Method of making a uniform spunbond filament nonwoven web

Abstract

A method of manufacturing a nonwoven web, the method comprising: providing a spinneret, wherein the spinneret includes a pattern of guide tubes forming an extrusion region; directing only a first flow of molten propylene polymer having a first temperature to a region adjacent to a first side of the spinneret; directing only a second flow of molten propylene polymer having a second temperature to a region away from the first side of the spinneret; extruding only the first flow of molten propylene polymer through an outlet opening in the first region; extruding only the second flow of molten propylene polymer through an outlet opening in a second region; the second region being away from the first side, wherein the first region is located between the second region and the first side.

Description

Technical Field

[0001] This invention relates to a method for manufacturing nonwoven webs, and more specifically to a method for manufacturing uniform spunbond filament nonwoven webs. Background Technology

[0002] Spunbond nonwoven fabrics comprise bonded webs of continuous filaments formed by extruding a molten thermoplastic polymer from multiple fine capillaries into molten filaments. The molten filaments are quenched to at least partially solidify them, and then thinned by one or more high-speed airflows, thereby reducing their diameter. In addition to producing relatively fine filaments, the pneumatic stretching of the filaments in the spunbond process also serves to increase the crystallinity of certain polymers (such as propylene polymers), which provides increased tensile strength to the resulting filaments and webs. For example, spunbond filament nonwoven webs and methods for manufacturing thereof are disclosed in US4340563 to Appel et al., US5382400 to Pike et al., US8246898 to Conrad et al., and US8333918 to Lennon et al.

[0003] Spunbond filament nonwoven webs are commonly used in a wide range of products. This broad and diverse application stems in part from the ability of spunbond filament nonwoven webs to offer a desirable combination of properties, including strength, opacity (coverage), and a pleasant hand feel. Furthermore, spunbond filament webs are relatively inexpensive to manufacture compared to other materials with similar properties, such as conventional knitted or woven fabrics. Therefore, spunbond filament nonwoven webs have been found particularly suitable for manufacturing single-use or limited-use products; such as absorbent personal care products, wipes, protective clothing, geotextiles, and waterproof tarpaulins.

[0004] To further reduce the cost of producing spunbond filament nonwoven webs, efforts have been made to increase productivity by using higher productivity (i.e., increasing the grams of polymer per minute per pore) and by using spinnerets with higher pore density (i.e., increasing the number of filaments produced per unit area of ​​the spinneret). However, as you increase productivity, this often leads to a negative impact on one or more material properties, such as hand feel (e.g., the formation of hard spots), filament diameter, filament uniformity, opacity, and other visual properties. Additionally, operating at higher productivity often adversely affects overall process stability, such as leading to a greater incidence of filament breakage and reduced yield.

[0005] Therefore, in order to address the ongoing need to produce uniform and high-quality spunbond filament nonwoven webs at higher production rates, this invention provides an improved method for producing spunbond filament nonwoven webs that allows for increased production rates while minimizing and / or eliminating losses of desired material properties and / or process stability. Summary of the Invention

[0006] An improved method for manufacturing spunbond filament nonwoven webs is provided, the method comprising the following steps:

[0007] (i) A spinneret having opposing first and second sides is provided, and the spinneret further includes a pattern of a conduit extending through the thickness of the spinneret, the pattern of the conduit forming an extrusion region;

[0008] (ii) Heating a first stream of molten polymer to a first temperature and heating a second stream of molten polymer to a second temperature, wherein the first temperature is higher than the second temperature;

[0009] (iii) Only the first flow of molten polymer is guided through the conduit in the first zone of the spinneret to form a first curtain of molten monocomponent filament, the first zone extending the length of the extrusion zone adjacent to the first side and extending inward at least 3 cm in width;

[0010] (iv) A second flow of molten polymer is guided through a conduit in the second zone to form a second curtain of molten monocomponent filament, wherein the second zone is away from the first side such that the first zone completely separates the second zone from the first side, and further wherein the second zone extends the entire length of the extrusion zone and extends at least 3 cm in width;

[0011] (v) The first quenching airflow is directly directed onto the first curtain of the monocomponent filament to form at least partially cured quenched monocomponent filament, and further wherein the first quenching airflow continues through the first curtain of the quenched monocomponent filament to the second curtain of the monocomponent filament to form at least partially cured quenched monocomponent filament.

[0012] (vi) Pneumatically drawing rapidly cooled monocomponent filaments to reduce their diameter; and

[0013] (vii) Stretched single-component filaments are deposited on a forming surface to form a nonwoven web.

[0014] In this respect, the quenched air will be warmed to a certain degree before encountering the second curtain of the low-temperature filaments, thus achieving a more uniform white line on all extruded filaments. This drives greater uniformity in terms of the conditions experienced by all filaments, and in turn, greater uniformity and overall process stability in the resulting fibers. Attached Figure Description

[0015] Figure 1A and Figure 1B This is a schematic diagram of a spunbond filament nonwoven web manufacturing system suitable for producing spunbond filament nonwoven webs according to the present invention.

[0016] Figure 2A This is a top schematic diagram applicable to the present invention, particularly those described in Figure 1.

[0017] Figure 2B yes Figure 2A A schematic diagram of the bottom of the spinneret.

[0018] Figure 3 This is a schematic cross-sectional view of a portion of a spinneret suitable for use in conjunction with the present invention.

[0019] Figure 4A and Figure 4B This is a schematic diagram of an alternative embodiment of a spunbond filament nonwoven web manufacturing system suitable for producing spunbond filament nonwoven webs according to the present invention.

[0020] Figure 5A This is a top schematic diagram applicable to the spinnerets of the present invention, particularly those described in Figure 4.

[0021] Figure 5B yes Figure 5A A schematic diagram of the bottom of the spinneret.

[0022] Figure 6 This is a diagram of a polymer flow splitter applicable to the present invention.

[0023] Figure 7A , Figure 7B and Figure 7C This is a cross-sectional view of a polymer flow suitable for use in conjunction with the present invention. Detailed Implementation

[0024] Throughout this specification and claims, the discussion of the article and / or its individual components shall be as set forth below.

[0025] The terms “comprising,” “including,” or “having” are inclusive or open-ended and do not exclude additional unlisted elements, components, or method steps. Therefore, the terms “comprising,” “including,” or “having” cover the more restrictive terms “substantially consisting of” and “consisting of.”

[0026] The term "continuous filament" as used in this article refers to filaments formed in a substantially continuous and uninterrupted manner, having an infinite length and a high aspect ratio (length to diameter) exceeding approximately 10,000:1.

[0027] As used herein, unless otherwise expressly indicated, when used in connection with material compositions, the terms "percentage" or "%" refer to the amount by weight of a component as a percentage of the total amount.

[0028] As used herein, the term "polymer" generally includes, but is not limited to, homopolymers, copolymers such as block, graft, random and alternating copolymers, terpolymers, and their blends and modified forms. Furthermore, unless otherwise specifically limited, the term "polymer" should include all possible geometric configurations of the molecule. These configurations include, but are not limited to, isotactic, syndiotactic, and random symmetry.

[0029] As used in this article, “ethylene polymer” or “polyethylene” refers to a polymer having more than 50 mol% of units derived from ethylene.

[0030] As used in this article, “olefin polymer” or “polyolefin polymer” refers to a polymer having more than 50 mol% of units derived from olefins (including linear, branched or cyclic olefins).

[0031] As used in this article, “propylene polymer” or “polypropylene” refers to a polymer having more than 50 mol% of units derived from propylene.

[0032] As used herein, the term “nonwoven web” refers to a web of structure or material formed without the use of traditional fabric forming processes such as weaving or knitting, to produce a structure of individual filaments or threads that are entangled or interwoven but not in a recognizable repeating manner.

[0033] As used herein, the term “machine orientation” or “MD” refers to the direction of travel of the filament deposited onto the forming surface during fiber web formation.

[0034] As used in this article, the term "cross-machine direction" or "CD" refers to a direction that is substantially perpendicular to the machine direction defined above.

[0035] As used herein, “personal care products” means any and all products or articles used for personal health or hygiene, including diapers, adult incontinence clothing, absorbent pants and absorbent garments, tampons, feminine pads and linings, body wipes (e.g., baby wipes, perineal wipes, hand wipes, etc.), bibs, changing pads, bandages, and components thereof.

[0036] As used in this article, “protective articles” refers to all articles designed to protect users or equipment from contact with or exposure to external substances, including, for example, face shields, protective gowns and aprons, gloves, caps, shoe covers, equipment covers, sterile wrapping materials (e.g., for medical devices), vehicle covers, etc.

[0037] The term "melting point" as used in this article refers to the melting point measured by differential scanning calorimetry (DSC). For the purposes of this article, the maximum value of the highest temperature peak is considered the melting point of the polymer. A "peak" in this article is defined as the change in the overall slope of the DSC curve (heat flow versus temperature) from positive to negative, resulting in a maximum value without baseline shift, where the DSC curve is plotted such that an endothermic reaction will appear with a positive peak. A heating rate of 10 °C / min was used.

[0038] melt spinning process

[0039] refer to Figure 1A The diagram illustrates a system 10 adapted to manufacture nonwoven webs formed from melt-extruded, drawn filaments, such as those commonly referred to as spunbond filament nonwoven webs. In one embodiment, a desired polymer composition, typically in pellet form, is provided in a hopper 12 and fed into an extruder 14, which melts the pellets and forms an initial stream of molten polymer. A portion of the molten polymer stream is directed to a spinning assembly 30 via a conduit 16. A separate portion of the molten polymer stream is directed via a conduit 18 through an additional heating element 20, which further heats the molten polymer and further increases its temperature. A high-temperature stream of the molten polymer is then separately directed to the spinning assembly 30 via a conduit 22.

[0040] The separate streams of molten polymer (i.e., the high-temperature stream and the low-temperature stream) may have an initial temperature difference of at least about 5°C. Alternatively, the initial temperature difference between the high-temperature and low-temperature streams may be less than about 50°C. As an example, this temperature difference may be greater than about 8°C, 10°C, 12°C, 15°C, or even 18°C. As a further example, this temperature difference may be less than about 45°C, 42°C, 40°C, 38°C, 35°C, 30°C, or even 28°C. While suitable ranges will vary depending on the specific polymer, generally, to limit degradation or other undesirable effects on the polymer, molten polymers are typically not heated to temperatures above their melting point of about 150°C, 125°C, 100°C, or 75°C.

[0041] refer to Figure 1B As shown, in one embodiment, the spinning assembly 30 may include a polymer splitter 31, a distributor 32, a screen pack 33, a support plate 34, and a spinneret 35. The high-temperature and low-temperature streams of molten polymer can initially be directed into the polymer splitter, which redirects the two streams and combines them to form a single stream. However, the two streams are combined in such a way that they remain intact and distinct from each other, with a stable interface between them. The two polymer streams can be combined and directed into a single conduit so that they are arranged side-by-side in the conduit, such as... Figure 7A The A / B arrangement is shown for positioning. Various devices and methods are known to converge molten polymer streams in this striped or layered configuration. In one embodiment, a feeder block with a generally Y-shaped conduit can be used to converge two streams together to form a single unmixed composite stream.

[0042] The combined stream of the high-temperature molten polymer and the low-temperature molten polymer can then be fed into distributor 32, which distributes the molten polymer over a wider area before finally feeding it into spinneret 35. However, the distributor must maintain the integrity of the polymer / polymer interface and / or the integrity of adjacent streams in order to expand the footprint of the combined stream, so that the high-temperature molten polymer and the low-temperature molten polymer do not mix. Various suitable distributors are known in the art, including T-groove distributors, "coat hanger" distributors, and other distributors well known in the art. By way of example only, various distributors are described in US7179412 and CA2621712, granted to Wilkie et al.

[0043] Optionally, though highly preferred, below the dispenser 32 are a filter or screen 33 and a support member 34. The screen is used to filter impurities or other unwanted debris from the molten material stream to prevent fouling of the spinneret, for example, by clogging one or more capillaries in the capillary. Suitable screens may, for example, comprise one or more stacked screens with a mesh size ranging from about 50 to 350. Supporting the screen is the support member 34. Suitable support members may, for example, simply comprise a metal plate comprising a large number of high-frequency orifices extending through the metal plate.

[0044] As the composite polymer stream passes through the screen 33 and support plate 34 and is fed into the spinneret 35, the composite polymer stream is maintained in different sections. (See Figure 2 and...) Figure 3As shown, the spinneret 35 typically has fasteners such as bolts, welds, brackets, clamps, or other devices along its outermost periphery to maintain the spinneret in adjacent and fluid communication with upstream components such as perforated plates and / or screens. Bolt holes 80 and bolts 81 may be located near the periphery to secure the spinneret 35 to other components of the spinning assembly 30. A raised edge 82 may be formed on the periphery of the upper surface 81, defining a recess or groove 83 for receiving molten polymer. The spinneret includes a pattern of conduits 84 extending through the spinneret 35, through which the composite polymer stream flows via an inlet opening 86, and from the inlet opening through an associated capillary 87, and exits from an associated outlet port 89. The size of the outlet port may vary, for example having a diameter between about 0.2 mm and about 0.8 mm. The pattern of the conduits may vary in many ways and in many cases will include a series of rows of conduits extending along the CD or longitudinal sides 36, 38 of the spinneret. Adjacent rows of conduits will typically be slightly offset from each other. This invention is particularly suitable for use with spinnerets having a high density of exit ports, such as more than about 5 exit ports / cm. 2 The spinneret has an outlet port or orifice density, for example, having about 5 to about 20 outlet ports / cm. 2 Approximately 8 to 18 exit ports / cm 2 Or even approximately 10 to approximately 16 outlet ports / cm 2 The density of the spinneret.

[0045] As in Figure 2B As most clearly seen, the spinneret 58 includes a pattern of conduits 84 for guiding molten polymer through the spinneret 35 and out through the corresponding outlet port 89. The spinneret will have an extrusion region, i.e., the internal region of the spinneret including the outlet ports. The extrusion region is defined by a first extrusion edge line 92, a second extrusion edge line 93, a third extrusion edge line 94, and a fourth extrusion edge line 95. The first edge line 92 is drawn along the outer periphery of the first row of outlet ports 90A-90Z that are closest to and extend along the first longitudinal edge or quench side edge 36. Similarly, the second extrusion edge line 94 is drawn along the outer periphery of the last row of outlet ports 91A-91Z that are closest to and extend along the opposite second longitudinal edge 38. The third extrusion edge line 93 and the fourth extrusion edge line 95 are drawn along the outer periphery of the first column of outlet ports 97A-97Z and the last column of outlet ports 91A-99Z that are closest to and extend along the first transverse or MD edge 37 and the second transverse or MD edge 39. The extrusion centerline 96 of the spinneret is measured as the midpoint between the first extrusion edge line 92 and the second extrusion edge line 94. The extrusion area width, or CD width, is the distance along line 93 between the relative longitudinal extrusion lines 92 and 94, and the extrusion area length, or MD length, is the distance along extrusion line 92 between extrusion lines 93 and 95.

[0046] In this embodiment, the molten polymer is guided onto the upper surface 81 of the spinneret as different segments or strips covering different regions or zones. In this respect, only the high-temperature molten polymer is guided into the first zone A and discharged from the corresponding outlet port within the first zone A. The low-temperature polymer is the only polymer guided into the second zone B and discharged from the outlet port within the second zone B. However, it should be understood that the inlet opening located at or near the polymer-polymer interface can absorb and include portions of both the high-temperature and low-temperature polymers. However, it will be limited to combining both polymers into a single conduit and outlet port, and such filaments will consist of only a small number of filaments formed. Separate streams of molten polymer (i.e., the high-temperature stream and the low-temperature stream) can be guided into and / or extruded from the spinneret having a temperature difference of at least about 3°C. On the other hand, the temperature difference between the high-temperature stream and the low-temperature stream can be less than about 50°C. As an example, the temperature difference as the polymer enters and / or exits the spinneret can be greater than about 3°C, 5°C, 8°C, 10°C, 12°C, 15°C, or even 18°C. As a further example, the temperature difference can be less than about 45°C, 42°C, 40°C, 38°C, 35°C, 30°C, or even 28°C.

[0047] Reference Figure 2A and Figure 2BHigh-temperature polymers and low-temperature polymers are introduced and exited into different zones within the spinneret. In some embodiments, such as in a spunbond system where quenching air is directed from a single direction (i.e., a one-sided quenching system), the high-temperature polymer can be directed into a first zone A, which includes all capillary and / or outlet ports within a distance from the first extrusion edge line 92. In some embodiments, the first zone A may extend inward from the first extrusion edge line 92 by a distance equal to or greater than 3 cm, 4 cm, 5 cm, 6 cm, 7 cm, 8 cm, 9 cm, 10 cm, 12 cm, or 14 cm. Furthermore, in various embodiments including the one-sided quenching implementation, the low-temperature polymer can be introduced and exited into different second zones B, which include all capillary and / or outlet ports within a distance from the second extrusion edge line 94. In some embodiments, the second zone may extend inward from the second extrusion edge line 94 by a distance equal to or greater than 3 cm, 4 cm, 5 cm, 6 cm, 7 cm, 8 cm, 9 cm, 10 cm, 12 cm, or 14 cm. The first zone A and the second zone B can be adjacent to each other, or they can be separated by an intermediate zone. In some embodiments, multiple rows can exist between the first and second zones. The rows in the intermediate section can, for example, have capillary and outlet ports for extruding a high-temperature polymer and some capillary and outlet ports for extruding a low-temperature polymer. In this respect, the interface between the high-temperature polymer and the low-temperature polymer can be tortuous, so that although the polymer flows are different, they present a concave or convex interface.

[0048] In other implementations, reference is still made to Figure 2A and Figure 2B The high-temperature polymer can be guided into a first zone A, which extends the entire length of the extrusion zone relative to the extrusion zone and extends inward from the first extrusion edge line 92 by a distance between approximately 20%-80%, 25%-75%, 35%-65%, or 40%-55% of the width of the extrusion zone. Furthermore, the low-temperature polymer can be guided into a second zone B, which extends inward from the second extrusion edge 94 (away from the quenching air) by a distance between approximately 20%-80%, 25%-75%, 35%-65%, or 40%-55% of the width of the extrusion zone.

[0049] In some embodiments, still relating to a unilateral quenching implementation, the high-temperature polymer can be guided along the quenching edge side 36 into the upper side of the spinneret 81, entering the inlet opening 86 and the capillary corresponding to the outlet port 89, spanning the entire length of the extrusion region (i.e., extending between extrusion lines 93, 95) and extending inward to cover at least about 20%, 25%, 35%, 45%, 50%, 60%, 70%, or 80% of the outlet port 89. Furthermore, the low-temperature polymer can be guided along the opposite side 38 (away from the quenching side 36) into the upper surface 81 of the spinneret, entering the inlet opening 86 and the capillary corresponding to the outlet port 89, spanning the entire length of the extrusion region and extending inward to cover at least about 20%, 25%, 35%, 45%, 50%, 60%, 70%, or 80% of the outlet port 89.

[0050] More specifically, and referring to Figures 1 and 2, the high-temperature molten polymer is guided into a first zone A, which extends along and adjacent to the quenching edge 36, i.e., along the first longitudinal side 36 of the spinneret adjacent to the first quenching airflow 32. The high-temperature molten polymer travels downward through the corresponding rows of inlet openings 86 and capillaries 87, and is extruded through an associated outlet port 89 located along the lower side or bottom 85 of the spinneret. Thus, a first bundle or curtain 24 of extruded molten strands or filaments is formed near the quenching blower 40, such that the filaments in the first bundle 24 are first directly impacted by the quenching air 42. Simultaneously, the low-temperature molten polymer is guided into a second zone B of the spinneret 35, which extends along and adjacent to the opposite longitudinal side edge 38 away from the quenching airflow 32. The low-temperature molten polymer travels downward through the corresponding inlet openings 86 and capillaries 88, and is extruded through an associated outlet port 89 located on the bottom 85 of the spinneret 35. Therefore, a second bundle or curtain 26 of extruded filaments is formed on the far side of the quench blower 40, and these filaments are indirectly impacted by the quench air 42; that is, the filaments forming the second bundle or curtain 26 are only impacted by the quench air flow 42 after the quench air has passed through the first curtain of the filaments 25. In this respect, the quench air 42 will already be warmed to a certain extent before encountering the second curtain 26 of the filaments, and thus achieve a more uniform frosted white line on all the extruded filaments 24, 26, because the filaments farther from the quench air are less hot and require less cooling to solidify.

[0051] Various quenching air systems are known in the art and can be used in conjunction with the present invention. Quenching air can be provided by a single blower at a single temperature, or by multiple blowers at different temperatures. For example, a quenching system may include a stack of multiple quenching air chambers on one side, wherein the temperature of the air provided by the upper air chamber differs from the temperature of the air provided by the quenching air chamber located below it. The quenching air temperature will vary depending on the characteristics of the melt-spun polymer, the extrusion temperature, the quenching air velocity, the filament velocity, the filament density, and other factors known in the art. Generally, quenching air is provided at a temperature between about 5-35 °C and can be provided at a velocity of about 30-115 m / min.

[0052] Return to reference Figure 1A The quenched and solidified filaments 28 are then fed into a filament drawing unit 50 for thinning or reducing the diameter of the filaments 28. Furthermore, as is known in the art, drawing also imparts crystallinity and increases the tensile strength of the filaments for various crystalline polymers such as propylene. In an open-air system, the filament drawing unit 50 has at least two walls 54 defining an open channel through which high-speed air pneumatically draws the filaments 28 downwards from the spinneret 35 toward the forming filament 60. The filament drawing unit 50 may employ an additional blower or other components known in the art. To improve the uniform diffusion and coverage of the formed nonwoven web, a deflector plate 56 may be used to diffuse the filaments, as is known in the art. Optionally, an electrostatic charging bar (not shown) or other components may be further employed to aid in filament diffusion, web forming, and layup. Although the figures depict an open-air melt spinning system, it will be readily understood that the method of the present invention can also be used with closed-air systems and other melt spinning systems known in the art. Examples of various melt spinning systems applicable to the present invention include, but are not limited to, those described in the following documents: US4340563, US5382400, US6783722, US7037097, US7762800, US8246898, US8333918, US7017 / 0211217, US20 ...

[0053] The drawn filaments leave the bottom of the filament drawing unit 50 and deposit onto the forming fabric or thread 60. As is well known in the art, one or more vacuum devices 62 are positioned below the forming thread 60 to draw the filaments onto the forming thread 60 and form a relatively loose matt or web of filaments 61. The vacuum devices also remove suction air to prevent deflected air from interfering with the laying of the filaments and / or interfering with the matt 61 once laid onto the thread. Optionally, the matt of the filaments may be treated to impart a certain minimum level of integrity required for additional processing. Such processing may, for example, involve reinforcing the matt with a compaction roller (not shown) or by using a high-speed through-air bonding machine 64. This through-air bonding machine imparts only a minimal inter-filament bond sufficient for additional processing and finishing without significantly melting the filaments. Such bonding machines and methods are described in US5707468, granted to Arnold et al.

[0054] After formation, the nonwoven felt is ideally entangled and / or bonded to increase its overall integrity and strength. In one aspect, the felt can be hydroentangled, which involves subjecting the felt to one or more rows of fine, high-pressure water jets to fully entangle the filaments together, thereby forming a coherent nonwoven web. In other embodiments, the felt can be bonded using one or more techniques known in the art, such as by applying adhesives, pressure, heat, and / or ultrasonic energy. In some aspects, as known in the art, the felt can be patterned using a pair of bonding rollers 66, 68, wherein at least one of the rollers has a protrusion or “pin” pattern corresponding to the desired pattern of the bonding points to be imparted to the felt and form the bonded nonwoven web 63. The two mating rollers form a gap through which the felt is forced through by applying pressure and optionally heat. While suitable bonding elements can be formed without applying heat, heat is preferably used in conjunction with pressure. Bonding can be performed using a gap formed by a patterning roller and a smooth anvil roller (“pin-to-flat”) or by two mating patterning rollers (“pin-to-pin”), as known in the art. Regarding the use of smooth anvil rollers, the rollers can be steel rollers, or alternatively coated with an elastic material. By way of example only, various pattern bonding methods are shown and described in US3855046 to Hansen et al., US4333979 to Sciaraffa et al., US4374888 to Bornslaeger et al., US5110403 to Ehlert et al., US5858515 to Stokes et al., and US6165298 to Samida et al. As is known in the art, pressure, temperature, residence time, substrate composition, substrate weight, and other parameters will influence the desired degree of pressure and / or heat applied to the substrate to form bonding points. However, in many embodiments, it is desirable to apply approximately 3200 kg / cm² in the roll gap. 2(Approximately 45,000 PSI) to approximately 4600 kg / cm³ 2 A contact pressure of approximately 65,000 PSI, or in an alternative embodiment, approximately 3,400 kg / cm². 2 (Approximately 48,000 PSI) to approximately 4200 kg / cm³ 2 A contact pressure of approximately 60,000 PSI is applied. Additionally, when polypropylene filaments are included, one or more bonding rollers in the bonding rollers may have a temperature between approximately 130 °C and approximately 155 °C. Alternatively, the felt of the filaments may be bonded adhesively by spraying, gravure rolling, or other means known in the art for applying adhesives.

[0055] Figure 4 illustrates an alternative embodiment. However, in all figures, the same parts or elements will have the same reference numerals to avoid repetition. Unlike existing embodiments, the spunbond system 11 shown in Figure 4 employs a different hopper and melt extruder. In this respect, polymer particles are provided in a first hopper 12, melted, pumped through an extruder 14 into a conduit 16, and directed into a distributor block 24. The temperature of the melt extruder is set to melt the polymer at a selected temperature and pump the polymer into the spinning assembly 30. Polymer particles are also provided in a second hopper 18, melted, pumped through an extruder 20 into an associated conduit 22, and directed into the spinning assembly 30. The temperature of the second melt extruder is set to melt the polymer at a different temperature (i.e., one higher than the other) and pump the polymer into the spinning assembly 30. The high-temperature polymer stream and the low-temperature polymer stream are then converged into mutual contact via a polymer stream distributor to form a common stream of high-temperature and low-temperature polymers having two, three, or more distinct sections.

[0056] Unlike existing embodiments, the spunbond system 11 may include a multi-quench system or a dual-quench system, wherein two or more quench blowers 40, 41 guide at least two quench air streams 42, 43 from different directions into the extruded filaments 24, 25, 26. Typically, a dual-sided quench system guides quench air into the melt-extruded filaments from opposite directions. In such embodiments, the high-temperature molten polymer stream and the low-temperature molten polymer stream are also combined in such a way that the streams remain intact and distinct from each other, with a stable interface between them. However, the two polymer streams can be combined and guided into a single conduit to achieve a flow rate such as... Figure 7BThe A / B / C structure shown is positioned in a side-by-side arrangement, where both streams A and C are high-temperature molten polymer streams. For an A / B / A arrangement, the higher-temperature molten polymer will form the outer segments or strips, while the lower-temperature molten polymer will form the inner segments or strips. Various different devices and methods are known to collect molten polymer streams in such strip or segmented configurations. In one embodiment, as referenced... Figure 6 As seen, using the splitter block 31, a single flow of high-temperature molten polymer 110 is divided into two separate flows traveling via separate conduits 112, 114. The two conduits 112, 114 that guide the high-temperature molten polymer then converge on opposite sides of a junction 117. A lower third conduit 111, aligned with conduits 112, 114, guides the low-temperature molten polymer downwards and laterally, directing the low-temperature molten polymer into the central portion of the junction 117. The combined polymer flows retain their distinct segments and form a single composite flow 116 of high-temperature and low-temperature polymers in an A / B / A configuration. In addition to the splitter block, stack plate designs with integrated channels in the stack plate can also be used. Apparatus and methods for forming composite molten polymer flows are described by way of non-limiting example in US3761211 to Parkinson, US3924990 to Schrenk, and US5234649 to Cloeren et al.

[0057] After passing through distributor 32, screen 33, and support plate 34, the composite stream of molten polymer is guided onto the upper surface of the spinneret as different segments or bands covering different regions or zones. In this respect, only the high-temperature molten polymer is guided into the first zone adjacent to the first quenching airflow and discharged from the corresponding outlet port. The low-temperature polymer is the only polymer guided into the centrally positioned second zone and discharged from the corresponding outlet port. Furthermore, only the high-temperature molten polymer is guided into the third zone adjacent to the second quenching airflow and discharged from the corresponding outlet port.

[0058] In some embodiments, particularly those where quenching air is directed from two different directions, the high-temperature polymer and the low-temperature polymer are directed into at least three different zones within the spinneret. As can be most clearly seen with reference to Figures 4 and 5, the high-temperature molten polymer is directed into both a first zone A and a third zone C of the spinneret 35, adjacent to two opposing longitudinal edges 36, 38, near the first quench blower 40 and the second quench blower 41, and the first quench air flow 42 and the second quench air flow 43. The high-temperature molten polymer travels downward in the first zone A and the third zone C through corresponding inlet openings and capillaries, and is extruded through associated outlet ports located along their respective edges 36, 38 and near the quench air flows 42, 43. Thus, the first bundle or curtain 24 and the third bundle or curtain 25 of the extruded molten strands or filaments are formed near the second quench blowers 42, 41, and such that both filaments in these bundles 24, 25 are directly impacted first by the corresponding first quench air flow 42 and the second quench air flow 43. Regions A, B, and C are positioned such that region B of the low-temperature molten polymer is located at the center and / or between regions A and C. In this respect, the first curtain 24 of the filament shields the second curtain 26 of the filament from the direct impact of the first quenching airflow 42, and the third curtain 25 of the filament shields the second curtain 26 of the filament from the direct impact of the second quenching airflow 43. Therefore, the first quenching airflow 42 and the second quenching airflow 43 will first impact and pass through the outer first curtain or bundle 24 and the outer third curtain or bundle 25 of the filament, causing the quenching airflow to heat up before impacting the centrally positioned second curtain or bundle 26 of the filament. As described above, this will help improve processing and produce a more uniform frosted white line throughout the filament bundle.

[0059] refer to Figure 5A and Figure 5BThe high-temperature polymer can be introduced and exported into first zone A and third zone C, which include all capillary and / or outlet ports within a certain distance from the first extrusion edge line 92 and the second extrusion line 94, both of which are close to the quench air blowers 40, 41 and the corresponding quench air flows 42, 43. In some embodiments, the first and third zones can extend inward from the respective extrusion edges 92, 94 by a distance equal to or greater than 2 cm, 3 cm, 4 cm, 5 cm, 6 cm, 7 cm, 8 cm, 9 cm, 10 cm, 12 cm, or 14 cm. Furthermore, in various embodiments including a double-sided quenching implementation, the low-temperature polymer can be guided into a different second zone B, which is confined to the capillary and / or outlet ports between the first and second zones. In this respect, the second zone B can overlap with and extend from the central extrusion line 96 by a certain distance. In some embodiments, the second zone B may extend outward from the extrusion centerline 96 (in each longitudinal direction) by a distance equal to or greater than 2 cm, 3 cm, 4 cm, 5 cm, 6 cm, 7 cm, 8 cm, 9 cm, 10 cm, or 12 cm. The second zone may be adjacent to either or both of the first zone A and the third zone C, or there may be intermediate zones separating them. In some embodiments, multiple rows may exist between the first and second zones, and / or between the second and third zones. The rows in the intermediate sections may, for example, have capillary and outlet ports for extruding a high-temperature polymer, and capillary and / or outlet ports for extruding a low-temperature polymer. In this respect, the interface between the high-temperature and low-temperature polymers may have a curved shape, such that the low-temperature polymer flow has a lenticular shape (i.e., biconvex) or an hourglass shape (i.e., biconcave).

[0060] In other embodiments, the high-temperature polymer can be guided into a first region A, which extends the length of the extrusion region relative to the extrusion region and extends inward from the first extrusion edge line 92 by a distance between approximately 5%-40%, 10%-40%, 10%-35%, 15%-30%, or 20%-30% of the width of the extrusion region. Similarly, the high-temperature polymer can also be guided into a third region C, which extends the length of the extrusion region and extends inward from the second extrusion edge line 94 by a distance between approximately 5%-40%, 10%-40%, 10%-35%, 15%-30%, or 20%-30% of the width of the extrusion region. Furthermore, only the cryogenic polymer can be guided into the second zone B, which is located between the first zone A and the third zone C, and overlaps with the center line 96 of the extrusion zone, and extends outward from the center line 96 across a distance of approximately 20%-90%, 20%-80%, 30%-80%, 30%-70%, and 40%-60% of the width of the extrusion zone.

[0061] In some embodiments, particularly those involving bilateral quenching, the high-temperature polymer can be guided into the two quenching edge sides of the spinneret in a manner that spans the entire length of the extrusion region and extends inward from the quenching edge sides 36, 38 to respectively cover at least about 10%, 12%, 15%, 20%, 25%, 30%, 35%, or 40% of the corresponding capillary and / or outlet port. Furthermore, the low-temperature polymer can be guided into the central region of the spinneret (away from the quenching side) in a manner that spans the entire length of the extrusion region and extends along the width of the extrusion region to respectively cover at least about 20%, 30%, 40%, 50%, 60%, 70%, 76%, or 80% of the corresponding capillary and / or outlet port. As a specific example, the high-temperature polymer can be directed to approximately 10%-40% or 15%-35% of the capillary and / or outlet port adjacent to the first quenching side, and can also be directed to approximately 10%-40% or 15%-35% of the capillary and / or outlet port adjacent to the second quenching side, and the low-temperature polymer can be directed to 20%-80% or 30%-70% of the capillary and / or outlet port located at the center.

[0062] In some embodiments, the first, second, and / or third zones extend along the entire MD length of the conduit row to provide a bundle or curtain of sufficient quality and thickness, thereby providing one or more of the benefits described herein. However, it should be understood that the interface between zones can be defined by a substantially linear or curved shape. For example, the actual interface between the high-temperature polymer flow and the low-temperature polymer flow within the spinneret can have a substantially rectangular shape, thereby providing a bundle or curtain of substantially uniform thickness. In other embodiments, the high-temperature polymer and low-temperature polymer interface within the spinneret can be curved, such as a generally concave or convex shape between them. For example, the outlet port for extruding the high-temperature polymer can present a filament bundle with a concave shape along the inner segment, and the outlet port for extruding the low-temperature polymer can present a biconvex shape. Additionally, it should be understood that the inlet opening located at or near the polymer-polymer interface can absorb and include portions of both the high-temperature polymer and the low-temperature polymer. However, incorporating both polymers into a single conduit and outlet port will generally be limited, and such a filament will consist of only a small number of formed filaments.

[0063] One advantage of the method of the present invention is that by allowing the polymer to travel as independent streams adjacent to each other through the various sections of the upstream process of the spinneret, heat transfer occurs to a certain extent at the interface, thereby creating a temperature gradient. The quenching air will also be gradually cooled as it passes through the filament. Therefore, both the quenching air temperature and the filament temperature will gradually decrease with distance from the quenching air system and / or from the first extrusion line. Thus, this can provide further improved spinning conditions, formation of more uniform filament size, and / or reduction in filament breakage.

[0064] In yet another embodiment, again concerning a unilateral quenching system, the polymer stream may further comprise a high-temperature polymer stream, a low-temperature polymer stream, and an intermediate-temperature polymer stream, wherein the temperature of the intermediate polymer stream is between the temperatures of the high-temperature and low-temperature polymer streams. In such embodiments, the aggregate stream may have characteristics such as Figure 7B The A / B / C parallel structure shown has the high-temperature polymer stream and the lowest-temperature polymer stream forming the outer side, while the medium-temperature polymer stream forms the center or middle section. The three streams and zones can utilize the dimensions and positions of the three zones mentioned above, despite having a single quenching system, such that the high-temperature molten polymer is guided to the first zone adjacent to the quenching side, the medium-temperature molten polymer is guided to the second (center) zone, and the low-temperature molten polymer is guided to the third zone adjacent to the opposite side. In this respect, the single quenching airflow will first impact the filament bundle extruded from the high-temperature molten polymer, then impact the filament bundle formed from the medium-temperature molten polymer, and finally impact the filament bundle formed from the low-temperature molten polymer.

[0065] Similarly, it should be understood that for a double-quench system, the molten polymer stream can provide additional molten polymer sections at different temperatures. For example, five streams with a generally strip-shaped A / B / C / B / A structure (such as reference) can be provided. Figure 7C As seen, the outermost stream or section A contains the polymer with the highest temperature, the innermost section or stream C contains the polymer with the lowest temperature, and the middle stream or section B contains the polymer with an intermediate temperature, i.e., a temperature lower than the high-temperature molten polymer stream A but higher than the low-temperature molten polymer stream C. Extruding the corresponding filament bundles will result in a sequential quenching of the bundles, first impacting the outer, warmer filament bundles, then the medium-temperature filament bundles, and finally the low-temperature filament bundles located in the center.

[0066] The resulting nonwoven web ideally possesses high tensile strength, uniform opacity (coverage), and / or a pleasing hand feel. For many applications, bonded nonwoven webs can achieve less than approximately 175 g / m². 2 The basis weight. In some embodiments, the nonwoven web may have a basis weight of less than about 150 g / m. 2 120 g / m 2 90 g / m 2 60 g / m 2 45 g / m 2 35 g / m 2 30g / m 2 25 g / m 2 20 g / m 2 Or even 18 g / m 2 The basis weight, and further, in some embodiments, may have a basis weight exceeding approximately 8 g / m³. 2 10 g / m 2 Or 12 g / m 2 The basis weight. Additionally, spunbond filament nonwoven webs can be used alone or in combination with multilayer composites. For example, spunbond filament nonwoven webs (S) can be combined with a film (F) to form S / F, S / F / S, S / S / F / S, or other multilayer composites. As another example, spunbond filament nonwoven webs (S) can be combined with other nonwoven webs such as meltblown fiber webs (M) to form S / M, S / M / S, S / M / M / S, S / S / M / S, or other multilayer composites.

[0067] Various thermoplastic polymer compositions are believed to be suitable for use in conjunction with the present invention. By way of non-limiting examples, suitable thermoplastic polymers include polyolefins (e.g., polyethylene, polypropylene, polybutene, etc.), polyesters (e.g., polylactic acid, polyethylene terephthalate, etc.), polyamides (e.g., nylon), polystyrene, etc. Furthermore, blends and combinations of the above substances are suitable for use in conjunction with the present invention. The thermoplastic polymer composition may comprise a polyolefin composition containing more than 50% by weight of polyolefin, such as about 51% to 99%, 60% to 98% by weight, or even 80% to 98% by weight, based on the weight of the thermoplastic composition. Suitable polyolefins include homopolymers, copolymers, and terpolymers of, for example, ethylene (e.g., low-density polyethylene, high-density polyethylene, linear low-density polyethylene, etc.), propylene (e.g., syndiotactic, atactic, isotactic, etc.), butene, etc. The polymer composition may comprise homopolymers or homogeneous or non-homogeneous blends of two or more thermoplastic polymers. Furthermore, as is known in the art, one or more additives may be added to the thermoplastic polymer composition, including, for example, one or more fillers, colorants (e.g., TiO2), antioxidants, softeners, surfactants, slip agents, etc. In particular, as is well known in the art, one or more slip agents (such as fatty acid amides) may be added to the polymer composition for melt spinning.

[0068] In some embodiments, the thermoplastic polymer composition forming the high-temperature stream will be the same as the thermoplastic polymer composition forming the low-temperature stream. However, in other embodiments, the polymer streams may differ in one or more limited aspects, such as including different levels of minor components or additives. For example, the high-temperature stream and the low-temperature stream may each contain about 60% to 98% of the same polymer, and differ only in the type and / or amount of the minor components. As an example, the high-temperature polymer stream may contain 60%-99%, 70%-98%, 80%-98%, or 90%-98% of a first propylene polymer and about 1%-40%, 2%-30%, 2%-20%, or 2%-10% of a second thermoplastic polymer different from the first propylene polymer. Furthermore, the cryogenic polymer stream of the second polymer may comprise 60%-98%, 70%-98%, 80%-98%, or 90%-98% of the first propylene polymer and approximately 2%-40%, 2%-30%, 2%-20%, or 2%-10% of a third thermoplastic polymer different from both the first propylene polymer and the second polymer. In yet another embodiment, both the high-temperature polymer stream and the cryogenic polymer stream may comprise the same second polymer and differ only in quantity, such as wherein the difference in the amount of the second polymer in the stream is less than 20%, 15%, 12%, 10%, or 5%. Further still, only one of the two streams may contain the second polymer. More specifically, the polymer component of the high-temperature stream may comprise 100% of the first polymer, and the cryogenic stream may comprise 70%-99%, 80%-98%, or even 90%-98% of the same first polymer and approximately 1%-30%, 2%-20%, or even 2%-10% of a second thermoplastic polymer different from the first polymer. In some embodiments, the polymer compositions forming the high-temperature stream and the low-temperature stream and the corresponding filament may each contain more than 60%, 65%, 70%, 75%, 80%, 85%, or 90% of the same olefin polymer, ethylene polymer, or propylene polymer, and have melting points that differ from each other by + / -15°C, + / -10°C, or + / -5°C. As an example, the high-temperature stream and the corresponding filament may contain a first propylene polymer composition, and the low-temperature stream and the corresponding filament may contain a second propylene polymer composition, wherein the melting point of the first propylene polymer composition is not higher than the melting point of the second propylene polymer composition by no more than 15°C, 12°C, 10°C, 8°C, or 5°C.

[0069] It should be understood that although the invention has been described in detail with respect to specific embodiments and / or examples thereof, it will be apparent to those skilled in the art that various changes, modifications, and other alterations can be made to the invention without departing from its spirit and scope. Therefore, it is intended that the claims cover or encompass all such modifications, alterations, and / or changes.

[0070] Implementation method:

[0071] Implementation Method 1. A method for manufacturing nonwoven webs, comprising:

[0072] A spinneret is provided having an upper surface, a lower surface, and opposing first and second sides, and further wherein the spinneret includes a pattern of a conduit extending through the thickness of the spinneret, the pattern of the conduit forming an extrusion region between the first and second sides, and further wherein the conduit has an inlet opening on the upper surface and an outlet opening on the lower surface.

[0073] The first flow of molten propylene polymer at a first temperature is directed only into the region adjacent to the first side of the spinneret;

[0074] The second flow of molten propylene polymer at a second temperature is directed only to a region away from the first side of the spinneret, wherein the second temperature is lower than the first temperature;

[0075] The first flow of molten propylene polymer is extruded through the outlet opening in the first region of the spinneret, thereby forming a first curtain of molten monocomponent filaments. The first region extends the length of the extrusion area and extends inward from the extrusion area adjacent to the first side, having a width of at least 3 cm, 4 cm, 5 cm, 6 cm, 7 cm, 8 cm, 9 cm, 10 cm, 12 cm or 14 cm.

[0076] The second flow of molten propylene polymer is extruded only through the outlet opening of the second zone, thereby forming a second curtain of molten monocomponent filament; the second zone is distal to the first side, wherein the first zone is between the second zone and the first side, and further, wherein the second zone extends the entire length of the extrusion region and has a width of at least 3 cm, 4 cm, 5 cm, 6 cm, 7 cm, 8 cm, 9 cm, 10 cm, 12 cm or 14 cm;

[0077] A first quenching airflow is directly directed onto the first curtain of the monocomponent filament to form a first curtain of at least partially cured quenched monocomponent filament, and further, wherein the first quenching airflow continues through the first curtain of the quenched monocomponent filament to the second curtain of the monocomponent filament to form a second curtain of at least partially cured quenched monocomponent filament.

[0078] The quenched monocomponent filaments are pneumatically drawn to reduce their diameter;

[0079] The stretched single-component filaments are deposited on a forming surface to form a nonwoven web.

[0080] 2. The method as described in embodiment 1, wherein the first region extends between 20%-80%, 25%-75%, 35%-65%, or 40%-55% of the width of the extrusion region, and further wherein the second region extends between 20%-80%, 25%-75%, 35%-65%, or 40%-55% of the width of the extrusion region.

[0081] 3. The method of embodiment 1, wherein the second region extends the length of the extrusion region and extends inward from the extrusion region adjacent to the second side, having a width of at least 3 cm, 4 cm, 5 cm, 6 cm, 7 cm, 8 cm, 9 cm, 10 cm, 12 cm or 14 cm.

[0082] 4. The method of any one of embodiments 1 to 3, wherein the difference between the first temperature and the second temperature is an amount between about 3°C ​​and 50°C, 5°C and 45°C, 5°C and 35°C, 5°C and 30°C, or 5°C and 25°C.

[0083] 5. The method of any one of embodiments 1 to 4, wherein the first region and the second region each cover about 10%-70%, 15%-60% or 30%-60% of the outlet opening.

[0084] 6. The method of any one of embodiments 1 to 5, wherein at the interface between the first curtain and the second curtain of the molten filament, the inner edge of the first curtain of the molten monocomponent filament has a concave shape, and the second curtain of the molten monocomponent filament has a convex shape.

[0085] 7. The method according to any one of embodiments 1 to 2, 4 to 6, further includes the following step:

[0086] The third stream of molten propylene polymer is directed only into the region adjacent to the second side of the spinneret, the third stream of molten propylene polymer having the first temperature;

[0087] The third flow of molten propylene polymer is extruded through the outlet opening in the third zone of the spinneret, thereby forming a third curtain of molten monocomponent filament, wherein the second zone is between the first zone and the third zone, and further wherein the third zone extends the length of the extrusion zone adjacent to the second side and extends inward from the extrusion zone adjacent to the second side, having a width of at least 3 cm, 4 cm, 5 cm, 6 cm, 7 cm, 8 cm, 9 cm, 10 cm, 12 cm or 14 cm;

[0088] The second quenching airflow is directly directed onto the third curtain of the monocomponent filament, thereby forming at least partially cured quenched monocomponent filament third curtain, and further, wherein the second quenching airflow continues through the quenched monocomponent filament second curtain to the monocomponent filament second curtain.

[0089] 8. The method as described in embodiment 7, wherein the first region and the third region each cover about 10%-40% or 15%-35% of the outlet opening in the spinneret, and the second region covers about 20%-80% or 30%-70% of the outlet opening in the spinneret.

[0090] 9. The method of any one of embodiments 1 to 8, wherein the spinneret has an outlet opening density of about 5 to 20 outlet ports per square centimeter.

[0091] 10. The method of any one of embodiments 1 to 9, wherein the first quenching airflow has a velocity between 30 m / min and 115 m / min and a temperature below about 50°C.

[0092] 11. A method for manufacturing a nonwoven web, comprising:

[0093] A first flow of molten polymer with a first temperature is provided;

[0094] A second flow of molten polymer having a second temperature, wherein the second temperature is at least 5°C lower than the first temperature;

[0095] The first and second material flows are guided into a common conduit, wherein the first and second material flows are adjacent to each other and form at least a first interface with each other;

[0096] The adjacent first and second polymer streams are directed into the distributor, and each of the adjacent first and second polymer streams is diffused over the extended area, wherein the existing interface between the first and second streams is maintained.

[0097] A spinneret is provided in fluid communication with the dispenser. The spinneret has an upper surface, a lower surface, a first longitudinal side, and a second longitudinal side. Further, the spinneret includes a pattern of conduits extending from the upper surface to the lower surface. Further, the conduits form an extrusion region formed by a first extrusion line adjacent to the first longitudinal side and a second extrusion line adjacent to the second longitudinal side.

[0098] The first polymer stream is directed into the conduit located in a first region of the spinneret, the first region being adjacent to the first longitudinal side and extending entirely along the length of the extrusion region, and extending inward from the first extrusion line to cover approximately 5%-40%, 20%-80%, 25%-75%, 30%-70%, or 40%-60% of the conduit in the spinneret, and the first polymer stream is extruded through the conduit in the first region and exits from the conduit in the first region, thereby forming a first curtain of molten monocomponent filaments having a third temperature;

[0099] The second propylene polymer stream is guided into a conduit located in a second zone of the spinneret, the second zone being remote from the first longitudinal side, and wherein the first zone completely separates the second zone from the first longitudinal side, and further wherein the second zone extends along the length of the extrusion region and along the width of the extrusion region to cover 20%-90%, 20%-80%, 25%-75%, 30%-70%, or 40%-60% of the conduit in the spinneret, and the second polymer stream is extruded through the conduit in the second zone and exits from the conduit in the second zone, thereby forming a second curtain of melted monocomponent filaments having a fourth temperature, and wherein the fourth temperature is lower than the third temperature;

[0100] The first quenching airflow is directly directed onto the first curtain of the monocomponent filament and at least partially cures the first curtain of the monocomponent filament, and further, wherein the first quenching airflow continues through the first curtain of the filament to the second curtain of the filament, at least partially curing the second curtain of the filament.

[0101] The monocomponent filaments are pneumatically drawn to reduce their diameter;

[0102] The drawn filaments are deposited on the forming surface to form a nonwoven web.

[0103] 12. The method of embodiment 11, wherein the difference between the first temperature and the second temperature is greater than about 5°C, 8°C, 10°C, 12°C, 15°C or 18°C ​​and less than about 50°C, 45°C, 42°C, 40°C, 38°C, 35°C, 30°C or even 28°C.

[0104] 13. The method of any one of embodiments 11 to 12, wherein the first region extends inward to span between 20%-80%, 25%-75%, 35%-65%, or 40%-55% of the width of the extruded region.

[0105] 14. The method of any one of embodiments 11 to 13, wherein the second region spans between 20%-80%, 25%-75%, 35%-65%, or 40%-55% of the width of the extrusion region.

[0106] 15. The method of any one of embodiments 11 to 14, wherein the first region and the second region have substantially rectangular shapes.

[0107] 16. The method of any one of embodiments 11 to 15, further comprising the step of guiding the first and second streams through a screen after the first and second streams leave the distributor and before they enter the spinneret.

[0108] 17. The method according to any one of embodiments 11 to 16 further includes the following step:

[0109] A third flow of molten polymer with a fifth temperature higher than the second temperature is provided;

[0110] The first, second, and third material flows are guided into a common conduit, wherein the second material flow is centrally located and positioned between the first and third material flows;

[0111] The first, second, and third polymer streams are directed into the distributor, and each of the adjacent first, second, and third polymer streams is diffused over the extended region, wherein each of the existing interfaces between the first, second, and third polymer streams is maintained.

[0112] The third polymer stream is guided into a conduit located in a third zone within the spinneret, the third zone being adjacent to the second longitudinal side and extending completely along the length of the extrusion region, and extending inward to cover approximately 5%-40%, 20%-80%, 25%-75%, 30%-70%, or 40%-60% of the conduit in the spinneret, the third zone completely separating the second zone and the second longitudinal side, and the third polymer stream is extruded through the conduit in the third zone and exits from the conduit in the third zone, thereby forming a third curtain of molten monocomponent filament having the third temperature;

[0113] A second quenching blower is provided adjacent to the second longitudinal side, and a second quenching airflow is directed directly onto the third curtain of the monocomponent filaments, and at least partially solidifies the third curtain of the filaments, and further, wherein the second quenching airflow continues through the third curtain of the monocomponent filament curtain to the second curtain of the monocomponent filaments.

[0114] 18. The method of any one of embodiments 11 to 17, wherein the spinneret has about 5 to 20 spinnerets / cm 2 The density of the conduits between them.

[0115] 19. The method of any one of embodiments 11 to 18, wherein the third temperature and the fourth temperature differ from each other by an amount between 3°C-50°C, 5°C-45°C, 5°C-35°C, 5°C-30°C, or 5°C-25°C.

[0116] 20. The method of any one of embodiments 11 to 19, wherein the first quenching airflow has a velocity between 30 m / min and 115 m / min and a temperature below about 50°C.

[0117] 21. The method of any one of embodiments 11 to 20, wherein the first flow and the second flow form two segmented strip configurations within the common conduit.

[0118] 22. The method of any one of embodiments 1 to 21, wherein the first polymer stream and the second polymer stream comprise a polymer composition consisting substantially of the same composition.

[0119] 23. The method of any one of embodiments 1 to 22, wherein the first polymer stream and the second polymer stream are composed of the same polymer composition.

[0120] 24. The method of any one of embodiments 11 to 23, wherein the first polymer stream comprises a first polymer composition and the second polymer stream comprises a second polymer composition different from the first polymer composition.

[0121] 25. The method of any one of embodiments 1 to 22, wherein the first polymer composition and the second polymer composition each comprise at least 60%, 70%, 80% or 90% of the same propylene polymer.

[0122] 26. The method of any one of embodiments 1 to 22, wherein the first polymer composition and the second polymer composition have a melting point difference of less than about 15°C, 12°C, 10°C, 8°C or 5°C.

[0123] 27. The method of any one of embodiments 1 to 22, wherein the first polymer stream and the second polymer stream are substantially composed of the same polymer composition.

[0124] 28. The method of any one of embodiments 7 to 10 and 17 to 22, wherein the first flow, the second flow, and the third flow form three segmented strip configurations within the common conduit.

[0125] 29. The method of any one of embodiments 7 to 10 and 17 to 22, wherein the first polymer stream, the second polymer stream and the third polymer stream comprise a first polymer composition, a second polymer composition and a third polymer composition, and further wherein the first polymer composition and the third polymer composition comprise the same polymer composition.

[0126] 30. The method of embodiment 29, wherein the first polymer composition and the second polymer composition each comprise at least 60%, 70%, 80% or 90% of the same propylene polymer.

Claims

1. A method for manufacturing nonwoven webs, comprising: A spinneret is provided having an upper surface, a lower surface, and opposing first and second sides, and further wherein the spinneret includes a pattern of a conduit extending through the thickness of the spinneret, the pattern of the conduit forming an extrusion region between the first and second sides, and further wherein the conduit has an inlet opening on the upper surface and an outlet opening on the lower surface. The first flow of molten propylene polymer at a first temperature is directed only into the region adjacent to the first side of the spinneret; The second flow of molten propylene polymer at a second temperature is directed only to a region away from the first side of the spinneret, wherein the second temperature is lower than the first temperature; The first flow of molten propylene polymer is extruded through the outlet opening in the first region of the spinneret, thereby forming a first curtain of molten monocomponent filaments. The first region extends the length of the extrusion area and extends inward from the extrusion area adjacent to the first side, having a width of at least 3 cm, 4 cm, 5 cm, 6 cm, 7 cm, 8 cm, 9 cm, 10 cm, 12 cm or 14 cm. The second flow of molten propylene polymer is extruded only through the outlet opening of the second zone, thereby forming a second curtain of molten monocomponent filament; the second zone is distal to the first side, wherein the first zone is between the second zone and the first side, and further, wherein the second zone extends the entire length of the extrusion region and has a width of at least 3 cm, 4 cm, 5 cm, 6 cm, 7 cm, 8 cm, 9 cm, 10 cm, 12 cm or 14 cm; A first quenching airflow is directly directed onto the first curtain of the monocomponent filament to form a first curtain of at least partially cured quenched monocomponent filament, and further, wherein the first quenching airflow continues through the first curtain of the quenched monocomponent filament to the second curtain of the monocomponent filament to form a second curtain of at least partially cured quenched monocomponent filament. The quenched monocomponent filaments are pneumatically drawn to reduce their diameter; The drawn single-component filaments are deposited on the forming surface to form a nonwoven web; At the interface between the first curtain and the second curtain of the molten filament, the inner edge of the first curtain of the molten monocomponent filament has a concave shape, and the second curtain of the molten monocomponent filament has a convex shape.

2. The method of claim 1, wherein the first region extends between 20%-80%, 25%-75%, 35%-65%, or 40%-55% of the width of the extrusion region, and further wherein the second region extends between 20%-80%, 25%-75%, 35%-65%, or 40%-55% of the width of the extrusion region.

3. The method of claim 1, wherein the second region extends the length of the extrusion region and extends inwardly from the extrusion region adjacent to the second side, having a width of at least 3 cm, 4 cm, 5 cm, 6 cm, 7 cm, 8 cm, 9 cm, 10 cm, 12 cm or 14 cm.

4. The method of claim 1, wherein the difference between the first temperature and the second temperature is between 3°C and 50°C, 5°C and 45°C, 5°C and 35°C, 5°C and 30°C, or 5°C and 25°C.

5. The method of claim 1, wherein the first zone and the second zone each cover 10%-70%, 15%-60%, or 30%-60% of the outlet opening.

6. The method of claim 1, further comprising the following step: The third stream of molten propylene polymer is directed only into the region adjacent to the second side of the spinneret, the third stream of molten propylene polymer having the first temperature; The third flow of molten propylene polymer is extruded through the outlet opening in the third zone of the spinneret, thereby forming a third curtain of molten monocomponent filament, wherein the second zone is between the first zone and the third zone, and further wherein the third zone extends the length of the extrusion zone adjacent to the second side and extends inward from the extrusion zone adjacent to the second side, having a width of at least 3 cm, 4 cm, 5 cm, 6 cm, 7 cm, 8 cm, 9 cm, 10 cm, 12 cm or 14 cm; The second quenching airflow is directly directed onto the third curtain of the monocomponent filament, thereby forming at least partially cured quenched monocomponent filament third curtain, and further, wherein the second quenching airflow continues through the quenched monocomponent filament second curtain to the monocomponent filament second curtain.

7. The method of claim 6, wherein the first region and the third region each cover 10%-40% or 15%-35% of the outlet opening in the spinneret, and the second region covers 20%-80% or 30%-70% of the outlet opening in the spinneret.

8. The method of claim 1, wherein the spinneret has an outlet opening density of between 5 and 20 outlet ports per square centimeter.

9. The method of claim 1, wherein the first quenching airflow has a velocity between 30 m / min and 115 m / min and a temperature below 50°C.

10. A method for manufacturing a nonwoven web, comprising: A first flow of molten polymer with a first temperature is provided; A second flow of molten polymer having a second temperature, wherein the second temperature is at least 5°C lower than the first temperature; The first and second material flows are guided into a common conduit, wherein the first and second material flows are adjacent to each other and form at least a first interface with each other; The adjacent first and second polymer streams are directed into the distributor, and each of the adjacent first and second polymer streams is diffused over the extended area, wherein the existing interface between the first and second streams is maintained. A spinneret is provided in fluid communication with the dispenser. The spinneret has an upper surface, a lower surface, a first longitudinal side, and a second longitudinal side. Further, the spinneret includes a pattern of conduits extending from the upper surface to the lower surface. Further, the conduits form an extrusion region formed by a first extrusion line adjacent to the first longitudinal side and a second extrusion line adjacent to the second longitudinal side. The first polymer flow is directed into the conduit located in a first region of the spinneret, the first region being adjacent to the first longitudinal side and extending completely along the length of the extrusion region, and extending inward from the first extrusion line to cover 5%-40%, 20%-80%, 25%-75%, 30%-70%, or 40%-60% of the conduit in the spinneret, and the first polymer flow is extruded through the conduit in the first region and exits from the conduit in the first region, thereby forming a first curtain of molten monocomponent filaments having a third temperature; A second propylene polymer stream is directed into a conduit located in a second zone of the spinneret, the second zone being remote from the first longitudinal side, and wherein the first zone completely separates the second zone from the first longitudinal side, and further wherein the second zone extends along the length of the extrusion region and along the width of the extrusion region to cover 20%-90%, 20%-80%, 25%-75%, 30%-70%, or 40%-60% of the conduit in the spinneret, and the second polymer stream is extruded through the conduit in the second zone and exits from the conduit in the second zone, thereby forming a second curtain of molten monocomponent filament having a fourth temperature, and wherein the fourth temperature is lower than the third temperature; The first quenching airflow is directly directed onto the first curtain of the monocomponent filament and at least partially cures the first curtain of the monocomponent filament, and further, wherein the first quenching airflow continues through the first curtain of the filament to the second curtain of the filament, at least partially curing the second curtain of the filament. The monocomponent filaments are pneumatically drawn to reduce their diameter; The drawn filaments are deposited on the forming surface to form a nonwoven web; At the interface between the first curtain and the second curtain of the molten filament, the inner edge of the first curtain of the molten monocomponent filament has a concave shape, and the second curtain of the molten monocomponent filament has a convex shape.

11. The method of claim 10, wherein the difference between the first temperature and the second temperature is greater than 5°C, 8°C, 10°C, 12°C, 15°C or 18°C ​​and less than 50°C, 45°C, 42°C, 40°C, 38°C, 35°C, 30°C or even 28°C.

12. The method of claim 10, wherein the first region extends inward to span between 20%-80%, 25%-75%, 35%-65%, or 40%-55% of the width of the extruded region.

13. The method of claim 10, wherein the second region spans between 20%-80%, 25%-75%, 35%-65%, or 40%-55% of the width of the extruded region.

14. The method of claim 10, wherein the first region and the second region have a rectangular shape.

15. The method of claim 10, further comprising the step of guiding the first and second streams through a screen after they leave the distributor and before they enter the spinneret.

16. The method of claim 10, further comprising the step of: A third flow of molten polymer with a fifth temperature higher than the second temperature is provided; The first, second, and third material flows are guided into a common conduit, wherein the second material flow is centrally located and positioned between the first and third material flows; The first, second, and third polymer streams are directed into the distributor, and each of the adjacent first, second, and third polymer streams is diffused over the extended region, wherein each of the existing interfaces between the first, second, and third polymer streams is maintained. The third polymer stream is guided into a conduit located in a third zone within the spinneret, the third zone being adjacent to the second longitudinal side and extending completely along the length of the extrusion region, and extending inward to cover 5%-40%, 20%-80%, 25%-75%, 30%-70%, or 40%-60% of the conduit in the spinneret, the third zone completely separating the second zone and the second longitudinal side, and the third polymer stream is extruded through the conduit in the third zone and exits from the conduit in the third zone, thereby forming a third curtain of molten monocomponent filament having the third temperature; A second quenching blower is provided adjacent to the second longitudinal side, and a second quenching airflow is directed directly onto the third curtain of the monocomponent filaments, and at least partially solidifies the third curtain of the filaments, and further, wherein the second quenching airflow continues through the third curtain of the monocomponent filament curtain to the second curtain of the monocomponent filaments.

17. The method of claim 10, wherein the spinnerets have 5 to 20 per cm. 2 The density of the conduits between them.

18. The method of claim 10, wherein the third temperature and the fourth temperature differ from each other by an amount between 3°C-50°C, 5°C-45°C, 5°C-35°C, 5°C-30°C, or 5°C-25°C.

19. The method of claim 10, wherein the first quenching airflow has a velocity between 30 m / min and 115 m / min and a temperature below 50°C.

Images