JP2001519488A - Method and apparatus for in-line splitting of multicomponent fibers and formation of nonwovens - Google Patents

Abstract

(57) [Summary] By splitting and separating fibers in-line (in the process) in the spunbond method by the difference in thermal shrinkage of two or more components of multicomponent fibers such as ribbon-shaped bicomponent fibers And a method for producing a nonwoven fabric having excellent properties. Two polymers that shrink to a substantially different extent upon the application of heat are used as components of the multicomponent fiber and are discharged through spinning holes (32) arranged in a spinneret (30). Ribbon-shaped fibers having alternating first and second components that differ by at least about 10% in heat shrinkage result in rapid and highly splitting and separation of the fiber components. The array of multicomponent fibers is thinned prior to being drawn through the aspirator (36) and collected on the web forming belt (42), and then at a temperature sufficient to develop the differential thermal shrinkage of the polymer components. The web is transferred to a heating unit (50) which heats the web, whereby the segments of fibers comprising the above-mentioned polymer components are split in approximately one second. After splitting and separating the fibers, the webs are joined to form a nonwoven.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing a nonwoven fabric, and in particular, each component constituting a multicomponent synthetic fiber obtained by melt spinning exhibits different heat shrinkage, whereby the multicomponent fiber Microfibers divided and separated in parallel with the discharge
rs) for producing a fabric consisting of: Description of technology related to the background art Large bulkiness and flexibility, absorbent products with excellent stiffness and drapes, barrier properties (blocking properties) and filtration characteristics used in medical clothing and filtration material products, etc. Various attempts have been made to produce nonwoven fabrics having improved properties. It is also known that nonwovens with desirable performance can be made from splittable multicomponent fibers. Such multicomponent fibers are typically microfilaments or segments of a cross-section of a fiber, the segments being composed of at least two different polymers arranged continuously extending in the longitudinal direction of the fiber. . By dividing such a multi-component fiber into each constituent segment after ejection, it is possible to produce an ultrafine fiber having desirable characteristics.

[0002] A number of techniques have been used to separate the individual segments that make up multicomponent fibers. In particular, the fiber segments can be separated by applying a mechanical force to the fiber, such as a high pressure water jet, beating, carding, calendering, or other mechanical treatment of the fiber. As an alternative to these, one component constituting the multi-component fiber can be dissolved by applying a solvent to the fiber so as to leave a segment formed of undissolved components.

[0003] Gilles intends to include the content here by quoting all of it.
pie et al. U.S. Pat. No. 5,783,503 discloses that while fibers are free falling from a spout where they are ejected, a plurality of fibers are deposited on a collection surface such as a web former or belt. Disclosed is to perform splitting of component fibers. U.S. Pat. No. 5,783,503 discloses drafting, drawing or shrinking fibers in a stream of pressurized air or steam, generating a triboelectric on at least one of the components, A number of possible techniques for splitting the fibers are disclosed, including applying an external electric field to the fibers and exposing the falling fibers to turbulent air. These techniques rely on a number of properties of different polymer components, such as intermixability, melting point, crystallinity, viscosity, differences in electrical conductivity, and the ability to generate triboelectric charges.

The method disclosed in US Pat. No. 5,783,503 is disclosed in US Pat. No. 5,783,503, in which fibers are free-falling from a spout where the fibers are being dispensed and the fibers, such as a web forming platform or belt. Since the separation and separation of multicomponent fibers is essentially required to be completed before it is deposited on the collection surface, additional methods must be used to make fiber separation effective. It requires the placement of the device or device in a particular configuration along the vertical direction of the fiber. For example, means for generating agglomeration under low pressure, means for applying steam, means for supplying highly turbulent air and / or means for applying an external electric field are required to achieve a proper division of the fibers. A device for obtaining such an effect is:
Significantly increases the complexity and cost of this known method and limits the method for certain operating conditions. Furthermore, it is necessary to mix additives in the polymer in order to modify the properties of the polymer so as to achieve sufficient resolution and separation.

[0005] US Pat. No. 5,5,100, incorporated herein by reference in its entirety.
No. 7,759,926 discloses another technique for dividing and separating segments of a multicomponent fiber, in which hot water is applied to a web for the purpose of promoting the division. In particular, a method in which the web of fibers is passed through a hot water bath or a spray of steam or a mixture of air and hot water while being transferred. Of course, at least one of the polymer components of the multicomponent fiber must be modified to be hydrophilic or hydrophobic, and the polymer must have at least 0.5 (cal / cm ³ ) ^1/2 There must be a difference in solubility index. When water or steam is applied to the web, the segments formed of the hydrophilic polymer absorb water and split and separate from the weak or non-hydrophobic polymer segments. In other words, the function used here for realizing the splitting of the fibers lies in the absorption of water by the hydrophilic polymer.

The method disclosed in US Pat. No. 5,759,926 has a number of significant limitations. This means that the fibers need to be exposed to a hot aqueous solution for a considerable period of time because the division and separation of the fiber segments is caused by the absorption of water. In particular, separation,
It takes as long as 30 seconds to complete the splitting process, which severely limits the speed at which the web is transported and formed. In addition, this method requires the application of an aqueous solution to the web, requiring a drum dryer to dry the web prior to bonding, adding time consuming steps, resulting in cost and method complexity. Significantly increased.

[0007] Therefore, it is necessary to realize a simple, inexpensive, and rapid spunbonding method capable of dividing fibers in-line (in a process) to form a nonwoven fabric made of fine denier and having preferable properties as a fabric. It is. SUMMARY OF THE INVENTION The object of the present invention is to provide good coverage (non-porous or non-porous), bulk, flexibility,
It is in the production of non-woven fabrics with excellent properties such as firm softness, drape and good barrier properties.

A further object of the present invention is to realize a high degree of division and separation between segments of multi-component fibers in-line (in a process) in a spunbond method for producing a nonwoven fabric composed of fine denier fibers. It is in. Another object of the present invention is to provide a relatively simple, reliable, and inexpensive method within a spunbond process to quickly split in-line into component fiber segments of multicomponent fibers, Is to separate.

Yet another object of the present invention is to provide for the use of differential thermal shrinkage of polymer components to cause separation of fiber segments of multicomponent fibers. The above objects of the present invention are achieved separately and in combination, and unless the invention is explicitly stated otherwise in the following claims, said object is achieved by
It is not intended to be understood as requiring that they be combined or more.

According to the present invention, splitting and separating fibers in-line in a spunbond process is achieved by a difference in heat shrinkage of two or more components of a multicomponent fiber such as, for example, a ribbon-shaped bicomponent fiber. . Two or more polymers, which shrink to a substantially different extent under the action of the application of heat, are discharged from an interleaved or interleaved spinning hole array of multicomponent fibers. The array of multi-component fibers is drawn through an aspirator and reduced to a point where it is deposited on a web forming belt. Once collected on a belt, the web of fibers was transferred to a heater that heated to a temperature sufficient to produce a difference in thermal shrinkage of the polymer components, thereby forming the respective components. Separated into fiber segments. After separation of the fibers, the web is bonded,
A non-woven fabric is formed. For rapid fiber splitting, the polymer component of the multicomponent fibers of the present invention preferably has a difference in thermal shrinkage of at least approximately 10%. A ribbon-shaped multicomponent fiber having alternating first and second components each formed of two polymers provides excellent component separation and results in a nonwoven fabric having unparalleled excellent properties. It has been found by the present inventors.

[0011] Heating to cause a difference in heat shrinkage is performed by blowing hot air, blowing steam, using radiant heat or another heating method, or a combination of these methods. The heating unit is disposed along the web transport path and heats the fibers at a temperature sufficient to cause thermal shrinkage and fiber splitting, preferably within one second. Rapid splitting using differential shrinkage of the fiber components allows for the production of spunbond fabrics by the spunbond process, where separation of the components occurs in-line with spunbond fiber ejection. In particular, when the division of the fiber component is realized in a few seconds or less than one second, the web can be joined in the line immediately without interruption following the ejection of the fiber, the formation of the web and the division of the fiber component. The in-line spunbond method of the present invention produces a fine denier nonwoven fabric having properties that are desirable and improved in properties such as bulkiness, flexibility, stiff softness, drape, and barrier and filterability. The foregoing and further objects, features and advantages of the invention will be apparent from a consideration of certain embodiments, which are set forth in detail below, particularly with reference to the accompanying drawings. In the drawings, like reference numerals in the drawings refer to like elements.

BRIEF DESCRIPTION OF THE DRAWINGS FIG . 1 is a schematic view of an apparatus for carrying out a spunbonding method employing a fiber discharging and in-line fiber dividing step for forming a nonwoven fabric. FIG. 2 is a circular cross-section view of a bicomponent fiber having wedge-shaped segments. FIG.
FIG. 3 is a view of a cross section of a hollow bicomponent fiber having a circular cross section. FIG. 4 is a view of a cross section of a five-segment component composite component fiber having a cross-shaped cross section. FIG.
FIG. 3 is a view of a cross section of a 9-segment component composite component fiber having a cross-shaped cross section. FIG. 6 is a view of a cross section of a 10-segment component composite component fiber having a ribbon shape.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In accordance with an illustrative embodiment of the present invention, the in-line fiber splitting process in the spunbond process is a multi-component fiber having a ribbon shape or other suitable cross-sectional shape. Is achieved by the difference in heat shrinkage of two or more components. Here, the spun bond method refers to a method of forming a nonwoven fabric or a fiber web from small diameter fibers or filaments produced by discharging a molten polymer from a spinneret. The filaments are withdrawn while cooling and are randomly deposited on the forming surface such that the filaments form a nonwoven web. The web is then bonded using one of several known techniques for forming nonwovens. As used herein, in-line refers to a non-in-line process where the fiber ejection, splitting, and web forming are one continuous process (ie, if the ejected fibers are cut into separate rolls after being wound into rolls or separated into webs). Method).

FIG. 1 shows an apparatus 1 for producing a nonwoven fabric according to the spunbond method of the present invention.
0 is schematically described. Apparatus 10 comprises two different polymers, hereinafter polymer A,
It includes hoppers 12 and 14 in which pellets of polymer B are charged, respectively. Polymers A and B are supplied from hoppers 11 and 12, respectively, to screw-extruders 16 and 18 for melting the polymers. The molten polymer flows through heated pipes 20 and 21 to metering pumps 24 and 25, respectively, which then direct the two polymer streams to form bicomponent fibers having a selected cross-section and number of segments. To a suitable spin pack 28 having internal means for As used herein, segments and microfibers refer to those portions of the fiber that have components that are distinct from other portions of the fiber, and bicomponent is two or more segments, at least one of the segments. One refers to one material or component, and the remaining segments refer to other, different materials or components.

The term “multicomponent” as used herein refers to a fiber composed of two or more segments, in which each segment forming the fiber is composed of at least two different materials or components (therefore, the bicomponent fiber is composed of plural fibers). A fiber of the component fiber type). The spin pack 28 is used for forming the spinning holes 3 forming the bicomponent fibers discharged therethrough.
For example, the spinnerets 32 have a substantially horizontal, rectangular array, and the holes are arrayed in a manner that discharges multicomponent fibers.

Cross sections of various bicomponent fibers suitable for use in the present invention are shown in FIGS. 2-6. A bicomponent fiber having a circular cross section and a substantially circular cross section in the form of a wedge-shaped segment or pie piece is shown in FIG. The wedge-shaped segment is formed of two different polymers A and B such that adjacent segments are formed of different polymers. The fiber having the cross-section shown in FIG. 2 and its method of manufacture are described in U.S. Pat. No. 3,1, 1 the entire contents of which are incorporated herein by reference.
No. 17,362.

The arrangement shown in FIG. 2 of a multi-component fiber is generally suitable for the present invention, but is useful in splitting fiber segments, especially when the segments do not meet at the center of the fiber at its sharp tip. In some cases, you may encounter difficulties. FIG. 3 shows that the fibers are hollow and that the wedge-shaped segments do not extend to the center.
Describes multicomponent fibers having a cross-section similar to that shown in FIG. The segments of the hollow fibers shown in FIG. 3 are more easily compared to the fibers shown in FIG. 2 because the segments obtained from similar polymers are not interconnected near the center of the fibers. Split and separate reliably. The fibers shown in FIG. 3 use a spinneret to produce hollow fibers, but can be prepared using the same ejection method as the fibers shown in FIG.
A method of making this type of fiber is disclosed in U.S. Pat. No. 4,051,287, the contents of which are incorporated herein by reference in their entirety.

FIG. 4 is a cross-shaped multi-component fiber having five segments, wherein four segments of polymer A are radially located at four locations and spaced 90 ° apart. And extends outward from the central polymer B. FIG. 5 shows another 90 ° cross-shaped multi-component fiber cross-section with four 90 ° intervals to form a central polymer B segment, each having a total of nine separate segments. To describe a fiber consisting of a segment of polymer A extending radially outward from the central segment and four additional polymer B segments extending radially outward from the tips of the four polymers A. I have.

FIG. 6 shows a 10-segment bicomponent fiber having a ribbon-like cross section in which segments of polymer A and polymer B are alternately arranged side-by-side. Each segment is a fiber formed by joining adjacent segments along a line extending substantially perpendicular to the longitudinal end of the ribbon so as to have a generally rectangular cross-sectional shape. In the case where the segmentation of the fiber segments is achieved using the difference in heat shrinkage of the two polymer components, the multicomponent fibers having a ribbon-shaped cross-section are more relative to the multicomponent fibers having other cross-sections. Experiments such as the present invention have shown that a quicker and more complete separation can be obtained. Furthermore, even when incomplete splitting of the fibers occurs, the ribbon-shaped fibers have a very low bending modulus in the ribbon shape (in other words, the undivided portions of the ribbon-shaped fibers may still be twisted or tertiary). It can bend in its original direction, with a considerable degree of freedom in which adjacent fiber segments bend in different directions from each other) and are relatively much softer than fibers of other cross-sections. Thus, in the present invention, the use of multicomponent fibers having a ribbon-shaped cross-section with alternating component segments is preferred over the use of multicomponent fibers having other cross-sections as described above. The reasons are: 1) ribbon-shaped fibers are easily split, and generally all are split; 2) even if the fiber segments are not separated, the non-split ribbon shape is This is because it is much softer than split fibers.

Returning to FIG. 1, the arrangement group of the bicomponent or multicomponent fibers 34 is a spin pack 2
8 and is drawn down by aspirator 36 to which compressed air or steam is supplied from a pipe 38 to be thinned. For example, the gun-type, slot-type aspirator 36 can extend the full width in the direction corresponding to the arrangement width of the fibers, that is, the width of the web formed of the fibers.

The aspirator 36 conveys the thinned fibers 40 to a web forming screen belt 42 which is supported and driven by rolls 44 and 46. A suction box 48 is coupled to a fan (not shown) for drawing room air (outside air temperature) through the screen belt 42. As the web is formed on the screen 42, the web is heated, causing a difference in the thermal shrinkage of the fiber bicomponent material. In particular, when heated to a temperature equal to or lower than the melting point of the fiber, the polymer (eg, polymer B) is compared to the size before heating, and the other polymer (eg,
The polymer A) shrinks more than its unheated size does. The difference in heat shrinkage between the two polymers is calculated from the shrinkage ratio (%) of polymer B to the shrinkage ratio (%
) Can be measured by subtraction. When the difference in heat shrinkage is significant, crimping and fiber segment separation occur. Since an elegant and bulky nonwoven fabric having good flexibility, stiffness, drape and barrier properties can be obtained, it is desirable that high crimping and splitting of multicomponent fibers occur.

The bicomponent of the multicomponent fibers having a heat shrink difference of at least about 10%, under the heating conditions of the invention, causing a rapid and high degree of splitting of the fibers into individual segments;
And our experiments have shown that a larger difference in heat shrinkage results in a more complete and faster split. Conversely, having a difference in heat shrinkage of generally less than 10% and lacking other means of inducing splitting results in insufficient and less splitting of the fiber segments,
Our experiments have also shown that other additional means need to be applied to fully separate and split the segments of the multicomponent fiber. Thus, according to the present invention, the polymer of the multicomponent fibers to be discharged, under the heating conditions applied in the method of the present invention, preferably has a heat shrinkage difference of at least approximately 10% (for example, exiting the aspirator). Consider the fiber speed, fiber and microfiber denier and web weight per unit area, belt speed, applied heating temperature and duration and type of heating). Most preferably, the polymer of the ejected multicomponent fibers has a thermal shrinkage difference of at least about 20%, more preferably at least 25%.

According to the inventors, a particularly advantageous combination of polymers is polypropylene (Polymer A), 20 mol% of purified isophthalic acid and a powdery ester transfer inhibitor (GE).
Polyethylene terephthalate (PET) modified with Ultranox 626)
It has been found that this composition has a heat shrinkage difference of approximately 30% under the heating conditions of the present invention.

Returning to FIG. 1 again, in order to cause different heat shrinkage of the multi-component fiber, a difference in heat shrinkage between the polymer A and the polymer B occurs in the web formed on the web forming belt 42. Close to the heating unit 50 to raise the fiber temperature of the web to
(Directly above or directly below) to cause the multicomponent fibers to separate into their constituent segments. That is, the temperature of the web is lower than the melting points of polymer A and polymer B and is sufficient to cause at least one of the two polymers to shrink sufficiently to cause separation between adjacent segments of the fiber. Raise the temperature as high as possible. As used herein, the term separation and splitting means that a segment is separated from adjacent segments along at least a substantial length of the segment's longitudinal extension, but does not require complete separation (complete separation). Alternatively, nearly complete separation is desirable, although it may be achieved with certain polymer and method combinations).

Although the present invention does not require the development of crimps in the substantial sense of the fiber, certain types of crimping of the fiber may be accompanied by some type of crimping of the fiber When this occurs, the flexibility and bulkiness of the fabric are enhanced. For example, some crimping of the fiber segments usually occurs early in the onset of shrinkage, unseparated segments of the fiber exhibit crimping due to differences in shrinkage between the unseparated segments, and also fibers. The segmentation of the isolated portion of the compound has some degree of crimp development, depending on the particular polymer components and process conditions.

The heating unit 50 can be supplied with heat in a heating type, such as appropriate to cause differential shrinkage and separation of the fiber components. Non-limiting examples include blowing hot air through a web (general heating), blowing steam through a web, radiant heat radiation, and combinations thereof. As used herein, heaters and heating units refer to a single heater element or a number of heaters arranged in series along a device or web transport belt. When the application of heat is by steam, the separation of the components occurs by heating the fiber, not as a result of the adsorption of moisture, or also because the heat is carried in the form of moisture. is not. That is, the polymer component of the multicomponent fiber of the present invention does not need to be hydrophilic. In fact, the polymeric component of the multicomponent fibers of the present invention is hydrophobic.

The use of heat to split the fiber segments by differential heat shrinkage according to the present invention is less than prior art methods that rely on water absorption by hydrophilic polymers to split multicomponent fibers. Very quick separation is possible. For example, the use of heat to separate polypropylene and modified PET polymers described above means that when heat is applied to a portion of the web that travels in less than about one second, segments formed from these polymers are almost completely lost. Complete separation occurs promptly. In particular, the modified PET is generally at a temperature of 200 ° F. or higher, which is a temperature that can be quickly reached even by applying radiant heat by blowing hot air or blowing a team. Shows significant heat shrinkage. In the experimental example, if the temperature of the web was quickly raised to 250 ° F. ± 15 ° F.,
A high degree of shrinkage of the modified PET occurs immediately, resulting in separation of the fiber segments (under these conditions, polypropylene does not undergo significant shrinkage). The time required to heat portions of the web for the shrinking process to be substantially completed and fiber separation to occur is a function of the thickness of the fabric or the weight per unit of fabric. Our experiments have shown that the heating time generally increases linearly with respect to unit thickness or weight. Further, within the temperature range that causes the differential thermal shrinkage, the application of higher temperatures reduces the time required to substantially complete the shrinking process. The heating time can be adjusted by the speed of the belt transferring the web and / or the length of the portion of the web that receives heat directly from the heater (the length of the heater in the direction of movement of the belt). The heating parameters can be completed with a difference in shrinkage of about 1 second or less, and the heating unit should be at a belt speed (eg, several hundred m / min) typically used to produce nonwovens in an in-line spunbond process. It is preferred that the length be reasonable below.

Referring again to FIG. 1, after applying heat to cause the differential thermal shrinkage and separation of the multicomponent fibers, the web passes through an optional selected compacting roll and leaves the screen. Pass through the nip formed by the heated calender rolls 54 and 56. One of the calender rolls is embossed, has protrusions, and melts the fibers only at the points where the protrusions contact the web, leaving the fibers between the bonding points bulky, resulting in a good bonded nonwoven fabric. Give waist and drape.

The joining method of the present invention is not limited to the joining method described above, and other commonly used joining techniques can be used. Without limitation, through-air bonding (particularly useful at low melting temperatures commonly found in high shrinkage components), needle punching, hydroentangling
ing, high-pressure water jet). In particular, according to the pass-air bonding method, when heat is applied to the web, the temperature of the web rises to a temperature at which the difference in heat shrinkage of the high shrink polymer component occurs. As heat continues to be applied, the high shrinkage polymer tends to stick and begin to melt, rising to a temperature that allows the segments of the high shrinkage polymer to bond to adjacent polymers.

As described in the context of the spun bond method, the heat shrinkage difference method of the present invention is:
It can also be applied to web or fabric forming processes that do not require fiber bonding. The heat shrinkage difference method can be applied to, for example, a spunlaid method. It is to be understood that the invention is not limited to the particular apparatus and methods described in connection with FIG. 1, and that additional or even modified methods are within the scope of the invention. Two or more godets can be used to pull and / or relax the fibers, eg, prior to an aspirator. The downstream godet may be operated at a higher speed than the upstream godet for stretching or tensioning the fibers, or may be operated at a lower speed than the upstream godet for relaxing the fibers.

Although the above embodiments of the present invention primarily rely on the difference in thermal shrinkage after the deposition of multicomponent fibers on the web collection surface, the present invention provides for the deposition of fibers on the web forming surface. Prior to this, a method of dividing the heat shrinkage and dividing the fibers can also be adopted. Prior to depositing the fibers on the web collection surface, the method of splitting or splitting the fibers is independent of each other in such a way that the fiber segments are spun at a low denier on the order of 0.1 denier. And collect it on the belt,
A fabric is obtained with better coverage (there is no open surface in the web) and other advantageous properties described herein. In particular, the godets described above may be heated to compensate for the difference in thermal shrinkage of the fibers that causes the fibers to split, and / or other thermally conductive heating devices such as hot plates are used for this purpose. You can also.

Hot air and / or steam (saturated or overheated) can also be applied to the fibers in an aspirator to split the heat-shrinkable fiber components by the time the fibers reach the belt. Similar results can be obtained by directly heating the aspirator to a temperature sufficient to induce differential contraction. Various splitting aids may also be employed. These include, but are not limited to, additives that add a fluorinated polymer or silicone compound to one or more polymer components to allow these components to slip and split easily. One or more blowing agents that cause the components to expand relatively to the components, including applying heat with ultrasound to stimulate the two polymers to increase their relative motion and splitting It is.

The fiber segment, which is a fine fiber divided and separated by the method of the present invention, has a desired level of softness over a nonwoven fabric obtained by a known spunbond method,
A very elegant and bulky nonwoven fabric can be manufactured. A variety of additional modified fabric properties such as good drape, high filterability, barrier properties, and low coverage are obtained with the resulting ultra-low denier filaments of the split fibers of the present invention.
The nonwoven formed by the method of the present invention is useful for any product, such as a sheet for filling, where a fluffy fabric is useful. The nonwoven fabric of the present invention can be used in a variety of other commercial products including, but not limited to, diaper linings, other disposable absorbent products, barrier medical fabrics, and filters.

The following examples performed using the apparatus of FIG. 1 are used for explanation, and the present invention is not limited by these examples. EXAMPLES Example 1 Each fiber has 10 segments in which polymer A and polymer B are alternately arranged,
A spin pack that forms a rectangular array of 198 self-crimped fibers in a ribbon shape shown in FIG. 6 was used. Polymer A and polymer B were pumped at a constant rate of 0.20 g / min / hole, all 0.40 g / min / spinneret. Each spinning hole is 0.
A ribbon-shaped fiber having a length of 8 mm and a cross section of 0.2 × 2.0 mm was manufactured.

Polymer A was 12 MFR polypropylene. Polymer B is Amoco
It was a high shrink type copolymer that was polyethylene terephthalate modified from 20 mol% of purified isophthalic acid and a powdered transesterification inhibitor (GE Ultranox 626) obtained from Chemical Company. The ejected ribbon-shaped fibers were drawn through an aspirator having a 6 inch wide slot with a 0.015 inch gap. Fibers were produced at a speed of approximately 3000 m / min through a 6 inch wide slot aspirator using room temperature air pressurized at 20 psi to feed the aspirator. No noticeable splitting of the ribbon-shaped fibers leaving the aspirator was observed.

[0036] The attenuated fibers exiting the aspirator were transferred onto a screen belt to form a 4-inch wide web. The belt speed was set at 30 m / min and a fabric with a basis weight of 1.6 oz / square yard was obtained. The fiber had a denier of 1.6, and 0.16 denier for each of the 10 segments of each ribbon-shaped fiber. A radiant heater was positioned 1 inch above the web that was deposited on the belt. The heating zone was approximately 20 inches in the direction of belt travel. Using 1200 watts of radiant heat from the heater (approximately 10 watts / square inch and heating the web to 250 ° F. ± 15 ° F. in about 1 second), the fibers exhibit differential shrinkage, thereby exhibiting crimping and each fiber Separation into segments resulted in a very flexible, bulky web.

The web was passed through a compacting roll with a compacting roll pressure of 40 pounds / inch wide. This web was placed on a heat-set calender at a calendar temperature of 220 ° F.
A fabric having good flexibility and drape and unparalleled coatability, filterability and barrier properties was obtained. Example 2 0.18 grams / minute for each spinhole (0.09 grams / minute for each polymer)
Pump speed is reduced to 15 psig so that
Example 1 was repeated with the same specifications except that the outlet speed of the fiber from the aspirator was 1900 m / min. Fiber denier is 1.1 (0.
11). A fabric having a basis weight of 0.5 oz / square yard was obtained at a belt speed of 30 m / min. This example also provided a desirable fabric with unparalleled flexibility and other properties.

Example 3 The aspirator air pressure was reduced to 25 by reducing the pump speed so that 0.7 g / min (0.35 g / min for each polymer) was equally delivered to each spinning hole.
psig and the outlet speed of the fiber from the aspirator to 5000 m / min,
Example 1 was repeated with the same specifications except that the fiber denier was 2.5 (0.25 per segment). At a belt speed of 30 m / min, a fabric having a basis weight of 0.5 oz / square yard was obtained. This example also provided a desirable fabric with unparalleled flexibility and other properties.

For the purpose of producing fine denier fibers, the above example describes a ribbon-shaped fiber having 29 or 40 segments in which polymer A and polymer B are alternately arranged.
It can be applied repeatedly. Thus, for example, at 30 m / min, a fabric of 0.5 oz / square yard with 2.4 denier fiber would have 20 segment fibers into 0.12 denier per segment fabric and 40 segment fibers into segment 0.06 denier per fabric.

For economical production of nonwovens in a production environment in an in-line spunbond process, it is preferred that the belt speed be greater than that used in the above experiments (eg, up to approximately 600 mpm). The rapid (eg, in seconds) separation of bicomponent fibers achieved by the differential thermal shrinkage method of the present invention uses a nonwoven fabric formed by splitting the multicomponent fibers using a belt length that is compatible with the heating unit. And can be produced by the in-run spunbonding process at these high belt speeds. In doing so, the present invention makes inline spunbonding of splittable multicomponent fibers more economically attractive.

As can be seen from the above examples, fine denier nonwovens having desirable properties such as improved bulkiness, softness, drape and barrier properties provide ribbon-shaped multi-component fibers that provide a high degree of fiber segment separation. By using it, it can be manufactured by the in-line spunbonding method of the present invention. Having described preferred embodiments of the new and improved method and apparatus for in-line splitting of multicomponent fibers and forming nonwovens, in view of the teachings set forth herein,
Other modifications, variations or changes will be suggested to those skilled in the art. All such other modifications, variations or alterations are considered to be within the scope defined by the following claims.

[Brief description of the drawings]

FIG. 1 is a schematic view of an apparatus for performing a spunbond method using fiber ejection and in-line fiber division to form a nonwoven fabric.

FIG. 2 is a cross-sectional view of a bicomponent fiber having a circular cross-section and having wedge-shaped segments.

FIG. 3 is a view of a cross section of a hollow bicomponent fiber having a circular cross section.

FIG. 4 is a view of a cross section of a 5-segment component composite component fiber having a cross-shaped cross section.

FIG. 5 is a view of a cross section of a 9-segment component composite component fiber having a cross-shaped cross section.

FIG. 6 is a view showing a cross section of a 10-segment component composite component fiber having a ribbon-like shape.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B01D 39/16 B01D 39/16 A B29C 47/14 B29C 47/14 D04H 1/50 D04H 1/50 3 / 16 3/16 // D01F 8/04 D01F 8/04 (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE), OA (BF, BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, KE) , LS, MW, SD, SZ, UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AL, AM, AT, AU, AZ, BA, BB, B , BR, BY, CA, CH, CN, CU, CZ, DE, DK, EE, ES, FI, GB, GE, GH, GM, HU, ID, IL, IS, JP, KE, KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MD, MG, MK, MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI SK, SL, TJ, TM, TR, TT, UA, UG, US, UZ, VN, YU, ZW (72) Inventor Harris, Frank O. United States, Texas 37857, Rogersville, Route 1, Box 970 (72) Dugan, Jeffrey Scott United States, Tennessee 37650, Irwin, Fishery Loop Road 109 F-term (reference) 4D019 AA03 BA13 BB03 BC05 BC13 CB06 DA02 DA05 DA06 4F207 AA11 AA24 AG01 AH63 KA01 KA17 KB2 1 KK74 KL64 KL91 4L041 AA08 BA34 BA59 BD06 BD07 BD11 BD20 CA12 CA38 DD01 DD10 DD14 DD21 EE13 EE20 4L047 AA14 AA21 AA27 AB08 BA08 CB02 CB10 CC03 CC12

Claims (100)

[Claims] 1. A method of forming a nonwoven fabric from a method using fiber ejection and in-line fiber division, comprising: a first method in which each fiber has a relative difference in heat shrinkability. And an array of multi-component fibers consisting of a second material is ejected and deposited on a moving surface of the array of multi-component fibers to form a web, and heat is applied to said web to produce a first material. Between the segment of the multi-component fiber composed of the second component and the segment of the multi-component fiber composed of the second material due to the difference in heat shrinkage between the first and second materials. To form 2. The method according to claim 1, wherein the step of processing comprises joining the web. 3. The method according to claim 1, wherein the first and second materials have a difference in heat shrink of approximately at least 10%. 4. The method according to claim 1, wherein the step of applying heat comprises blowing air, steam or a combination of hot air and steam through the web. 5. The method according to claim 1, wherein the step of applying heat includes applying radiant heat to the web. 6. The method according to claim 1, wherein said first and second materials are non-hydrophilic. 7. The method according to claim 1, wherein said discharging step comprises forming multicomponent fibers as ribbon-shaped fibers. 8. The method according to claim 7, wherein the ribbon-shaped fibers have segments of a first material sandwiched between segments of a second material. 9. The method according to claim 8, wherein the ribbon-shaped fibers alternate between segments of the first material and segments of the second material. 10. The method of claim 1, wherein the discharging step forms a multi-component fiber having a cross-shaped cross-section, and wherein a central segment comprising a first material and a plurality of radiating segments comprising a second material comprise a central segment. 2. The method according to claim 1, comprising extending radially outwardly from the outer side. 11. The multi-component fiber formed in the discharging step further includes a plurality of radial segments made of a first material and radially outwardly extending from the plurality of radial segments made of a second material. The method according to claim 10. 12. The step of applying heat includes passing the web through a heating unit at a rate that allows the segments of the multicomponent fibers of a portion of the web to be separated while the portion of the web receives heat from the heating unit. 2. The method according to claim 1, comprising moving the object. 13. The method according to claim 12, wherein said portion of the web receives heat from said heating unit for less than about 1 second. 14. The method according to claim 1, wherein the segmental heat shrinkage difference of a portion of the web and the resulting fiber separation is substantially completed by the application of heat in less than about 1 second. 15. The method according to claim 1, wherein said discharging step comprises discharging a multicomponent fiber consisting of polypropylene and polyethylene terephthalate modified with isophthalic acid and a powdered transesterification inhibitor. 16. The method according to claim 1, further comprising thinning the ejected arrayed multi-component fibers prior to depositing the array of multi-component fibers on a moving surface. 17. The method according to claim 16, wherein said thinning step comprises drawing multicomponent fibers through an aspirator. 18. The method according to claim 16, wherein said thinning step comprises using at least one godet roll to attract or relax the multicomponent fibers. 19. The method of claim 1, wherein applying heat to the web causes the multicomponent fibers to crimp.
By way. 20. The method according to claim 1, wherein substantial separation of the segments of the multicomponent fiber does not occur prior to applying heat to the web. 21. The processing step comprises heating a web to a temperature at which a segment formed from one of the first and second materials begins to melt and adhere to an adjacent segment. 2. The method according to claim 1, which comprises passing through air. 22. A method of forming a nonwoven fabric from a method using fiber ejection and in-line fiber division, comprising: a first method in which each fiber has a relative difference in heat shrinkability. And an array of multi-component fibers made of the second material is discharged, and heat is applied to the web to form a segment of the multi-component fiber made of the first material and a segment of the multi-component fiber made of the second material. A heat shrinkage difference between the first and second materials, causing separation, depositing an array of multicomponent fibers on the moving surface, forming a web, and processing the web. To form a nonwoven fabric. 23. The method according to claim 22, wherein the step of processing includes joining the web. 24. The method according to claim 22, wherein the first and second materials have a heat shrink difference of at least about 10%. 25. The method according to claim 22, wherein said applying step comprises blowing air, steam or a combination of hot air and steam through the web. 26. The method according to claim 22, wherein said applying step comprises applying radiant heat to the web. 27. The method according to claim 22, wherein said first and second materials are non-hydrophilic. 28. The method according to claim 22, wherein said discharging step comprises forming multi-component fibers as ribbon-shaped fibers. 29. The method according to claim 28, wherein the ribbon-shaped fibers are segments of a first material sandwiched between segments of a second material. 30. The method according to claim 29, wherein the ribbon-shaped fibers are interleaved with segments of the first material and segments of the second material. 31. A method according to claim 31, wherein the discharging step forms a multi-component fiber having a cross-shaped cross-section made up of a plurality of radial segments, wherein the multi-component fiber is made of a central segment made of a first material. 23. A method according to claim 22, comprising a second segment and a second segment, said segments extending radially outward from a central segment. 32. The plurality of component fibers formed in the discharging step further include a plurality of radial segments made of a first material and radially outward from the plurality of radial segments made of a second material. 32. The method according to claim 31, comprising: 33. The separation of the fibers resulting from the difference in heat shrinkage of the segment at one point along the multi-component fiber is completed with the application of heat substantially less than one second.
By way. 34. The method according to claim 22, wherein said discharging step comprises discharging multicomponent fibers of polypropylene and polyethylene terephthalate modified with isophthalic acid and a powdered transesterification inhibitor. 35. The method according to claim 22, further comprising comminuting the discharged arrayed multicomponent fibers prior to depositing the array of multicomponent fibers on a moving surface. 36. The method according to claim 35, wherein said thinning step comprises drawing multicomponent fibers through an aspirator. 37. The method according to claim 36, wherein the aspirator applies hot air and / or steam to the array of multi-component fibers to cause a differential thermal shrinkage of the multi-component fiber segments up to the moving surface. 38. The method according to claim 35, wherein the thinning step comprises using at least one godet to pull or relax the array of multicomponent fibers. 39. The method according to claim 38, wherein said at least one godet imparts heat to the array of multi-component fibers to create a differential heat shrink and separate. 40. The application of heat to the web causes the multicomponent fibers to crimp.
Method according to 2. 41. The processing step comprises heating a web to a temperature at which a segment formed from one of the first and second materials begins to melt and adhere to an adjacent segment. 23. A method according to claim 22 comprising passing air coupling. 42. An apparatus comprising the following means for forming a nonwoven fabric by a method using fiber ejection and fiber splitting in-line: each having a relative difference in heat shrinkage from a first and a second material. A spin pack having a spinneret formed with an array of spinning holes for discharging an array of multicomponent fibers, which moves relative to the spinneret and receives an array of multicomponent fibers discharged from the spinning hole. A web forming surface on which a fiber web is formed; a first and a second component fiber segment comprising a first component material segment and a second component segment segment; A heating unit formed to apply heat to the fibrous web causing a difference in heat shrinkage of the second material; and a web processing means for forming a nonwoven fabric. 43. The apparatus according to claim 42, wherein said spinneret discharges multicomponent fibers of first and second materials having a heat shrink difference of at least about 10%. 44. The apparatus according to claim 42, wherein said processing means is an apparatus comprising means for bonding a web to form a spunbond fabric. 45. The web passing means wherein the means for bonding heats the web to a temperature at which a segment formed from one of the first and second materials begins to fuse and bond adjacent segments. 45. The device according to claim 44, which is a means for performing a heat connection. 46. The apparatus according to claim 42, wherein said spinneret discharges a composite component filament comprising first and second materials which are non-hydrophilic materials. 47. The apparatus according to claim 42, wherein said spinneret is configured to discharge a ribbon-shaped multicomponent fiber from a spinning hole. 48. The apparatus according to claim 47, wherein the ribbon-shaped bicomponent fibers ejected from the spinneret sandwich a first material between segments of a second material. 49. The composite component fiber in the form of ribbon discharged from the spinneret has segments of the first material and segments of the second material alternately arranged.
The device according to 8. 50. The spinneret according to claim 1, wherein the spinneret is configured to discharge a multi-component fiber having a cross-shaped cross-section, and a central segment made of a first material and a radially arranged central segment made of a second component. 43. The apparatus of claim 42, comprising a plurality of radial segments extending radially from the. 51. The multi-component fiber formed in the discharging step further includes a plurality of radial segments made of a first material and radially outwardly extending from the plurality of radial segments made of a second material. An apparatus according to claim 50. 52. The web forming surface wherein the fibrous web separates the heating unit while the multi-component fiber segments of a portion of the fibrous web receive heat from the portion of the fibrous web receiving heat from the heating unit. 43. The apparatus according to claim 42, wherein the apparatus moves relative to the heating unit so as to move through the heating unit at a speed that allows the heating unit to move. 53. The apparatus of claim 52, wherein said heating unit radiates heat to a portion of the web for substantially less than one second. 54. The method according to claim 42, wherein the heating unit substantially completes the differential thermal shrinkage of the multi-component fiber segment of a portion of the web by applying heat to the portion of the web for a time of about 1 second or less. apparatus. 55. The apparatus according to claim 42, wherein said heating unit blows hot air and / or steam through the web. 56. The apparatus according to claim 42, wherein said heating unit applies radiant heat to said web. 57. The method according to claim 42, wherein said spinneret discharges multicomponent fibers consisting of polypropylene and polyethylene terephthalate modified with isophthalic acid and a powdered transesterification inhibitor. 58. An arrayed multi-component fiber discharged from said spinneret prior to depositing the arrayed multi-component fiber on said web forming surface, wherein an aspirator is disposed between said spinneret and said web forming surface. 43. The apparatus according to claim 42, wherein 59. The apparatus according to claim 42, further comprising at least one godet for drawing or relaxing the array of multicomponent fibers. 60. A method using fiber splitting that is performed in-line with fiber ejection;
An apparatus for forming a nonwoven fabric comprising: a spinneret having an array of spinning holes for discharging an array of multicomponent fibers each having a relative difference in thermal shrinkage, each array comprising a first and a second material. A spin pack that moves relative to the spinneret and is provided to receive an array of multicomponent fibers ejected from the spinning holes, and a web forming surface that forms a fiber web on that surface; Prior to deposition on the web forming surface, the first and second materials are arranged such that segments of the multi-component fibers of the first material are separated from segments of the multi-component fibers of the second segment. A heating unit formed to apply heat to the array of multi-component fibers in order to cause a difference in thermal shrinkage, and a web processing means for forming a nonwoven fabric. 61. The apparatus according to claim 60, wherein said spinneret discharges multicomponent fibers of first and second materials having a heat shrink difference of at least about 10%. 62. The apparatus according to claim 60, wherein said processing means is an apparatus comprising means for bonding a web to form a spunbond fabric. 63. The web passing means wherein said means for bonding heats the web to a temperature at which a segment formed from one of said first and second materials begins to fuse and bond adjacent segments. 63. The device according to claim 62, which is a means for performing a pneumatic connection. 64. The apparatus according to claim 60, wherein said spinneret discharges multicomponent fibers of first and second materials which are non-hydrophilic materials. 65. The apparatus according to claim 60, wherein said spinneret is configured to discharge a ribbon-shaped composite component fiber from a spinning hole. 66. The apparatus according to claim 65, wherein the ribbon-shaped bicomponent fibers ejected from the spinneret sandwich a first material between segments of a second material. 67. The ribbon-shaped composite component fiber discharged from the spinneret has segments of a first material and segments of a second material alternately arranged.
The device according to 6. 68. A spinneret as defined above for discharging multi-component fibers having a cross-shaped cross section, wherein a central segment made of a first material and a central segment made of a second component are arranged radially. 61. The apparatus of claim 60, comprising a plurality of radial segments extending radially from the. 69. The multi-component fiber formed in the discharging step further includes a plurality of radial segments made of a first material and radially outwardly extending from the plurality of radial segments made of a second material. 70. The apparatus according to claim 68. 70. The heating unit applies heat at a point along the multicomponent fiber for less than about 1 second to reduce the heat shrinkage difference of the segments of the multicomponent fiber at one point along the multicomponent fiber. 61. The device of claim 60, wherein the device is substantially complete. 71. Apparatus according to claim 60, wherein said heating unit blows hot air and / or steam through the multicomponent fibers. 72. The apparatus according to claim 60, wherein said heating unit applies radiant heat to said web. 73. The method according to claim 60, wherein said discharging means comprises discharging a multicomponent fiber comprising polypropylene and polyethylene terephthalate modified with isophthalic acid and a powdered transesterification inhibitor. 74. An arrayed multicomponent fiber ejected from said spinneret prior to depositing the arrayed multicomponent fibers on said webforming surface, further comprising an aspirator disposed between said spinneret and said web forming surface. The device according to claim 60, wherein the device comprises: 75. The aspirator used as a heating unit, wherein the aspirator applies hot air and / or steam to the array of multicomponent fibers to cause a differential thermal shrinkage of the multicomponent fiber segments up to the moving surface. 75. A method according to claim 74. 76. The apparatus according to claim 60, further comprising using at least one godet to pull or relax the array of multicomponent fibers. 77. The apparatus according to claim 76, wherein said at least one godet is used as a heating unit and applies heat to an array of multi-component fibers to cause a differential thermal shrinkage prior to reaching a web forming surface. 78. A non-woven fabric comprising: a first fiber segment composed of a first material discharged as a component of a multi-component fiber fiber, wherein the non-woven fabric is manufactured by a method of dividing the fiber in-line with the discharge of the fiber. And a second fiber segment comprising a second material discharged as a component of the bicomponent fiber and exhibiting heat shrinkage different from the heat shrinkage of the first sitting, wherein the first and second segments are induced by heating. Being at least partially separated from the second fiber segment by the applied thermal contraction differential. 79. The nonwoven fabric according to claim 78, wherein said fabrics are joined to form a spunbond fabric. 80. The nonwoven fabric according to claim 79, wherein said fabric is air bonded through at least partially melting one of said first and second fiber segments. 81. The nonwoven fabric according to claim 78, wherein said second material has a heat shrink that is at least about 10% different from the heat shrink of the first material. 82. The nonwoven fabric according to claim 78, wherein said first and second materials are non-hydrophilic. 83. The nonwoven fabric according to claim 78, wherein said first material comprises polypropylene and said second material comprises polyethylene terephthalate modified with isophthalic acid and a powder transesterification inhibitor. 84. The nonwoven fabric according to claim 78, wherein at least one of said first and second materials comprises a fluoropolymer compound and / or silicon. 85. The nonwoven fabric according to claim 78, wherein at least one of said first and second materials comprises a swellable blowing agent. 86. The nonwoven fabric according to claim 78, wherein said first and second fiber segments are ribbon-shaped fiber segments. 87. The fiber according to claim 86, wherein said ribbon-shaped fiber is a bicomponent fiber comprising first fiber segments and second fiber segments arranged alternately. 88. The method according to claim 88, wherein the first and second fiber segments are segments of a bicomponent fiber having a cross-shaped cross-section, the center segment comprising a first fiber segment and the radial segment comprising a second fiber segment. 8. A segment comprising a plurality of radial segments extending radially from a central segment.
The device according to 8. 89. The multi-component fiber is further a first fiber segment, wherein the second component fiber is a second fiber segment.
88. A plurality of radial segments comprising a first segment extending radially outward from a plurality of radial segments comprising a plurality of fiber segments.
By nonwoven fabric. 90. A product comprising a nonwoven fabric according to claim 78 selected from the group of disposable absorbents, medical barrier fabrics, filtration materials, and padding. 91. A multi-component fiber discharged from a hole in a spinneret comprising: a first segment comprising a first material component; and a second segment having a heat shrinkage different from that of the first material component. A second segment comprising a component of the first component, wherein the first segment can be separated from the second segment by the application of radiant heat causing a thermal contraction difference between the first and second component materials. 92. The multicomponent fiber according to claim 91, wherein said second material has a heat shrink that is at least about 10% different than the heat shrink of the first material. 93. The multicomponent fiber according to claim 91, wherein said first and second materials are non-hydrophilic. 94. The multi-component fiber is a ribbon-shaped fiber.
By multi-component fiber. 95. The multicomponent fiber according to claim 91, wherein said ribbon-shaped fibers comprise first fiber segments and second fiber segments arranged alternately. 96. The multi-component fiber has a cross-shaped cross-section, a central segment comprising a first fiber segment and a radial segment comprising a second fiber segment and being outward from the central segment. 92. The apparatus according to claim 91, comprising a plurality of radial segments extending radially toward the first. 97. The multi-component fiber is further a first fiber segment, wherein the second component fiber is a second fiber segment.
And a plurality of first radial segments extending radially outward from the plurality of radial segments.
6. The multicomponent fiber according to 6. 98. The multicomponent fiber according to claim 91, wherein said first material component comprises polypropylene and said second material component comprises polyethylene terephthalate modified with isophthalic acid and a powdered transesterification inhibitor. 99. The multicomponent fiber according to claim 91, wherein at least one of said first and second materials comprises a fluoropolymer compound and / or silicon. 100. The multicomponent fiber according to claim 91, wherein at least one of said first and second materials comprises a swelling blowing agent.