JP2006514177A - Fiber structure containing cellulose fiber and synthetic fiber and method for producing the same - Google Patents

Abstract

  A monolithic fiber structure (100) having at least two layers, wherein at least one layer of the structure comprises long cellulose fibers (103), at least one layer comprising short cellulose fibers (102) and synthetic fibers (101). ) And a method of making the fiber structure.

Description

  The present invention relates to a fiber structure including a combination of cellulose fiber and synthetic fiber, and a method for producing the same, and more specifically, at least one layer including short cellulose fiber mixed with synthetic fiber and long cellulose. And a fiber structure having at least one layer predominantly comprising fibers.

  Fibrous structures such as paper webs are well known in the art and are commonly used today for paper towels, toilet paper, facial tissue, napkins, wet towels, and the like. Typical tissue paper consists mostly of cellulosic fibers, predominantly wood. Despite the wide variety of cellulosic fibers, such fibers generally have a high dry modulus and a relatively large diameter that can cause their bending stiffness to be greater than desired for some applications. is there. In addition, cellulose fibers can have a relatively high stiffness when dried, which can adversely affect the flexibility of the product, and can reduce the absorbency of products obtained with a low stiffness when wet.

  To form a web, the fibers in a typical disposable paper product are bonded together by a chemical reaction, often only hydrogen bonds that occur naturally between the hydroxyl groups of the cellulose molecule. . Enhancement additives can be used if greater temporary or permanent wet strength is desired. These additives usually act either by covalently reacting with cellulose or by forming a protective molecular coating around existing hydrogen bonds. However, additives can also create a relatively stiff and inelastic bond, adversely affecting the softness and absorbent properties of the product.

  Using synthetic fibers with cellulosic fibers can help overcome some of the limitations previously described. Synthetic polymers can be formed into fibers having a wide range of diameters, including very small fibers. Furthermore, the synthetic fiber can be formed to have a lower elastic modulus than the cellulose fiber. Thus, synthetic fibers can be made to have very low bending stiffness, which facilitates good product flexibility. Furthermore, the functional cross section of the synthetic fiber can be micro-engineered. Synthetic fibers can also be designed to maintain elastic modulus when wet, so webs made with such fibers may be resistant to crunch during absorption operations. Furthermore, the use of synthetic fibers can help promote web formation and / or uniformity thereof. Therefore, by using heat-bonded synthetic fibers in tissue products, joined by water-resistant high-strength bonds (good for flexibility and wet strength) (good for flexibility) A strong network of highly flexible fibers results. However, synthetic fibers can be relatively expensive compared to cellulose fibers. Thus, it is desirable to include only the amount of synthetic fiber necessary to obtain the desired effect that the fiber provides. Mixing short cellulose fibers with synthetic fibers can help promote the dispersion of the synthetic fibers, thus requiring fewer (or less) synthetic fibers than if no short cellulose fibers were mixed in the web. We have found that many of the effects of synthetic fibers can be provided individually or in combination with each other.

  Accordingly, it would be advantageous to provide an improved fiber structure comprising a combination of cellulose fibers and synthetic fibers and a method for making such a fiber structure. It would also be advantageous to provide a product having synthetic fibers concentrated within a desired portion of the resulting web and a method that allows such non-random placement of such fibers. It would also be advantageous to have a product comprising short cellulosic and synthetic fibers disposed in at least one layer and longer fibers predominantly disposed in one or more other layers, and a method of making the product It is.

  To address the problems associated with the prior art, a monolithic fiber structure having at least two layers, wherein at least one layer of the structure comprises long cellulose fibers and at least one layer comprises a mixture of short cellulose fibers and synthetic fibers We invented the body.

  Furthermore, we have invented a method of making a fibrous structure, the method comprising: synthetic fiber and short cellulose fiber so as to form one or more layers comprising a mixture of synthetic fiber and short cellulose fiber Supplying a mixture of a plurality of long cellulose fibers on the mixture of synthetic fibers and short cellulose fibers so as to form one or more layers predominantly comprising a long cellulose fiber stage. And forming a monolithic fiber structure comprising one or more layers comprising a mixture of synthetic and short cellulose fibers and one or more layers predominantly comprising long cellulose fibers. .

  As used herein, the following terms have the following meanings.

  "Average cellulose fiber width" is the cellulose as measured by the Kajaani FiberLab facility available from Metso Automation Kajaani Ltd., Narcos, GA. The average fiber width of the fiber.

“Average synthetic fiber diameter” is the average fiber diameter of synthetic fibers derived from the following formula: average synthetic fiber diameter = square root (mass denier × K / density), where mass denier is the mass of denier of the fiber Part (grams) only (for example, 3 denier fiber is 3 g / 9000 m but the mass denier of the fiber is 3 g) and K = 141.5. The constant K = 141.5 is for cylindrical fibers. For non-cylindrical fibers, a different constant K ₁ must be recalculated using the non-cylindrical cross-sectional area of the fiber. In this way, the fiber diameter has units of micrometers.

  “Fiber roughness” is defined as the weight per unit length of fiber expressed as milligrams per 100 meters, as shown by the TAPPI method T234cm-02.

  “Co-bonded fibers” are fused or bonded together or otherwise bonded together by melting, bonding, wrapping, chemical or mechanical bonding, at least partially while retaining their individual fiber properties. Means two or more fibers.

“Fiber length ratio” means TAPPI T271 om for length weighted average fiber length (L _L ), measured using a Kajaani FiberLab facility, as described in the examples below. 02 is the ratio of length-weighted average fiber lengths of different fiber types as measured by the method set forth in paragraph 8.2.

  “Long cellulosic fibers” or “long cellulosic fibers” are generally fibers from coniferous sources and have a longest dimension length of greater than about 2 mm when measured in a flat and straight shape. Non-limiting examples of long cellulose fibers can be obtained from pine, spruce, fir and cedar trees.

  The “PTP coefficient” is the ratio of the average synthetic fiber diameter to the average cellulose width, as will be described in more detail in the examples below. Without being bound by theory, it is believed that the PTP coefficient is related to the tendency to form a functional bond between synthetic and cellulose fibers. This favorable binding tendency can result from a more uniform distribution of the synthetic fibers within the mixture of synthetic and short cellulose fibers.

  “Redistribution” means that at least some of the plurality of fibers contained within the single fiber structure of the present invention at least partially melt, move, or move their initial in-web position, state, and / or shape, It means shrinking and / or changing in other ways.

  “Short cellulosic fibers” or “short cellulosic fibers” are fibers that usually come from hardwood and have a longest dimension length of less than about 2 mm when measured in a flat and straight shape. In certain examples, the short cellulose fibers may be less than about 1 mm long. Non-limiting examples of short cellulose fibers can be obtained from Eucalyptus, Acacia, and Maple trees.

  A “single fiber structure” is a configuration that includes a plurality of cellulose fibers and synthetic fibers that are intertwined or otherwise joined together to form some predetermined microscopic shape characteristic. Forming a sheet product having physical properties and appearance properties. Cellulose and / or synthetic fibers may be laminated or arranged differently within a single fiber structure.

  The fiber structure of the present invention can take many different forms, but generally comprises at least one layer having synthetic fibers mixed with cellulose fibers and at least one adjacent layer comprising cellulose fibers. More specifically, in one embodiment of the present invention, the fiber structure can include one or more layers comprising synthetic fibers mixed with short cellulose fibers, as described herein. The synthetic fiber / short cellulose fiber mixture may be relatively homogeneous in that the different fibers are dispersed generally randomly and throughout the layer, or the synthetic fibers and / or cellulose fibers are generally non-random. It may be more structural as it is arranged. In addition, one or more layers of mixed cellulose fibers and synthetic fibers may be formed or applied by any type of operation during or after web creation to predetermine the mixed synthetic fibers and cellulose fibers. Or other non-random pattern layer (s) may be provided.

  The fiber structure can include various fiber types. For example, the structure can include naturally occurring fibers such as fibers from hardwood sources, coniferous sources, or other non-wood plants. Non-limiting examples of suitable natural fibers are identified in Table 1. Other sources of natural fiber from plants include albardine, esparto, wheat, rice, corn, sugar cane, papyrus, burlap, reed, sabia, raffia, bamboo, sidal, kenaf, Examples include, but are not limited to, Abaca, Sun Hemp, Cotton, Cannabis, Flax, and Lamy. Still other natural fibers may include fibers from other natural non-vegetable sources such as down, feathers, silk, and the like. Natural fibers may be mechanically or chemically treated or otherwise modified to provide desirable properties, or may be in a form that is generally similar to that found in nature. For the developments described herein, mechanical and / or chemical manipulation of natural fibers does not exclude them from the category considered natural fibers.

  The fibrous structure can also include any suitable synthetic fiber. The synthetic fiber can be any material selected from the group consisting of, for example, polyolefins, polyesters, polyamides, polyhydroxyalkanoates, polysaccharides, and any combination thereof. More specifically, synthetic fiber materials are polypropylene, polyethylene, poly (ethylene terephthalate), poly (butylene terephthalate), poly (1,4-cyclohexylenedimethylene terephthalate), isophthalic acid copolymers, ethylene glycol copolymer. , Polycaprolactone, poly (hydroxyetherester), poly (hydroxyetheramide), polyesteramide, poly (lactic acid), polyhydroxybutyrate, starch, cellulose, glycogen, and any combination thereof Can be done. In addition, synthetic fibers can be composed of a single component (ie, a single synthetic material or a mixture that assembles the entire fiber), two components (ie, the fibers are divided into regions, and regions are divided into two different synthetic materials or their Mixture), or multi-component fibers (ie, the fibers are divided into regions, where the regions include two or more different synthetic materials or mixtures thereof), or any combination thereof . Also, any or all of the synthetic fibers may be treated before, during, or after the process of the present invention to change any desired properties of the fibers. For example, in certain embodiments, it may be desirable to treat synthetic fibers before or during the papermaking process to make them more hydrophilic, more wettable, and the like.

  In certain embodiments of the present invention, it may be desirable to have a specific combination of fibers to provide the desired properties. For example, it may be desirable to have fibers of a certain length, width, fiber roughness, or other characteristics combined in certain layers or separated from each other. The fibers can individually have certain desired properties. For example, the long cellulose fibers can have any desired property consistent with the definitions set forth above. In certain embodiments, the long cellulose fibers have an average cellulose fiber width of less than about 50 μm, less than about 40 μm, less than about 30 μm, less than about 25 μm, or an average cellulose fiber width within the range of about 10 to about 50 μm. It may be desirable. Further, it may be desirable for the short cellulose fibers to have an average cellulose fiber width of less than about 25 μm, less than about 20 μm, less than about 18 μm, or an average cellulose fiber width falling within the range of about 8 to about 25 μm. For synthetic fibers, for example, the average fiber diameter is greater than about 10 μm, greater than about 15 μm, greater than about 25 μm, greater than about 30 μm, or the average synthetic fiber diameter falls within the range of about 10 to about 50 μm, It may be desirable to have certain characteristics.

  Also, the fibers in one or more layers are mixed so that the specific fibers in one or more layers have a fiber length ratio within a specific range, i.e., a PTP coefficient as defined herein. May be desirable. In certain embodiments, the fiber length ratio of synthetic fiber 101 to short cellulose fibers 102 in mixed layer 105 is greater than about 1, greater than about 1.25, greater than about 1.5, or greater than about 2. Other minimum limits on fiber length ratio are also considered, such as a range extending from about 1 to about 20 where any upper or lower limit falls within that range. In some embodiments, the mixed layer 105 may also have a PTP coefficient greater than about 0.75, greater than about 1, greater than about 1.25, greater than about 1.5, or greater than about 2, although any upper or Other minimum limits for the PTP coefficient are also considered, such as a range that extends from about 0.75 to about 10 that also falls within the lower limit. The mixed layer may also desirably have a fiber roughness value of less than about 50 mg / 100 m, less than about 40 mg / 100 m, less than about 30 mg / 100 m, or less than about 25 mg / 100 m, but about 5 mg Other maximum limits on fiber roughness are also considered, such as a range extending from / 100 m to about 75 mg / 100 m.

  As can be seen in the following examples, the present invention provides webs and methods of forming webs having surprising properties. For example, the fiber structure of the present invention, alone or in combination, provides an advantage over currently available webs, for example in the areas of flexibility, better and / or more uniform formation, and wet rupture. And the refining of cellulose fibers required to obtain the same properties in the resulting web is reduced, thus providing a manufacturing effect by increasing the production rate.

  As described in Example 1, a two-ply paper web containing NSK and eucalyptus fibers is made. The resulting web has a wet burst strength of about 374 g. In Example 2, a two-ply paper web is made in the same way as Example 1, but with 10% by weight of eucalyptus fibers replaced with 10% by weight of synthetic two-component polyester fibers (3 mm long). The synthetic / eucalyptus mixture has a fiber length ratio of 4.2, a PTP factor of 1.2, and a fiber roughness value of 11.0 mg / 100 m. The fibrous structure obtained in Example 2 has a wet burst strength of about 484 g, which is higher than the wet burst strength of the typical product made in Example 1. In Example 3, a two-ply paper web is made in the same manner as in Example 1, but with 5% by weight of eucalyptus fibers replaced with 5% by weight of synthetic two-component polyester fibers (6 mm long). The synthetic / eucalyptus mixture has a fiber length ratio of 8.4, a PTP factor of 1.2, and a fiber roughness value of 11.6 mg / 100 m. The fiber structure obtained in Example 3 is an even lower weight synthetic fiber, but has a wet burst strength of about 472 g, which is still much higher than the wet burst strength of the product of Example 1. Thus, it can be seen that the structure of the present invention and the method of making the structure provide a surprising means to enhance wet rupture of the web with the use of small weight percent synthetic fibers mixed with short cellulose fibers. it can. Of course, these examples should not be considered as the only examples of the effects of the present invention, and other examples are possible, and such other examples will occur to those skilled in the art based on the teachings herein. It should be understood that this can be done more easily. Moreover, any such additions or modifications are intended to be within the scope of the present invention, even if that particular effect or characteristic is not described in detail herein.

  The process of the present invention for making the fibrous structure 100 is generally from the point of forming a web having a plurality of synthetic fibers 101 mixed in a plurality of short cellulose fibers 102 and arranged in one or more layers. Explained. The structure also generally includes one or more layers that contain longer fibers, usually long cellulose fibers 103. In one embodiment, the mixed layer 105 comprising synthetic fibers 101 and short cellulose fibers 102 can be formed to be at least partially arranged in a generally non-random pattern. Although the layers 106 of long fibers 103 are typically arranged generally randomly (eg, as shown in FIG. 9), such layers 106 may be patterned or otherwise non-randomly arranged. May be. The method and apparatus of the present invention comprises a plurality of long cellulose fibers 103 arranged in a generally non-random pattern and a plurality of randomly arranged within layer 105 (eg, as shown in FIG. 9A) mixed together. It is also suitable for forming a web having synthetic fibers 101 and short cellulose fibers 102.

  In an embodiment in which the mixture 104 of synthetic fibers 101 and short cellulose fibers 102 is non-randomly arranged, the method supplies the mixture of synthetic fibers 101 and short cellulose fibers 102 onto a forming member, and A step of causing the mixture 104 of short cellulose fibers 102 to be at least partially disposed within a predetermined region or groove, and a plurality of long cellulose fibers 103 substantially randomly on the mixture 104 of synthetic fibers and short cellulose fibers 102. And forming a monolithic fiber structure comprising a randomly placed cellulose fiber and a non-randomly placed synthetic fiber / short cellulose fiber mixture 104.

  In an embodiment in which the mixture 104 of synthetic fibers 101 and short cellulose fibers 102 is arranged approximately randomly and the long cellulose fibers 103 are non-randomly arranged, the method supplies a plurality of long cellulose fibers onto the forming member. A step of arranging the long cellulose fibers 103 at least partially in a predetermined region of the forming member, that is, a groove, and a random mixture of the short cellulose fibers 102 and the synthetic fibers 101 on the long cellulose fibers 103. And forming a monolithic fiber structure comprising non-randomly placed long cellulose fibers 103 and randomly placed synthetic fiber / short cellulose fiber mixture 104.

  FIG. 1 illustrates an exemplary embodiment of the continuous process of the present invention, in which an aqueous slurry 11 of fibers is deposited from a headbox 12 onto a forming member 13 to form an initial web 10. (However, this is just one of the myriad methods that can be used for the web of the present invention, including different methods such as similar methods with additional or fewer steps or air laying. The method can include a combination of one or more of these or other known methods for creating a web.) In this particular embodiment, the forming member 13 is supported by rolls 13a, 13b, and 13c. Then, the vehicle travels continuously in the direction of arrow A around these. The slurry 11 may include any number of different fiber types and may be deposited in multiple layers. In one embodiment, the slurry 11 includes at least one layer that includes a mixture 104 of synthetic fibers 101 and short cellulose fibers 102 as described herein. In addition, the slurry 11 can also include one or more layers of long cellulose fibers 103, as described herein. When it is desired that the mixture 104 of the short cellulose fibers 102 and the synthetic fibers 101 is formed in a non-random pattern, the mixture 104 is present in the forming member 13 at least a part of the mixture 104 (for example, in FIGS. 7 and 8). It may be deposited on the forming member 13 prior to the deposition of the long cellulose fibers 103 so as to go to a predetermined area such as the groove 53 (as shown). In some embodiments, more than one headbox 12 can be used and / or the mixture 104 is deposited on the forming member 13 and then transferred to a different forming member where it is then on the mixture 104. Long cellulose fibers 103 may be deposited.

  In one embodiment of the present invention, the mixture 104 of synthetic fibers 101 and short cellulose fibers 102 is supplied such that at least the synthetic fibers 104 are predominantly disposed in the grooves 53 of the forming member 13. That is, when the web 10 is formed, which exceeds half of the synthetic fiber 101, it is disposed in the groove 53. In certain embodiments, it is desirable for at least about 60%, about 75%, about 80%, or substantially all of the synthetic fiber 101 to be placed in the groove 53 when the web 10 is formed. In addition, the resulting product web 100 desirably includes a percentage of synthetic fibers 101 disposed in one or more layers. For example, a layer formed by fibers initially or closest to the forming member 13 may have a concentration of synthetic fibers 101 of greater than about 50%, greater than about 60%, or greater than about 75%. desirable. Alternatively, such a layer desirably has almost all, or some percentage of the mixture 104 of synthetic fibers 101 and short cellulose fibers 102. (A suitable method for measuring the percentage of a particular type of fiber in a web product layer is disclosed in US Pat. No. 5,178,729 (Bruce Janda, issued January 12, 1993). In addition, in some embodiments, the long cellulose fibers 103 are provided to be predominantly disposed in at least one layer adjacent to the mixture 104 of synthetic fibers 101 and short cellulose fibers 102. desirable. In another embodiment, it is desirable to be disposed in at least one layer of the web 100 of at least some percent of the long cellulose fibers 103, such as greater than about 55%, greater than about 60%, or greater than about 75%. . Usually, at least one layer of the long cellulose fibers 103 is arranged approximately randomly. Thus, the resulting web 100 is a non-random pattern of synthetic fibers 101 and / or synthetic fibers 101 bonded to one or more layers of long cellulose fibers 103 (eg, FIGS. 9 and 10) distributed generally randomly. And a mixture 104 of short cellulose fibers 102 can be provided. Furthermore, it is possible to form fiber structures having micro areas with different basis weights.

  The forming member 13 can be any suitable structure and is usually at least partially fluid permeable. For example, the forming member 13 can have a plurality of fluid permeable areas 54 and a plurality of fluid impermeable areas 55 as shown, for example, in FIGS. The fluid permeable area or opening 54 can extend through the thickness H of the forming member 13 from the web side 51 to the back side 52. In some embodiments, some of the fluid permeable areas 54 having openings, as described in US Pat. No. 5,972,813 (issued October 26, 1999 by Polat et al.), It may be “blind”, ie “closed”. The fluid permeable zone 54, whether open or blind, forms a groove 53 into which fibers can be directed. At least one of the plurality of fluid permeable areas 54 and the plurality of fluid impermeable areas 55 typically forms a pattern throughout the molding member 50. Such patterns can include random patterns or non-random patterns, and can be substantially continuous (eg, FIG. 2), substantially semi-continuous (eg, FIG. 4), separable (eg, FIG. 5), or any A combination of these can be used.

  The forming member 13 may have any suitable thickness H, and in fact, the thickness H can be varied throughout the forming member 13 as desired. Further, the groove 53 may be any shape or combination of different shapes and may have any depth D, which can vary throughout the forming member 13. The groove 53 can also have any desired volume. The depth D and volume of the groove 53 can be varied as desired to help ensure that the desired concentration of the synthetic fibers 101 and / or short cellulose fibers 102 is within the groove 53. In certain embodiments, it is desirable for the depth D of the groove 53 to be less than about 254 μm, or less than about 127 μm. Further, the amount of synthetic fibers 101 and / or short cellulose fibers 102 deposited on the forming member 13 is such that the desired ratio or percentage of the synthetic fibers 101 and / or short cellulose fibers 102 is a groove of a particular depth D or volume. It can be changed to be surely placed in 53. For example, in certain embodiments, sufficient synthetic fibers 101 or synthetic fibers 101 and short cellulose to substantially fill the grooves 53 so that the long cellulose fibers 103 are not substantially disposed within the grooves 53 during the web making process. It is desirable to provide a mixture 104 of fibers 102. In another embodiment, only enough synthetic fibers 101 and / or short cellulose fibers 102 to fill a portion of the groove 53 so that at least some of the long cellulose fibers 103 can also go into the groove 53. It is desirable to supply

  Some exemplary forming members 13 have a structure as shown in FIGS. 2-8 including a fluid permeable reinforcing element 70 and a pattern or framework 60 extending therefrom to form a plurality of grooves 53. be able to. In one embodiment, as shown in FIGS. 5 and 6, the forming member 13 can have a plurality of separable protrusions 61 coupled to or integral with the reinforcing element 70. The reinforcing element 70 generally serves to provide or facilitate integrity, stability, and durability. The reinforcing element 70 can be fluid permeable or partially fluid permeable, can have various embodiments and weave patterns, and can be made of a variety of materials, such as a plurality of interwoven yarns (Jacquard type and similar). Woven patterns), felts, plastics or other synthetic materials, nets, plates with multiple holes, or any combination thereof. Examples of suitable reinforcing elements 70 are US Pat. Nos. 5,496,624 (Stelljes et al., Issued 5 March 1996), 5,500,277 (Trokhan et al., 1996). Published 19 March), and 5,566,724 (issued 22 October 1996, Trokhan et al.). Alternatively, reinforcing elements 70 including jacquard type weaving can be used. Examples of belts are US Pat. Nos. 5,429,686 (issued July 4, 1995), US Pat. No. 5,672,248 (Wendt et al., September 30, 1997). Issued), 5,746,887 (Wendt et al., Issued May 5, 1998), and 6,017,417 (Wendt et al., Issued January 25, 2000). Can be found. In addition, various designs of jacquard weave patterns can be used as the forming member 13.

  An exemplary and preferred framework element 60 and method of applying the framework 60 to the reinforcing element 70 is described, for example, in U.S. Pat. No. 4,514,345 (Johnson, issued Apr. 30, 1985), 4,528. , 239 (Trokhann, issued on July 9, 1985), 4,529,480 (Trokhann, issued on July 16, 1985), 4,637,859 (Trokhan ( Trokhann), published on January 20, 1987), 5,334,289 (Trokhann, issued on August 2, 1994), 5,500,277 (Trokhann et al., 1996) (Issued 19 March), 5,514,523 (Trokhann et al., Issued May 7, 1996), 5,628,876 (Ayers et al., 13 May 1997) Issue) No. 5,804,036 (Phan et al., Issued on September 8, 1998), No. 5,906,710 (Trokhann, issued on May 25, 1999), No. 6,039, No. 839 (Trokhann et al., Issued on March 21, 2000), No. 6,110,324 (Trokhann et al., Issued on August 29, 2000), No. 6,117,270 (Trokhan) (Trokhann), issued on September 12, 2000), 6,171,447B1 (Trokhann, issued on January 9, 2001), and 6,193,847B1 (Trokhann, 2001) Issued on Feb. 27, 2007). Further, as shown in FIG. 6, the framework 60 may include one or an opening or hole 58 that extends through the framework element 60. Such a hole 58 is different from the groove 53 and, by using it, aids dewatering from the slurry or web and / or the fibers deposited on the framework 60 are fully introduced into the groove 53. Can help prevent you from moving to.

  Alternatively, the forming member 13 may include any other structure suitable for receiving fibers, including several patterns of grooves 53 into which the synthetic fibers 101 and / or short cellulose fibers 102 may be directed. Often this includes, but is not limited to, plaids, composite belts, and / or felts. In any case, the pattern or framework 60 may be separable or substantially separable as described above, may be continuous or substantially continuous, or semi-continuous or substantial. Semi-continuous. Certain exemplary forming members 13 that are generally suitable for use with the method of the present invention are US Pat. Nos. 5,245,025, 5,277,761, 5,443,691, 5,503,715, 5,527,428, 5,534,326, 5,614,061, and 5,654,076.

  US Pat. No. 5,580,423 (Ampulski et al., Issued December 3, 1996), No. 5,609,725 (Phan, 1997) when the forming member 13 includes a press felt. (Issued on March 11, 1997), No. 5,629,052 (issued on May 13, 1997), No. 5,637,194 (Ampulski et al., June 1997) Issued 10th), 5,674,663 (McFarland et al., Issued October 7, 1997), 5,693,187 (Ampulski et al., December 2, 1997) No. 5,709,775 (issued January 20, 1998), No. 5,776,307 (issued on July 7, 1998) , 5th No. 795,440 (Ampulski et al., Issued on August 18, 1998), No. 5,814,190 (Phan, issued on September 29, 1998), No. 5,817,377 (Trokhan et al., Issued October 6, 1998), 5,846,379 (Ampulski et al., Issued December 8, 1998), 5,855,739 (Ampleski) (Ampulski et al., Issued on Jan. 5, 1999) and 5,861,082 (Ampulski et al., Issued on Jan. 19, 1999). In an alternative embodiment, the forming member 13 can be implemented as a press felt according to the teachings of US Pat. No. 5,569,358 (Cameron, issued Oct. 29, 1996) or any other suitable structure. is there. Other structures suitable for use as the forming member 13 are described below in connection with the optional molded member 50.

  Using a vacuum device such as a vacuum device 14 disposed below the forming member 13 to apply a fluid pressure differential to the slurry disposed on the forming member 13 to promote at least partial dewatering of the initial web 10. Can do. This fluid differential pressure can also help the desired fibers, for example, the mixture 104 of synthetic fibers 101 and short cellulose fibers 102 to go into the grooves 53 of the forming member 13. Other known methods may be used in addition to or as an alternative to the vacuum device 14 to help dewater the web 10 and / or the fibers toward the grooves 53 of the forming member 13.

  If desired, the initial web 10 formed on the forming member 13 can be transferred from the forming member 13 to another structure such as a felt or molded member. The molded member is a structural element that can be used as a support for the initial web and as a forming unit for forming or “molding” a desired microscopic shape in the fibrous structure. The molded member may include any component having an ability to give a microscopic three-dimensional pattern to the structure generated on the upper side. The molded member may be a fixed plate, a belt, or a woven fabric such as a jacquard type. Single layer structures and multilayer structures comprising woven fabrics, bands, rolls (including patterns) are included without limitation.

  In the exemplary embodiment shown in FIG. 1, the molding member 50 is fluid permeable and is sufficient for the vacuum shoe 15 to pull the initial web 10 disposed on the forming member 13 away and adhere to the molding member 50. Apply proper vacuum pressure. 1 includes a belt that is supported by rolls 50a, 50b, 50c, and 50d and travels around these in the direction of arrow B. The molding member 50 has a side 151 that contacts the web and a back side 152 that faces the side 151 that contacts the web.

  The molded member 50 can take any suitable form and can be made of any suitable material. The molded member 50 may include any structure and may be made by any of the methods described herein in connection with the forming member 13, but the molded member 50 is limited to such structures and methods. Not. For example, the molding member 50 includes a resin frame 160 coupled to the reinforcing element 170 as shown in FIGS. 13 and 14, for example. In addition, various designs of jacquard weave patterns can be used as the molded member 50 and / or the compression surface 210. If desired, the molded member 50 may be a press felt or include it. Suitable press felts for use with the present invention include, but are not limited to, those described herein in connection with forming member 13.

  In some embodiments, the molded member 50 can have a plurality of fluid permeable areas 154 and a plurality of fluid impermeable areas 155, for example as shown in FIGS. A fluid permeable area or opening 154 extends through the thickness H 1 of the molded member 50 from the web side 151 to the back side 152. As described above with respect to the forming member 13, the thickness H1 of the molded member can be any desired thickness. Further, the depth D1 and volume of the groove 153 can be varied as desired. Further, one or more of the fluid permeable areas 154 including the openings may be “blind” or “closed” as described above with respect to the forming member 13. At least one of the plurality of fluid permeable areas 154 and the plurality of fluid impermeable areas 155 typically forms a non-random repeating pattern throughout the molded member 50. Such patterns can include random patterns or non-random patterns, and can include substantially continuous, substantially semi-continuous, separable, or any combination thereof. The portion of the reinforcing element 170 that coincides with the opening 154 in the molded member 50 provides support for fibers that flex into the fluid permeable area of the molded member 50 during the process of making the single fibrous structure 100. be able to. The reinforcing element can help prevent the fibers of the web being created from passing through the molded member 50, thereby reducing the occurrence of pinholes in the resulting structure 100. In another embodiment, the molded member 50 includes a plurality of base portions extending from a plurality of base portions, as taught by US Pat. No. 6,576,090 (issued June 10, 2003). A suspended portion can be included.

  When the initial web 10 is placed on the side 151 of the molding member 50 that contacts the web, the web 10 preferably conforms at least in part to the three-dimensional pattern of the molding member 50. Further, the cellulose fibers and / or synthetic fibers of the initial web 10 are adapted to the three-dimensional pattern of the molded member 50 to become a molded web (shown as “20” in FIG. 1), or Various means can be used to encourage. (It should be understood herein that the reference numbers “10” and “20” and the terms “initial web” and “molded web” can be used interchangeably.) Applying a fluid pressure difference to the fibers. For example, as shown in FIG. 1, the vacuum device 16 and / or 17 disposed on the back side 152 of the molding member 50 may be used to apply a vacuum pressure to the molding member 50 and eventually to a plurality of fibers disposed on the upper portion. Can be arranged. Under the influence of the fluid pressure difference ΔP1 and / or ΔP2 caused by the vacuum pressure of each of the vacuum devices 16 and 17, a part of the initial web 10 is deflected into the groove 153 of the molding member 50 and conforms to its three-dimensional pattern. Can do.

  By deflecting a portion of the initial web 10 into the groove 153 of the molding member 50, the density of the resulting pillow 150 formed in the groove 153 of the molding member 50 is compared to the density of the remainder of the molding web 20. Can be reduced. A region 168 that does not flex into the opening is later formed between the pressure surface 218 and the molded member 50, such as in a pressure nip formed between the surface 210 of the drying drum 200 and the roll 50c shown in FIG. (FIG. 11) The web 20 may be embossed by embossing. When indented, the density of region 168 may be even greater than the density of pillow 150. The plurality of pillows 150 may include symmetric pillows, asymmetrical pillows, or a combination thereof.

  Different heights of the micro regions can also be formed by the molding member 50 having a three-dimensional pattern with different depths or heights. Such three-dimensional patterns having different depths / heights can be created by sanding preselected portions of the molded member 50 and reducing their height. Alternatively, a three-dimensional mask having recesses / projections with different depths / heights can be used to form corresponding frameworks 160 with different heights. Other conventional techniques for forming surfaces with different heights can also be used for the applications described above. It should be understood that the techniques described herein for forming the molded member are also applicable to forming the forming member 13.

  In certain embodiments, it may be desirable to shorten the fiber structure 100 of the present invention during creation. For example, the molding member 50 may be configured to have a linear velocity that is slower than the linear velocity of the forming member 13. Such a speed difference at the transfer point from the forming member 13 to the molding member 50 can be used to achieve “microshrinkage”. A detailed example of wet microshrinkage is described in US Pat. No. 4,440,597. Such wet microshrinking can cause a web having a low fiber concentration to move from any first member (eg, a perforated forming member) to any second member (eg, an eye) that moves at a slower rate than the first member. Transfer to a rough woven fabric or the like). The speed difference between the first member and the second member can vary according to the desired final properties of the fiber structure 100. Other patents describing methods for achieving microshrinkage include, for example, US Pat. Nos. 5,830,321, 6,361,654, and 6,171,442.

  The fiber structure 100 may additionally or alternatively be shortened after it has been formed and / or after it has been substantially dried. For example, shortening can be achieved by creping the structure 100 from a rigid surface, such as the surface 210 of the drying drum 200 as shown in FIG. This and other forms of creping are known in the art. U.S. Pat. No. 4,919,756 (Sawdai, issued April 24, 1992) describes one suitable method for creping a web. Of course, a fiber structure 100 without crepes (eg, not creped) and / or otherwise shortened is considered to be a fiber structure 100 without crepes but otherwise shortened. Intended to be inside.

  In certain embodiments, it may be preferred that at least a portion of the synthetic fiber 101 is at least partially melted or softened. When synthetic fibers are at least partially melted or softened, they can be co-joined with adjacent fibers, whether short cellulose fibers 102, long cellulose fibers 103, or other synthetic fibers 101. There is. Fiber co-bonding can include mechanical co-bonding and chemical co-bonding. Chemical co-bonding occurs when at least two adjacent fibers are bonded together at the molecular level such that the identity of the individual co-bonded fibers is substantially lost in the co-bonded area. Mechanical co-bonding of fibers occurs when one fiber simply conforms to the shape of adjacent fibers and there is no chemical reaction between the co-bonded fibers. FIG. 12 illustrates one embodiment of mechanical co-bonding, where the fibers 111 are physically taken up by adjacent synthetic fibers 112. The fibers 111 can be synthetic fibers or cellulose fibers. In the example shown in FIG. 12, the synthetic fiber 112 includes a two-component structure including a core 112a and a sheath or shell, 112b, and the melting temperature of the core 112a is greater than the melting temperature of the sheath 112b, and therefore when heated. Only the sheath 112b melts while the core 112a retains its integrity. However, it should be understood that multi-component fibers containing different types of bi-component fibers and / or more than three components can be used in the present invention, as are single-component fibers. is there.

  In certain embodiments, it may be desirable to redistribute at least a portion of the synthetic fibers 101 within the web 100 after the web 100 is formed. Such redistribution can occur while the web 100 is positioned on the molding member 50 or at different times and / or locations during the process. For example, the formed web 100 is heated using a heating device 90, a drying surface 210, and / or a drying drum hood (eg, a Yankee drying hood 80, etc.) to provide at least a portion of the synthetic fiber 101. Can be redistributed. Without being bound by theory, it is believed that the synthetic fiber 101 can move under the influence of at least one of two phenomena after being subjected to a sufficiently high temperature. . When the temperature is high enough to melt the synthetic fiber 101, the resulting liquid polymer minimizes its surface area / mass due to surface tension and is less sensitive to heat at the end of the fiber portion Tends to form a sphere-like shape. On the other hand, if the temperature is lower than the melting point, the fiber with high residual stress softens to the point where the stress is relaxed by fiber shrinkage or coiling. This is believed to occur because polymer molecules typically prefer to be in a non-linear coiled state. Fibers that have been highly drawn and then cooled during their manufacture consist of polymer molecules drawn into a metastable shape. Subsequent heating returns the fiber to a coiled state with minimal free energy.

  Redistribution may be accomplished with any number of steps. For example, the synthetic fiber 101 is blown with hot gas, for example, through a pillow portion of the web 100 while the fiber web 100 is disposed on the molding member 50, so that the synthetic fiber 101 is redistributed according to the first pattern. By doing so, the first redistribution can be received. The web 100 can then be transferred to another molding member 50 and the synthetic fibers 101 can be further redistributed according to a second pattern.

  Heating the synthetic fibers 101 in the web 100 can be accomplished by heating a plurality of micro regions corresponding to the fluid permeable areas 154 of the molded member 50. For example, hot gas from the heating device 90 can be forced through the web 100. A pre-dryer can also be used as a heat energy source. In either case, depending on the process, the direction of the hot gas flow can be reversed with respect to the direction shown in FIG. 1 so that the hot gas penetrates the web through the molding member 50. The pillow portion 150 of the web that is disposed in the fluid permeable area 154 of the molding member 50 is then primarily affected by the hot gas. The remaining part of the web 100 is shielded from the hot gas by the molding member 50. As a result, the synthetic fiber 101 is predominantly softened or melted at the pillow portion 150 of the web 10. Further, this region is a place where fiber co-joining due to melting or softening of the synthetic fiber 101 is most likely to occur.

  Although the redistribution of the synthetic fibers 101 has been described above as being affected by the passage of hot gas over at least some of the fibers 101, any suitable means for heating the fibers 101 can be used. Can be implemented. For example, thermal fluids and any of microwaves, radio waves, ultrasonic energy, laser or other light energy, heating belts or rolls, heat pins, magnetic energy, or any other known means for heating Combinations may be used. Furthermore, although the redistribution of synthetic fibers 101 is generally referred to as being affected by heating the fibers 101, the redistribution may also occur as a result of cooling a portion of the web 10. . As with heating, the cooling of the synthetic fiber 101 can cause its own redirection with respect to the shape change of the fiber 101 and / or the rest of the web. Furthermore, the synthetic fibers may be redistributed due to reaction with the redistribution material. For example, the synthetic fiber 101 may be subject to a chemical composition that softens or otherwise manipulates the synthetic fiber 101 to affect any shape, orientation, or position within the web 10. Good. Furthermore, the redistribution can be influenced by mechanical means and / or other means such as magnetic, electrostatic etc. Therefore, redistribution of synthetic fibers 101 as described herein should not be considered limited to thermal redistribution of synthetic fibers 101, but rather any portion of synthetic fibers 101 within web 10. Should be considered to encompass all known means for redistributing (eg, changing shape, orientation, or position).

  Although the synthetic fiber 101 may be redistributed by the methods and means described herein, the process of producing a web may include the distribution of long cellulose fibers 103 and / or short cellulose fibers 102 redistributing synthetic fibers 101. Can be selected so as not to be significantly affected by the means used to do so. Thus, the resulting fiber structure 100 has a plurality of long cellulose fibers 103 randomly distributed throughout the fiber structure, whether or not redistributed, and a plurality of composites distributed in a non-random pattern. Fiber 101 can be included. FIG. 10 illustrates one embodiment of a fibrous structure 100 in which long cellulose fibers 103 are randomly distributed throughout the structure and a mixture 104 of synthetic fibers 101 and short cellulose fibers 102 is a non-random repeating pattern. It is distributed with.

  The web creation method of the present invention may also include any other desired steps. For example, the method can include winding a web onto a roll, calendering the web, embossing the web, perforating the web, printing on the web, and / or making the web one or more other webs or materials. And a converting process such as forming a multi-ply structure. Some representative patents describing embossing include US Pat. Nos. 3,414,459, 3,556,907, 5,294,475, and 6,030,690. It is. In addition, the method may include one or more steps that add to or enhance the properties of the web, such as adding softening, strengthening, and / or other treatments to the surface of the product or during web formation. Further, the web may comprise a latex or the like as described, for example, in US Pat. No. 3,879,257 or others.

  Various products can be made using the fiber structure 100 of the present invention. For example, the resulting products include air, oil and water filters; vacuum cleaner filters; furnace filters; face masks; coffee filters, tea or coffee bags; insulation and sound insulation; diapers, women's pads and incontinence Non-woven fabrics for single-use hygiene products such as articles; textile fabrics for water absorption and wear flexibility such as microfibers or breathable fabrics; electrostatically charged structures for dust collection and removal Web; stiffeners and wrapping paper, writing paper, newsprint, hard paper web such as cardboard, and paper tissue grade webs such as toilet paper, paper towels, napkins and facial tissues; surgical curtains, wounds It may find use in medical applications such as bandages, bandages and skin patches. The fiber structure 100 may also include odor absorbents, termite repellents, insecticides, rodenticides, etc. for specific applications. The resulting product can absorb water and oil and find use in oil or water spill cleaning, or controlled water retention and release for agricultural or horticultural applications.

(Non-limiting examples)
Example 1
A pilot-scale long paper machine is used in this example. A 3 wt% aqueous slurry of NSK is made in a conventional repulper. The NSK slurry is lightly refined to produce a 2% solution of a permanent wet strength resin (ie Kymene 557LX marketed by Hercules incorporated, Wilmington, Del.). , Added to the NSK stock tube at a rate of 1% by weight of the dry fiber. Adsorption of Kymene 557LX to NSK is enhanced by an in-line mixer. A 1% solution of carboxymethylcellulose (CMC) is added after the in-line mixer at a rate of 0.2% by weight of the dry fiber to increase the dry strength of the fiber substrate. A 3% by weight aqueous slurry of eucalyptus fibers is made in a conventional repulper.

The NSK furnish and eucalyptus fibers are layered in the headbox and deposited on the long web as different layers to form the initial web. Dehydration occurs through the long web and is assisted by deflectors and vacuum boxes. The long mesh is a 5 shed satin weave construction with 33 monofilaments per centimeter in the machine direction and 30 in the cross machine direction (84 and 77 per inch), respectively. The initial wet web is transferred to the photosensitive polymer fabric fiber consistency of about 22% at the transfer point from the Fourdrinier, photopolymer fabric, 6.45 cm ² Linear Idaho (square inch) per 0.99 (Linear Idaho) Cell, 20% knuckle area, and photosensitive polymer depth of 0.432 mm (17 mils). Further dewatering is achieved by drainage with the aid of vacuum until the web is at a fiber concentration of about 28%. The patterned web is pre-dried by ventilation to a fiber concentration of about 65% by weight. The web is then bonded to the surface of the Yankee dryer with a sprayed creping adhesive containing a 0.25% aqueous solution of polyvinyl alcohol (PVA). The fiber concentration is increased to an estimated 96% by dry creping the web with a doctor blade. The doctor blade has a bevel angle of about 25 degrees and is arranged with respect to a Yankee dryer to form an impact angle of about 81 degrees, the Yankee dryer being about 183 meters per minute (about 600 fpm (feet per minute)) Driven. The dry web is formed into rolls at a speed of 171 m (560 fpm) per minute.

A two-ply web is formed into a paper towel product by being laminated and embossed together using PVA adhesive. The paper towel has a basis weight of about 40 g / m ² and contains a composition of 70% by weight northern softwood craft and 30% by weight eucalyptus. The resulting paper towel has a wet burst after aging of about 374 grams.

(Example 2)
A paper towel is made by a method similar to Example 1, but replacing 10% by weight of Eucalyptus with 10% by weight of 3 mm synthetic two-component polyester fiber. The synthetic / eucalyptus mixture has a fiber length ratio of 4.2, a PTP factor of 1.2, and a fiber roughness value of 11.0 mg / 100 m. Fiber length ratio, PTP coefficient, and fiber roughness values are determined by the Kajaani method shown in the Test Methods section below. The paper towel has a basis weight of about 40 g / m ² and consists of 70% by weight Northern conifer craft in one layer, 20% by weight eucalyptus and 10% by weight 3 mm length synthetic fiber in the other layer. A mixture. The resulting paper towel has a wet burst after aging of about 484 grams.

(Example 3)
A paper towel is made by a method similar to Example 1, but replacing 5% by weight of Eucalyptus with 5% by weight of 6 mm synthetic two-component polyester fiber. The synthetic / eucalyptus mixture was measured as shown in the Test Methods section below and as described in Example 2, with a fiber length ratio of 8.4, a PTP factor of 1.2, and a fiber roughness value of 11. 6 mg / 100 m. The paper towel has a basis weight of about 40 g / m ² and is composed of 70% by weight Northern conifer craft in one layer, 25% by weight eucalyptus and 5% by weight 6 mm synthetic fiber in the other layer. A mixture. The resulting paper towel has a wet burst after aging of about 472 grams.

(Test method)
(Kajaani method)
The length weighted average fiber length of the cellulose fibers and the fiber roughness of the cellulose / synthetic fiber mixture are determined with a Kajaani FiberLab fiber analyzer. The analyzer sets the reporting range from 0 mm to 7.6 mm, sets the profile so that fibers with a length less than 0.08 mm are excluded from the fiber length and fiber roughness calculations, and as per manufacturer recommendations Operated. Particles of this size are excluded from the calculation because they are primarily composed of non-fibrous fragments and are not considered functional for the application to which the present invention is directed.

  Care must be taken in sample preparation to ensure that the correct sample weight is entered into the Kajaani FiberLab instrument. An acceptable method of sample preparation has the following steps.

  1) Determine the moisture content of the sample and then weigh the sample for analysis. The target sample weight for short hardwood fibers is 0.02-0.04 grams and for normal length softwood fibers is 0.15-0.30 grams. The sample must be weighed with an accuracy of +/− 0.1 milligrams for fiber roughness analysis.

  2) Fill the manual disaggregator with about 150 ml of warm water, add the dry sample, and move the agitator of the disaggregator up and down until the sample is completely disaggregated, that is, no fiber bundles or bundles remain in the sample. To disaggregate the dried sample. However, exceeding the required disaggregation time and excessively rough handling of the fiber should be avoided in order not to break the fiber.

  3) The pulp slurry in the manual disaggregator is transferred to a 2000 ml volumetric flask and filled with tap water up to the 2000 ml line. Mix well to achieve uniformity. The dilution accuracy for the fiber roughness sample should be +/- 4 ml.

  4) Determine the concentration of the sample and calculate the amount of sample required using the following formula: Sample amount = (Target concentration × 2000) / (Process concentration), where the target concentration for hardwood is 0. 005 to 0.010%, and 0.015 to 0.025% for conifers.

  5) Add the sample amount to a 2000 ml volumetric flask, fill with tap water up to 2000 ml line and mix well.

  6) Take a 50 ml aliquot of the sample slurry using a pipette with a tip opening of at least 2 mm and place the aliquot into the Kajaani sample container.

7) For fiber roughness analysis, calculate the total sample weight present in a 50 ml aliquot using the following formula: fiber weight in 50 ml aliquot (mg / 50 ml) = (50 ml / 2000 ml) × (weighed) Fiber dry weight, mg)
8) Place the sample container in the Kajaani sample unit and start the analysis.

  9) The Kajaani FiberLab facility automatically reports length-weighted average fiber length in millimeters, average cellulose fiber width in micrometers, and fiber roughness in milligrams / meter. The Kajaani FiberLab facility reports roughness in units of milligrams per meter of unweighted fiber length (mg / m). This value is multiplied by 100 to get the fiber roughness in units of milligrams per 100 meters, as shown in the fiber roughness definition above. Pulp fiber roughness is the average of three fiber roughness measurements of three fiber samples taken from the mixture.

(Wet burst after aging)
Wet burst is a swing Albert burst tester with a 2000 gram load cell, obtained from Thwing-Albert Instrument Co., Philadelphia, Pa. 19154, Philadelphia, Pa. Determined using catalog number 177. The sample is placed in a conditioned room at a temperature of about 22.8 ± 1.1 ° C. (73 ° +/− 2 ° F.) and about 50% + / − 2% relative humidity for at least about 24 hours. The paper is aged in a 105 ° C. oven for about 5 minutes. Using a paper cutter, cut 8 test strips approximately 4.5 inches wide (CD) x 30 inches long (MD) (MD). Wet each strip with distilled water and place the wire face up on the lower ring of the sample holder so that the sample completely covers the opening in the lower ring and a small amount of sample is lowered. Extend beyond the outer diameter of the side ring. After the sample strip is properly placed on the lower ring, the upper ring is lowered with the pneumatic retainer to hold the sample between the upper and lower rings. The diameter of the lower ring opening is about 3.5 inches. The plunger has a diameter of about 0.6 inches. When the tester is activated, the plunger is raised at a rate of about 12.7 cm / min (5 inches per minute) to burst the paper. The tester provides a wet burst strength value in grams directly when the sample bursts. The test results obtained for the eight sample strips are averaged and the wet burst value of the paper sample is recorded in grams.

1 is a schematic side view of an embodiment of a process of the present invention. FIG. 3 is a schematic plan view of an embodiment of a forming member having a substantially continuous framework. Sectional drawing which displays a typical formation member. FIG. 3 is a schematic plan view of an embodiment of a forming member having a substantially semi-continuous framework. The schematic top view of embodiment of the formation member which has the framework of a separability pattern. Sectional drawing which displays a typical formation member. FIG. 3 is a schematic cross-sectional view showing representative synthetic fibers distributed into grooves formed in a forming member. It is sectional drawing which shows the single fiber structure of this invention, and the cellulose fiber is distributed at random on the formation member containing a synthetic fiber. It is sectional drawing of the single fiber structure of this invention, and the cellulose fiber is distributed substantially randomly, and the synthetic fiber is distributed substantially non-randomly. It is sectional drawing of the single fiber structure of this invention, and the synthetic fiber is distributed substantially randomly, and the cellulose fiber is distributed substantially non-randomly. The schematic top view of embodiment of the integral fiber structure of this invention. 1 is a schematic cross-sectional view of a monolithic fiber structure of the present invention between a compression surface and a molded member. FIG. 3 is a schematic cross-sectional view of a two-component synthetic fiber co-joined with another fiber. 1 is a schematic plan view of an embodiment of a molded member having a substantially continuous pattern framework. FIG. FIG. 14 is a schematic cross-sectional view taken along line 14-14 in FIG. 13. It is sectional drawing of a monolithic fiber structure, and a synthetic fiber and a short cellulose fiber are arrange | positioned in one layer, and a long cellulose fiber is arrange | positioned in the adjacent layer.

Claims (20)

  A fibrous structure comprising at least two layers, wherein at least one of the layers of the fibrous structure comprises long cellulose fibers and at least one of the layers comprises a mixture of short cellulose fibers and synthetic fibers. Preferably, at least a part of the synthetic fiber is bonded to at least a part of the short cellulose fiber.   The fiber structure according to claim 1, wherein the mixture of short cellulose fibers and synthetic fibers has a fiber length ratio of more than 1, preferably a fiber length ratio between 1 and 20.   The fiber structure according to any one of claims 1 and 2, wherein the mixture of short cellulose fibers and synthetic fibers has a PTP coefficient exceeding 0.75.   The short cellulose fibers have a length weighted average fiber length of less than 2 mm, preferably the short cellulose fibers have a length weighted average fiber length of less than 1 mm and an average cellulose fiber width of less than 18 micrometers; The fiber structure according to any one of claims 1 to 3.   The fiber structure according to any one of claims 1 to 4, wherein the synthetic fiber has a length-weighted average fiber length exceeding 2 mm and an average synthetic fiber diameter exceeding 15 micrometers.   The fiber structure according to any one of claims 1 to 5, wherein the long cellulose fibers have a length weighted average fiber length of more than 2 mm and an average cellulose fiber width of less than 50 micrometers.   The fiber structure according to any one of claims 1 to 6, wherein the mixture of short cellulose fibers and synthetic fibers has a fiber roughness value of less than 50 mg / 100 m, preferably less than 25 mg / 100 m. .   The fiber structure according to any one of claims 1 to 7, wherein the monolithic fiber structure is creped, not creped, or embossed.   9. The fiber structure of any one of claims 1-8, wherein the fiber structure is combined with a separate fiber structure to form a multi-ply article.   The fiber structure according to any one of claims 1 to 9, comprising a latex disposed on at least a part of the monolithic fiber structure. Feeding the mixture of synthetic fibers and short cellulose fibers onto a forming member so as to form one or more layers comprising a mixture of synthetic fibers and short cellulose fibers; Having a pattern, and at least a portion of the synthetic fiber is disposed in the groove,
Providing a plurality of long cellulose fibers on the mixture of synthetic fibers and short cellulose fibers so as to form one or more layers predominantly comprising long cellulose fibers;
Forming a monolithic fiber structure comprising the one or more layers comprising a mixture of the synthetic fibers and short cellulose fibers and one or more layers predominantly comprising long cellulose fibers. Manufacturing method. Providing a first aqueous slurry comprising a mixture of synthetic fibers and short cellulose fibers;
Preparing a second aqueous slurry containing a plurality of long cellulose fibers;
Depositing the first and second aqueous slurries on a fluid permeable forming member having a groove pattern;
Partially dewatering the deposited first and second aqueous slurries to form a fibrous web; and the plurality of fibrous webs randomly distributed throughout at least one layer of the fibrous web A mixture of said synthetic fibers and short cellulose fibers at least partially non-randomly distributed in the grooves,
Forming the fiber web by the groove pattern by applying fluid differential pressure to the fiber web disposed on the molding member, and the fiber web disposed on the molding member is formed by the molding A first plurality of micro-regions corresponding to a plurality of fluid-permeable regions of the member; and a second plurality of micro-regions corresponding to the plurality of fluid-impermeable regions of the molded member;
Transferring the fibrous web from the molded member to a dry surface;
The mixture of synthetic fibers and short cellulose fibers is arranged in a predetermined pattern, and the plurality of long cellulose fibers remain distributed generally randomly throughout at least one layer of the fibrous structure. Forming a monolithic fiber structure; and a method for producing the monolithic fiber structure.   The mixture of synthetic fibers and short cellulose fibers has a fiber length ratio of more than 1, preferably the mixture of synthetic fibers and short cellulose fibers has a fiber length ratio between 1 and 20. The manufacturing method of any one of 11 and 12.   The method according to any one of claims 11 to 13, wherein the mixture of synthetic fibers and short cellulose fibers has a fiber roughness value of less than 50 mg / 100 m.   The method according to any one of claims 11 to 14, further comprising a step of redistributing at least a part of the synthetic fiber by heating or cooling at least a part of the part of the synthetic fiber. .   The manufacturing method of any one of Claims 11-15 including the process of embossing the said fiber structure between a formation member and a dry surface, and densifying a part of said fiber structure. The forming member is moving at a first speed, and the manufacturing method includes:
Preparing a second member having a second speed that is slower than the first speed;
The manufacturing method according to claim 11, further comprising: transferring the initial web from the forming member to the second member and causing the initial web to be finely contracted.   The manufacturing method according to claim 11, wherein the monolithic fiber structure is creped, not creped, or embossed.   The manufacturing method of any one of Claims 11-18 including the process of supplying latex to at least one part of the at least 1 surface of the said integral fiber structure. The manufacturing method according to any one of claims 11 to 19, wherein a mixture of the synthetic fiber and the short cellulose fiber is supplied onto the forming member before the plurality of long cellulose fibers are supplied.

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