE 8

(45) Fabrics were prepared from bi-component filaments having a core and sheath configuration, as follows:

(46) TABLE-US-00009 Composition Composition Auxiliary component Process data core:sheath core:sheath (core/sheath) thermoforming Fabric CP (Pa) 6100D:6752D 6100D:6100D % PLA 6752D % PBS T (° C.) 953 3500 80:20 — — 7% 152-155 284 3000 — 80:20 10% PLA 6752D 7% 138-147 285 2500 — 80:20 10% PLA 6752D 7% 138-147 286 3000 — 80:20 30% PLA 6752D 7% 138-147

(47) As can be seen, filaments comprising two different polylactic acids (6100D and 6752D), wherein one of said polylactic acids (6752D) had a higher D-lactic acid content than the other component (6100D) and was present at a minor level, had improved thermoformability (were able to be thermoformed at lower temperatures).

(48) Fabrics 284, 285 and 286 were produced with the typical spunbond extrusion technique set out above, adopting the processing parameters set out in the table below. Tests were run on a Reicofil 4 spun-bond line, STFI (Saxony Textile Institute), Chemnitz, Germany.

(49) TABLE-US-00010 trial no. 284 285 286 Resin C1: PLA 6100 D (core) x x x Resin C2: PLA 6752 D (sheath) — — — Resin C2: PLA 6100 D (sheath) x x x auxiliary component C1/C2: 7 7 7 GS Pla 71PD [%] (core/sheath) auxiliary component C1/C2: 10 10 30 PLA 6752 D [%] (core/sheath) throughput per hole 1.26 1.26 1.26 [g/min * hole] fabric weight (SET) [gsm] 135 135 135 throughput ratio C1:C2 80:20 80:20 80:20 melt temperature die C1 [° C.] 232 233 233 melt temperature die C2 [° C.] 231 231 231 melt pressure die C1 [bar] 83 82 85 melt pressure die C2 [bar] 62 62 63 cabin pressure (SET) [Pa] 3000 2500 3000 process air volume Q1 [m.sup.3/h] 1033 832 897 process air volume Q2 [m.sup.3/h] 5148 4783 5095 process air temperature Q1 [° C.] 25 25 25 process air temperature Q2 [° C.] 15 15 15 SAS gap (exit) [mm] 20 20 20 gap pre-diffusor (exit) [mm] 23 23 23 filament fineness [den] 4.12 4.89 4.29 fabric weight [gsm] 135.3 132.1 136.7

(50) Those skilled in the art will recognise or be able to ascertain using no more than routine experimentation many equivalents to the specific embodiments described herein. The scope of the present embodiments described herein is not intended to be limited to the above description, but rather is as set forth in the appended claims. Those of ordinary skill in the art will appreciate that various changes and modifications to this description may be made without departing from the spirit or scope of the present invention, as defined in the following claims.