JP2013241718A - Multilayered fiber structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayered fiber structure that includes a web layer containing a cellulose fiber, maintains flexibility and water-absorbing properties of the web, has superior extensibility, and has layers that are appropriately integrated.SOLUTION: The multilayered fiber structure includes the web layer that contains 20 mass% or more of the cellulose fiber and has an apparent density of 0.065-0.170 g/cmand a knitted fabric layer that has a course density of 35-73/2.54 cm, a wale density of 30-64/2.54 cm and a basis weight of 10-120 g/m, has the web layer and the knitted fabric layer which are integrated by water flow interlacing treatment, and has an elongation in a width direction of 50-200%.

Description

  The present invention relates to a multilayer fiber structure having a web layer containing cellulose fibers and a knitted fabric layer and having excellent extensibility.

  In general, non-woven fabrics containing cellulose fibers are soft to the touch and have high water absorption, so it is recommended to use hygienic surface materials, wet tissues, disposable towels, masks, medical gowns, wiping cloths, cosmetic sheets and cosmetics. It is used in various products such as impregnated cosmetic face masks. In these products, it is preferable that the non-woven fabric has an appropriate extensibility from the viewpoint of enhancing the feeling of use.

  As a nonwoven fabric having extensibility, for example, a stretchable nonwoven fabric (Patent Document 1) in which a web layer made of predetermined fibers and a reinforcing material containing polyurethane fibers are integrated by hydroentanglement, and has high stretchability in at least one direction A non-woven fabric having a multilayer structure such as a composite elastic sheet (Patent Document 2) in which a non-woven fiber web is integrated on one side or both sides of a net-like structure with a streak has been proposed. However, in these nonwoven fabrics, the extensibility may be insufficient, or the integration between layers may be insufficient.

JP 2004-149933 A JP-A-10-195746

  An object of the present invention is a multilayered fiber structure including a cellulose fiber-containing web layer, which is excellent in extensibility while maintaining the properties (flexibility, water absorption, etc.) of the web, and the layers are separated from each other. It is to provide a multilayer fiber structure which is appropriately integrated.

According to the present invention, a multilayer fiber structure is provided. The multilayer fiber structure includes 20% by mass or more of cellulose fibers, an apparent density of 0.065 to 0.170 g / cm ³ , a course density of 35 to 73 / 2.54 cm, and a wale density Is a knitted fabric layer having a basis weight of 10 to 120 g / m ² , the web layer and the knitted fabric layer are integrated by hydroentanglement treatment, The elongation is 50 to 200%.
In preferable embodiment, the delamination force of the said web layer and the said knitted fabric layer is 0.5-10.0N.
In a preferred embodiment, the web layer comprises a cotton web having a brightness index (Rd) of 90 to 100% and a yellowness index (+ b) of −2.0 to 1.0.
In a preferred embodiment, the average fiber length of the constituent fibers of the web layer is 13 to 51 mm.
In a preferred embodiment, the knitted fabric layer includes heat-fusible elastic fibers.
In a preferred embodiment, the multilayer fiber structure is a two-layer fiber structure.
In a preferred embodiment, the multilayer fiber structure is a three-layer fiber structure in which the web layer is disposed on both sides of the knitted fabric layer.
In a preferred embodiment, the multilayer fiber structure is a three-layer fiber structure in which the knitted fabric layer is disposed on both sides of the web layer.
According to another aspect of the present invention, a textile product is provided. The fiber product includes the multilayer fiber structure.
According to a preferred embodiment, the textile product is a face mask.

  According to the present invention, by using a cellulose fiber-containing web layer having a predetermined apparent density and a knitted fabric layer having a predetermined knitting density and a basis weight, it is excellent in extensibility while maintaining the properties of the web, and A multilayer fiber structure in which the layers are appropriately integrated can be provided.

1 is a schematic cross-sectional view of a multilayer fiber structure according to a preferred embodiment of the present invention.

A. Multilayer fiber structure A-1. Overall Configuration of Multilayer Fiber Structure FIGS. 1 (a) to 1 (c) are schematic cross-sectional views of a multilayer fiber structure according to a preferred embodiment of the present invention. The multilayer fiber structure of the present invention includes 20% by mass or more of cellulose fibers, an apparent density of 0.065 to 0.170 g / cm ³ , a course density of 35 to 73 / 2.54 cm, A knitted fabric layer having a wale density of 30 to 64 / 2.54 cm and a basis weight of 10 to 120 g / m ² . A multilayer fiber structure 100 a in FIG. 1A is a two-layer fiber structure including a web layer 10 and a knitted fabric layer 11. A multilayer fiber structure 100b in FIG. 1B is a three-layer fiber structure in which the web layer 10a is disposed on one surface of the knitted fabric layer 11 and the web layer 10b is disposed on the other surface. A multilayer fiber structure 100c in FIG. 1C is a three-layer fiber structure in which a knitted fabric layer 11a is disposed on one surface of the web layer 10 and a knitted fabric layer 11b is disposed on the other surface. In the multilayer fiber structures 100a to 100c, the constituent fibers of the web layer 10 and the knitting yarn of the knitted fabric layer 11 are entangled by the hydroentanglement process, whereby the web layer 10 and the knitted fabric layer 11 are joined and integrated. It has become. In the multilayer fiber structure 100b, the constituent fibers of the web layer 10a and the constituent fibers of 10b may be entangled through the knitted fabric layer 11. Although not shown, the multilayer fiber structure of the present invention may be a multilayer fiber structure having four or more layers in which web layers and knitted fabric layers are alternately laminated.

  In the present invention, by selecting a knitted fabric layer having the predetermined knitting density and the basis weight, and adjusting the apparent density of the web layer to a predetermined range, the constituent fibers of the web layer and the knitting yarn of the knitted fabric Can be suitably performed. As a result, the web layer and the knitted fabric layer are integrated with an appropriate bonding force while maintaining the properties derived from the web (flexibility, water absorption, etc.) and the properties derived from the knitted fabric (extensibility, fit, etc.). Multi-layer fiber structures can be obtained.

  The elongation in the width direction (CD direction) of the multilayer fiber structure of the present invention is 50 to 200%, preferably 55 to 200%, more preferably 55 to 190%. If the elongation is less than 50%, the elongation may be insufficient and feel hard. On the other hand, if the elongation exceeds 200%, the layers may be separated during use. Here, the width direction of the multilayer fiber structure means a direction orthogonal to the machine direction (conveying direction) of the web and the knitted fabric when the multilayer fiber structure is produced. Normally, the direction in which the elongation is the largest on the main surface of the multilayer fiber structure can be determined as the width direction. Since the multilayer fiber structure of the present invention is typically produced by subjecting a web and knitted fabric that are continuously conveyed to hydroentanglement using a nozzle, the machine direction (conveying direction) in the width direction. This is because the water flow becomes discontinuous and the binding strength of the fibers becomes weaker.

  The elongation in the flow direction (MD direction) of the multilayer fiber structure of the present invention is preferably 10 to 160%, more preferably 14 to 160%, and still more preferably 18 to 150%. If the elongation is less than 10%, the elongation may be insufficient and feel hard. If the elongation exceeds 160%, the layers may be separated during use. For example, when the knitted fabric layer does not contain heat-fusible elastic fibers (details will be described later in section A-3), the elongation in the flow direction of the multilayer fiber structure is preferably 10 to 60%, more preferably Is from 14 to 50%, more preferably from 18 to 40%. Further, for example, the elongation in the flow direction of the multilayer fiber structure when the knitted fabric layer includes heat-fusible elastic fibers is preferably 20 to 160%, more preferably 28 to 160%, and still more preferably. Is 41 to 150%. Here, the flow direction of the multilayer fiber structure means a direction parallel to the machine direction (conveying direction) of the web and the knitted fabric when the multilayer fiber structure is produced. In general, the direction in which the elongation is smallest on the main surface of the multilayer fiber structure can be determined as the flow direction.

  The delamination force between the web layer and the knitted fabric layer in the multilayer fiber structure of the present invention is preferably 0.5 to 10.0 N, more preferably 0.5 to 9.0 N, and still more preferably 0.5 to 8. 0N. If the delamination force is within such a range, the web layer and the knitted fabric layer do not easily peel off during use, and the web features such as flexibility, water absorption, water retention, and knitted fabric features. It is possible to achieve both the extensibility, the fit and the like. On the other hand, when the delamination force is less than 0.5 N, the elongation of the multilayer fiber structure and the flexibility of the web can be good, but the bonding between the web layer and the knitted fabric layer is insufficient, May separate. Also, if the delamination force is greater than 10.0 N, there is virtually no possibility of layer separation during use, but the constituent fibers of the web layer are entangled and integrated with the knitting yarn of the knitted fabric more than necessary. As a result, problems such as loss of flexibility of the web, insufficient elongation of the multilayer fiber structure, and weak entanglement among the constituent fibers of the web layer may occur.

  In the multilayer fiber structure of the present invention, the web layer and the knitted fabric layer are preferably joined to each other at the contact surfaces of both layers. Specifically, it is preferable that the constituent fibers of the web layer are entangled and joined to the exposed portion of the knitting yarn of the knitted fabric on the knitted fabric surface. More specifically, it is preferable that almost no constituent fiber of the web layer is present in a void portion of the knitted fabric (a portion where no knitting yarn exists, for example, a gap inside the loop in the case of horizontal knitting). In one embodiment, the amount of the constituent fibers present in the void portion (the mixing rate of the constituent fibers of the web layer in the knitted fabric layer) may be 10% by mass or less of the entire constituent fibers of the web layer. In this way, the web layer and the knitted fabric layer are bonded at the contact surfaces of both layers, whereby an appropriate bonding force (delamination force) is obtained. As a result, both layers do not easily peel off during use. In addition, the flexibility, water absorption, water retention, etc., which are the characteristics of the web, and the extensibility, fit, etc., which are the characteristics of the knitted fabric, can be achieved.

  The elongation recovery rate in the width direction of the multilayer fiber structure of the present invention is preferably 15% or more, more preferably 20% or more, and further preferably 25% or more. When the elongation recovery rate is less than 15%, for example, when used as a face mask, the fit to the skin is insufficient and there is a risk of peeling. The preferred upper limit depends on the intended use and location, but for example, when used for apparel such as gowns, jackets, trousers and underwear, and for medical hygiene such as sanitary products and diapers, the upper limit of elongation recovery rate is 100%. It can be.

  The initial elongation force (5% load) in the flow direction of the multilayer fiber structure of the present invention is preferably 0.1 to 100N, more preferably 0.2 to 80N, and still more preferably 0.3 to 60N. It is. When the initial elongation force is less than 0.1 N, the initial elongation is good, but the web may break or the layers may be separated during the elongation. On the other hand, when the initial elongation force exceeds 100 N, it is hard and difficult to stretch, and may not be suitable for use. For example, the initial elongation force (5% load) in the flow direction of the multilayer fiber structure when the knitted fabric layer does not include heat-fusible elastic fibers is preferably 5 to 100 N, more preferably 7 to 80 N. More preferably, it is 9-60N. In addition, for example, the initial elongation force (5% load) in the flow direction of the multilayer fiber structure when the knitted fabric layer includes heat-fusible elastic fibers is preferably 0.1 to 20 N, more preferably 0.00. It is 2-15N, More preferably, it is 0.3-8.9N.

  The curl degree of the multilayer fiber structure of the present invention is preferably 0 to 40%, more preferably 0 to 10% in both the flow direction and the width direction. When the curl degree exceeds 40%, the cut portion is curled, and there are cases where, for example, when used as a face mask, problems such as a decrease in adhesion and easy peeling from the face may occur. In the present invention, the curl means that the end face of the multilayer fiber structure is turned up, and may be caused by, for example, the residual torque of the knitting yarn of the knitted fabric layer.

  The bending resistance of the multilayer fiber structure of the present invention is preferably 20 to 200 mm, more preferably 20 to 180 mm, for example 20 to 150 mm, for example 20 to 140 mm, in the flow direction. On the other hand, the bending resistance is preferably 10 to 200 mm, more preferably 10 to 180 mm in the width direction, for example, 10 to 140 mm, and for example, 10 to 130 mm. When the bending resistance is less than the above range, sufficient flexibility can be obtained, while problems such as fluffing, web dropping off, and poor shape retention in the thickness direction occur in a two-layer fiber structure. There is. On the other hand, when it exceeds the above range, it tends to be hard. For example, when it is used for a face mask, problems such as easy peeling may occur.

In the case of a two-layer fiber structure, the basis weight of the multilayer fiber structure of the present invention is preferably 20 to 320 g / m ² , more preferably 20 to 20 from the viewpoints of water absorption, flexibility, extensibility, lightness, and the like. It was 260 g / ^{m 2,} when the three-layered fiber structure web layer is disposed on both sides of the knitting formation is preferably 30~520g / ^{m 2,} more preferably a 30~410g / ^{m 2,} the web layer In the case of a three-layer fiber structure in which a knitted fabric layer is disposed on both sides, it is preferably 30 to 440 g / m ² , more preferably 30 to 370 g / m ² .

  The total thickness of the multilayer fiber structure of the present invention can be appropriately set depending on the application and the like. For example, in the case of a two-layer fiber structure, the thickness is preferably 0.10 to 4.90 mm, more preferably 0.10 to 4.00 mm, and in the case of a three-layer fiber structure, the thickness is preferably 0.00. It is 15 to 7.80 mm, more preferably 0.15 to 6.10 mm.

A-2. Web layer A web layer is comprised from the web containing 20 mass% or more of cellulose fibers. The cellulose fiber content in the web is preferably 50% by mass or more, more preferably 70% by mass or more, and may be 100% by mass. When the content of the cellulose fiber is less than 20% by mass, problems such as deterioration of the touch and reduction of water absorption may occur. For example, when used for a cosmetic face mask, Problems such as a decrease in moisture retention may occur.

  Examples of the cellulose fiber include plant and animal natural cellulose fibers such as cotton, hemp, bamboo, ridge, honey, banana, kapok, and saccharid, rayon fibers (for example, rayon, cupra, polynosic, tencel). ) And semi-synthetic cellulose fibers such as acetate fibers (for example, bisacetate and triacetate). Of these, cotton, rayon, cupra, polynosic, tencel, and acetate are preferable, and cotton is more preferable. By using these fibers, fluffing can be reduced and soft feeling can be enhanced. Furthermore, since cotton is a natural fiber, it has the advantage of being environmentally friendly. In one embodiment, the web may contain 100% cotton by weight. A cellulose fiber may use only 1 type and may use it in combination of 2 or more type.

  As the other constituent fiber that can be used in combination with the cellulose fiber in the web, any appropriate fiber can be selected depending on the use and the like. Examples thereof include chemically synthesized fibers such as polyester fibers, polyamide fibers, polyurethane fibers, polyolefin fibers (for example, polyethylene fibers and polypropylene fibers), polyimide fibers, and polylactic acid fibers.

  In the web layer, typically, the constituent fibers of the web exist in an entangled state.

  The average fiber length of the constituent fibers of the web is preferably 13 to 51 mm, more preferably 21 to 41 mm. When the average fiber length is less than 13 mm, the entanglement between the fibers in the web layer becomes weak and the strength of the web layer becomes insufficient, or the bonding force between the web layer and the knitted fabric layer, that is, the delamination force And the multilayer fiber structure may become hard. On the other hand, when the average fiber length exceeds 51 mm, a sufficiently strong web layer can be obtained, while the delamination force between the web layer and the knitted fabric layer is lowered, which may cause a problem in durability of the multilayer fiber structure. .

  The average diameter of the constituent fibers of the web is preferably larger than 10 μm, more preferably more than 10 μm and 20 μm or less. When the average diameter is 10 μm or less, the entanglement between the fibers in the web layer becomes strong and the web becomes hard, or the delamination force between the web layer and the knitted fabric layer becomes high, and the multilayer fiber structure becomes hard. There is a case. On the other hand, when the average diameter is larger than 20 μm, the entanglement between the fibers in the web layer becomes weak and the strength of the web layer becomes insufficient, or the delamination force with the knitted fabric layer decreases, May break or peel. The average fiber length and average diameter of the constituent fibers of the web can be determined as follows. For cotton fibers, using an HVI measuring instrument (High Volume Instrument, USTER, Type Spectrum), using 4 g of web as a sample at one time, the average value after five measurements was taken as the average fiber length and micronar fineness. The average diameter is calculated using the micronaire fineness and the specific gravity of the web constituent fibers. For other than cotton fibers, for example, the fiber length and diameter of 100 or more fibers can be measured by microscopic observation, and the average value can be calculated. In the case of a synthetic fiber cut at a constant length, it may be calculated as an average value of 10 or more.

  It is preferable that impurities are removed from the surface of the constituent fibers of the web. This is because the entanglement between the fibers during hydroentanglement is made uniform and can be entangled efficiently. Moreover, water absorption can also be improved. The reason why such an effect is achieved is not clear, but by removing impurities on the fiber surface, the fiber is easily loosened and the surface area is increased, thereby exposing more hydroxyl groups of cellulose on the fiber surface. It is presumed that. Examples of the treatment for removing impurities from the surface include bleaching treatment and bleaching treatment. The bleaching treatment and the bleaching treatment can be carried out, for example, using hydrogen peroxide as a drug, and appropriately setting the drug concentration and the processing time.

  Since cotton is bleached and / or bleached to remove impurities and improve whiteness, when the constituent fiber is cotton, whiteness can be used as an index for removing impurities. Specifically, by using a cotton web having a brightness index (Rd) of 90 to 100% and a yellowness index (+ b) of −2.0 to +1.0, the above-described effect is suitably achieved. Can be done. When Rd is less than 90% or the absolute value of + b is more than 1, impurities remain on the fiber surface, resulting in frequent nesting, etc., resulting in a decrease in aesthetics, making entanglement difficult and delamination force Problems such as degradation can occur. When the brightness index (Rd) is 100% and the yellowness index (+ b) is 0, it is evaluated that the whiteness is the highest (white).

The apparent density of the web layer in the multilayer fiber structure of the present invention, a 0.065~0.170g / cm ^3, preferably 0.065~0.165g / cm ^3, more preferably 0.065 ˜0.160 g / cm ³ . If the apparent density is within such a range, the extensibility of the multilayer fiber structure and the delamination force between the web layer and the knitted fabric layer can be adjusted to a desired range, and the flexibility, water absorption, etc. An excellent web layer can be obtained. Here, the apparent density is a value calculated from the mass (weight per unit area) and thickness of the web layer.

Basis weight of the web layers in a multilayer fiber structure of the present invention is preferably 10 to 200 g / ^{m 2,} more preferably from 10 to 150 g / ^{m 2,} more preferably from 10 to 100 g / ^{m 2.} If the weight per unit area is less than 10 g / m ² , a thin web portion may be formed, a web may be partially lost, pinholes may be formed, and a knitted fabric may be exposed, so that a uniform web layer may not be formed. . On the other hand, when the weight per unit area exceeds 200 g / m ² , the multilayer fiber structure becomes heavy. For example, when used for a face mask or the like, the adhesion to the skin may be impaired and the skin may be easily peeled off.

  The thickness of the web layer in the multilayer fiber structure of the present invention can be appropriately set depending on the application and the like. The thickness is, for example, 0.05 to 3.00 mm, preferably 0.06 to 2.30 mm, and more preferably 0.06 to 1.40 mm.

A-3. Knitted fabric layer As the knitted fabric of the knitted fabric constituting the knitted fabric layer, any appropriate knitted fabric can be selected according to the use or the like. It may be warp or weft. Typically, weft knitting is used, and for example, flat knitting (tenji knitting, plain knitting, single jersey), rubber knitting (rib knitting, milling knitting) and the like can be preferably used. The weft knitted fabric may be a single knitted fabric or a double knitted fabric. For example, a double knitted fabric is preferable in terms of suppressing curling of the multilayer fiber structure, and a single knitted fabric is preferable in terms of reducing the thickness or suppressing the manufacturing cost.

  In the present invention, a knitted fabric having a predetermined knitting density is provided for the purpose of imparting excellent flexibility and extensibility to the multilayer fiber structure and obtaining an appropriate bonding force between layers (a delamination force). Selected. Specifically, the knitting density in the weft knitting is a course density of 35 to 73 / 2.54 cm and a wale density of 30 to 64 / 2.54 cm. If the knitting density is lower than the above range, the extensibility of the knitted fabric itself may be improved, but the extensibility of the resulting multilayer fiber structure may be insufficient. This is because water flow easily passes through the knitted fabric during hydroentanglement, and the web's constituent fibers gather around the knitting yarn of the knitted fabric and strongly entangle it, while being arranged on the gap (loop gap) on the knitted fabric surface Since the amount of webs to be reduced is reduced, the entanglement between the constituent fibers of the web at the location is weakened, and the web layer is likely to break due to elongation. Here, by weakening the hydroentanglement force, the amount of the web disposed on the gap on the surface of the knitted fabric can be increased, but the bonding force between the web layer and the knitted fabric layer is reduced, so that the web is in use as a product. Problems such as easy separation of the layer and the knitted fabric layer may occur. In addition, by increasing the hydroentanglement force, it is possible to improve the bonding force between the web layer and the knitted fabric layer, but the amount of web placed on the voids on the surface of the knitted fabric is further reduced, and before use as a product. Problems such as pinholes occurring in part of the web layer may occur. Further, when the knitting density is higher than the above range, the thickness unevenness (thickness unevenness) of the web layer can be reduced, but the extensibility of the multilayer fiber structure and the bonding force between the web layer and the knitted fabric layer are insufficient. There is. This is presumably because the extensibility of the knitted fabric itself decreases and the water flow hardly passes through the knitted fabric during the hydroentanglement, and the entanglement between the constituent fibers of the web and the knitted yarn of the knitted fabric is weakened. For example, when entangled by jetting a water flow from the web layer side toward the knitted fabric layer side, the constituent fibers of the web are strongly entangled by the water flow that bounces back to the web layer without passing through the knitted fabric layer. Entangling with the yarn becomes insufficient, and problems such as separation of the web layer and the knitted fabric layer may occur during use as a product. Here, it is possible to improve the bonding force between the web layer and the knitted fabric layer by increasing the hydroentanglement force, but the entanglement between the constituent fibers of the web also becomes stronger, so that the extensibility may be insufficient. Further, as a result of the density of the web layer being increased, problems such as feeling hard and a decrease in water absorption may occur. The course density is preferably 35 to 70 / 2.54 cm. The wale density is preferably 30 to 60 / 2.54 cm. With such a knitting density, a multilayer fiber structure excellent in flexibility and extensibility can be suitably obtained while ensuring practically sufficient durability of the web layer and bonding strength between the layers.

Basis weight of the knitted fabric is 10~120g / ^{m 2,} preferably 15~120g / ^{m 2,} more preferably from 10 to 100 g / ^{m 2.} When the weight per unit area is less than 10 g / m ² , the bursting strength and tearing strength may be low, and problems such as the knitted fabric layer breaking during use may occur. On the other hand, when the basis weight exceeds 120 g / m ² , it is difficult to follow the movement of the body if the multilayer fiber structure is used for a fiber product that fits the body due to the effect of the knitted fabric becoming hard or heavy. May feel uncomfortable due to increased weight and stuffiness.

  The elongation in the course direction of the knitted fabric is preferably 120 to 600%, more preferably 150 to 600%, and still more preferably 200 to 550%. If the elongation in the course direction is less than 120%, the knitted fabric may become hard, and if it exceeds 600%, problems such as deformation of the stitch and poor shape retention may occur. On the other hand, the elongation in the wale direction of the knitted fabric is, for example, 10 to 600%, preferably 10 to 550%, and more preferably 10 to 500%. If the elongation in the wale direction is less than 10%, the knitted fabric may be hard, and if it exceeds 600%, problems such as deformation of the stitches and poor shape retention may occur. For example, the elongation in the wale direction of the knitted fabric not including the heat-fusible elastic fiber is, for example, 10 to 200%, preferably 10 to 150%, and more preferably 10 to 100%. Further, for example, the elongation in the wale direction of the knitted fabric including the heat-fusible elastic fiber is, for example, 30 to 600%, preferably 40 to 550%, more preferably 50 to 500%.

  As the knitting yarn of the knitted fabric, any appropriate fiber can be used depending on the use or the like. For example, the same type of fibers as the constituent fibers of the web layer described above can be used. In one embodiment, it is preferable that a knitted fabric contains 20 mass% or more of a cellulose fiber, More preferably, it contains 50 mass% or more, More preferably, it contains 70 mass% or more. By using such a knitted fabric in combination with a web layer containing a predetermined amount or more of cellulose fibers, the content of cellulose fibers can be maximized, and as a result, a multilayer fiber structure having extremely excellent water absorption and texture is obtained. be able to. Moreover, since it becomes easy to entangle with the constituent fibers of the web layer, it can be advantageous from the viewpoint of obtaining a uniform delamination force. Furthermore, since the shape retention can be enhanced by the crosslinking treatment of cellulose using a crosslinking agent, the structure of the multilayer fiber structure can be stabilized. Content of the said cellulose fiber is a value calculated | required based on JISL1030-2.

  The fineness of the knitted yarn of the knitted fabric (knitted yarn other than the heat-fusible elastic fiber described later) is preferably 49 to 147 dtex (40 to 120 in English cotton count). When the fineness exceeds 147 dtex, the texture of the multilayer fiber structure may be hardened or thickened. On the other hand, when it is less than 49 dtex, there may be a problem that the rupture strength and tear strength of the knitted fabric are lowered and the production cost is increased. From the viewpoint of water absorption, flexibility, extensibility, knitted fabric strength, thickness, weight and the like of the multilayer fiber structure, a preferable fineness is 59 to 98 dtex. For example, as a yarn having a fineness of 98 dtex (English cotton count 60), a single yarn of 98 dtex (English cotton count 60), a double yarn consisting of a single yarn of 49 dtex (English cotton count 120), etc. Can be used.

  The knitted fabric may include a heat-fusible elastic fiber as a knitting yarn. By using a knitted fabric in which heat-fusible elastic fibers are heat-sealed by heat treatment or the like, a multilayer fiber structure with little dimensional change and excellent shape retention can be obtained. Further, even when the multilayer fiber structure is cut, the fiber product is less likely to fray from the cut surface of the knitted fabric, so that a highly durable fiber product can be provided. Further, by forming the multilayer fiber structure in a state in which the heat-fusible elastic fiber is not heat-sealed, and then heat-sealing it, the bonding strength between the knitted fabric layer and the web layer can be increased. In the multilayer fiber structure obtained in this way, the flexibility of the web can be maintained, unlike the case where the hydroentanglement is strengthened to increase the bonding force between the layers. Furthermore, as in the case where the multilayer fiber structure is formed after heat fusion, a multilayer fiber structure excellent in shape retention and durability of the cut surface can be obtained. In the present invention, heat fusion refers to heat-fusible elastic fibers and / or heat-fusible elastic fibers and other fibers due to heat or heat and pressure from the outside. Are in a state in which the fibers are fused and in close contact, in a state in which at least a part of the fibers are fused and in close contact, or in a state in which the fibers are bonded to each other even if the fusion does not occur.

  As the heat-fusible elastic fiber, a heat-fusible polyurethane elastic fiber is preferable. It is flexible and stretches like rubber, and when heated it causes deformation due to fusion at the contact points between the fibers or other fibers, but it continues without melting and coming out of the knitted part after fusion. This is because flexibility can be maintained. In contrast, a heat-fusible fiber that melts when melted, escapes from the knitting site, penetrates into other fibers, and solidifies. It is not preferable in terms of strengthening. In addition, knitted fabrics containing heat-sealable polyurethane elastic fibers are less likely to curl at both ends in the course direction, and dimensional changes due to hydroentanglement are small, improving process stability during production and uniformity of multilayer fiber structures Thus, effects such as improvement of curl and curl reduction can be obtained. For example, an excellent curl reduction effect can be obtained by knitting into a single knitted fabric that tends to cause curling, such as a knitted sheet, and heat-sealing.

  The heat-fusible polyurethane elastic fiber can be obtained by any appropriate manufacturing method. As the production method, for example, a polyol and an excess molar amount of diisocyanate are reacted to produce a polyurethane intermediate polymer having isocyanate groups at both ends, and active hydrogen that can easily react with the isocyanate group of the intermediate polymer is produced. A polyurethane solution (polymer solution) is produced by reacting a low molecular weight diamine or low molecular weight diol in an inert organic solvent, and then the solvent is removed to form a yarn, or polyol, diisocyanate, low molecular weight diamine or low A method in which a polymer reacted with a molecular weight diol is solidified and dissolved in a solvent, then the solvent is removed and formed into a yarn, a method in which the solidified polymer is formed into a yarn by heating without dissolving in the solvent, a polyol And a diisocyanate and a low molecular weight diol are reacted to obtain a polymer. Method of forming the yarn without reduction, and further, after mixing the polymer or polymer solution obtained in each of the above methods, and a method of forming into the solvent is removed yarn from the mixed polymer solution. Preferably, a polymer obtained by reacting a both-end isocyanate group prepolymer obtained by reacting a polyol with a diisocyanate and a both-end hydroxyl group prepolymer obtained by reacting a polyol, a diisocyanate and a low molecular weight diol (spinning). This is a method of melt spinning without solidifying the polymer. This is because a heat-fusible polyurethane elastic fiber that can be easily fused at low temperatures and has heat resistance can be obtained. Examples of the polyol, diisocyanate, diamine, and diol that can be used in the production of the heat-fusible polyurethane elastic fiber include those described in JP2011-74516A.

  The heat-fusible elastic fiber may be used alone as it is, or may be used in the form of a composite yarn. When used alone, it may be in any form such as a raw yarn (unprocessed yarn), false twisted yarn, pre-dyed yarn, and original yarn. When used as a composite yarn, a heat-fusible elastic fiber is used as a core yarn, and the surrounding yarn is covered with non-heat-fusible fiber. The heat-fusible elastic fiber and non-heat-fusible fiber are twisted together. It may be in the form of a twisted yarn, an air entangled yarn or the like. The lower the coverage of the heat-fusible elastic fiber, the more heat-sealable locations. Therefore, from the viewpoint of improving the heat-fusibility, it is preferable to use it alone, for example, as raw yarn (unprocessed yarn). On the other hand, from the viewpoint of increasing the strength of the knitted fabric, it is preferably used in the form of a composite yarn. Among the composite yarns, a heat-fusible elastic fiber can be arranged at the center of the composite yarn, and the covering rate of the heat-fusible elastic fiber can be controlled easily and uniformly, so a covering yarn is used. It is preferable that a single covering yarn (SCY) is more preferable. The heat-fusible elastic fiber can be used by being knitted by a known method. For example, the heat-fusible elastic fiber is knitted as a constituent yarn of a flat knitting structure or a rubber knitting structure. It can be used by knitting as a splicing yarn or knitting as an elastic yarn for elastic yarn insertion knitting.

  The fineness of the heat-fusible elastic fiber is set to any appropriate fineness depending on the application. In the case of a heat-fusible polyurethane elastic fiber, it is typically 11 to 622 dtex. When the fineness increases, the knitted fabric approaches a rubber-like feel, and the like is preferably 311 dtex or less, and more preferably 267 dtex or less. If the fineness is less than 11 dtex, the productivity of the fiber may decrease, or the yarn may break due to heat fusion.

  The non-heat-fusible fiber when used in the form of a composite yarn is not particularly limited. For example, natural fibers such as cotton, hemp, wool, and silk, regenerated fibers such as rayon, cupra, and polynosic, acetate, etc. Semi-regenerated fibers, chemically synthetic fibers such as nylon, polyester, acrylic, polypropylene, and vinyl chloride can be used. Among these, nylon or polyester is preferable for long fibers, and fibers containing 50% by mass or more of cotton are preferable for short fibers. This is because these fibers are excellent in ease of production of the composite yarn, texture and the like.

  In the present invention, a heat-fusible conjugate yarn can also be used as the heat-fusible elastic fiber. Any appropriate thermoplastic elastomer or thermoplastic resin can be used as a raw material for the heat-fusible conjugate yarn. Examples of the soft segment include polyester-based elastomers, polyamide-based elastomers, polyurethane-based elastomers obtained by block copolymerization of polyether glycols, polyester-based glycols, polycarbonate-based glycols and the like having a molecular weight of 300 to 5000. These may be used alone or in combination of two or more.

  The content of the heat-fusible elastic fiber (for example, heat-fusible polyurethane elastic fiber) in the knitted fabric can be, for example, 3% by mass or more, preferably 5% by mass or more. The upper limit of the content may be 100% by mass. When the content is less than 3% by mass, the heat fusion effect may be lowered when used as a composite yarn.

  The knitted fabric can be knitted by any appropriate knitting machine. The gauge of the knitting machine (the number of knitting needles between 1 inch) can be appropriately set according to the weight of the target knitted fabric, the knitting density, the fineness of the knitting yarn, and the like. The gauge of the knitting machine is preferably 12 to 45 / 2.54 cm, more preferably 20 to 45 / 2.54 cm. The size of the hook of the knitting machine is preferably 30 to 38 inches.

  The thickness of the knitted fabric layer in the multilayer fiber structure of the present invention can be appropriately set depending on the use and the like. The thickness may be, for example, 0.05 to 3.00 mm, preferably 0.06 to 2.30 mm.

B. Manufacturing method of multilayer fiber structure The multilayer fiber structure of the present invention is obtained by, for example, laminating a web and a knitted fabric (laminating step), and placing the obtained laminate on a porous support so Can be obtained by a production method including spraying (hydroentanglement process) and drying the laminate (drying process). Multi-layer fiber having moderate delamination force while maintaining web flexibility, water absorption, water retention, air permeability and extensibility of knitted fabric by joining web layer and knitted fabric layer by hydroentanglement A structure can be obtained.

B-1. Lamination process In a lamination process, it laminates typically supplying a web and a knitted fabric continuously. The stacking order is appropriately selected according to the structure of the target multilayer fiber structure.

  As the web, for example, a web formed by a card method or an air array method, preferably a card method is used. According to the card method, it is possible to obtain webs having three configurations: a parallel web, a cross-laid web, and a parallel cross-laid web.

  The parallel web is a web as it is spun from the card machine. In a parallel web, since the constituent fibers of the web are arranged so that the longitudinal direction thereof substantially coincides with the flow direction (conveyance direction), a web layer having a high tensile strength in the flow direction and high extensibility in the width direction is provided. Can be obtained. The basis weight of the parallel web is determined by the amount of fibers fed into the card machine. If the fiber feed amount is large, the defibrating effect of the card machine will be reduced, so there may be a decrease in aesthetics due to an increase in nep, and if the fiber feed amount is small, the web will be perforated. Sometimes.

  The cross-laid web is a web obtained by folding a parallel web so as to intersect the flow direction (conveying direction) by a cross wrapper. The cross-laid web can have a tensile strength ratio of 0.5 to 2.0 in the flow direction and the width direction, so that a well-balanced web layer can be obtained. Further, by changing the number of webs to be folded or changing the basis weight of the parallel web, the web can be spun from a low basis weight web to a high basis weight web.

  The cross-laid web immediately after being folded by the cross wrapper may be in a state where the web is folded at a crossing angle smaller than 90 ° and a plurality of sheets are overlapped. The corner can be adjusted. The crossing angle after drafting is preferably 8 to 160 °, more preferably 15 to 110 °. When the crossing angle is less than 8 °, problems such as a thick web layer and a hard multilayer fiber structure may occur. On the other hand, when the angle is larger than 160 °, the web becomes thin, and missing web layers and entanglement spots in the multilayer fiber structure may occur. In addition, this intersection angle means the folding direction (intersection angle of the arrangement direction of the constituent fibers of the web) of the width direction and the web.

  The parallel cross web is a web in which a parallel web and a cross-laid web are laminated. The parallel web may have a lower basis weight at both ends of the web, and the cross-laid web tends to have a heavier basis weight at the both ends of the folded web due to the characteristics of the cross wrapper. There is an advantage that there are few spot spots in the width direction and aesthetics are high.

  The web nep rate is preferably 40 to 3000 pieces / g, more preferably 40 to 1500 pieces / g. When webs with a nep rate exceeding 3000 pieces / g are used, the joining of the web layer and the knitted fabric layer becomes non-uniform, the number of nep layers in the web layer increases, and the aesthetics of the multilayer fiber structure decrease. There is. When a web having a nep rate of less than 40 pieces / g is used, these problems do not occur, but the production cost of the web may increase or the production efficiency may decrease. In order to obtain a web having a low nep rate, it is preferable to use a fixed flat type card machine.

  As the knitted fabric, the knitted fabric described in the above section A-3 can be used. The knitted fabric may be subjected to any appropriate treatment depending on the purpose and the like. For example, the dyeing process facilitates the distinction between the web layer and the knitted fabric layer, and can improve the design of a product using the multilayer fiber structure. Further, for example, when a multilayer fiber structure is used for a cosmetic face mask by hydrophobic treatment or water repellent treatment, leakage of cosmetics and the like from the knitted fabric layer to the outside (air side) can be suppressed. Examples of other treatments include hair roasting, scouring, bleaching, mercerizing, liquid ammonia processing, cellulose cross-linking treatment using a cellulose cross-linking agent, and softener treatment for adjusting the texture.

  When using a weft knitted fabric, it is preferable to arrange the course direction so that it is substantially parallel to the width direction of the multilayer fiber structure. By arranging in this way, a multilayer fiber structure excellent in extensibility can be obtained. Here, “substantially parallel” means an angle including 0 ± 10 °.

  Moreover, when using a knitted fabric of a knitted fabric, it is preferable to arrange a web on the front side of the knitted fabric. Since the knitted fabric is easily curled toward the front side, curling can be reduced by arranging in this way. In addition, the three-layer fiber structure having the configuration of web layer / knitted fabric layer / web layer has a configuration of parallel web layer / knitted fabric layer / cross-laid web layer or cross-laid web layer / knitted fabric layer / cross-laid web layer. Thus, curling can be reduced. Other methods for reducing curl include increasing the basis weight of the web and using a cross-laid web. According to these methods, curling can be reduced by reducing the difference in strength between the flow direction and the width direction of the multilayer fiber structure.

  In the lamination of the three-layer fiber structure, by adopting the configuration of the parallel web layer / knitted fabric layer / cross-laid web layer, for the same reason as in the case of the parallel cross web, there is little unevenness in the width direction, and aesthetics are improved. There is an advantage that an excellent multilayer fiber structure can be obtained.

  In the laminating step, the card web and the knitted fabric are typically laminated. However, if necessary, the card web may be pre-entangled to form a nonwoven fabric, and the nonwoven fabric and the knitted fabric may be laminated. .

B-2. Hydroentanglement process In the hydroentanglement process, the laminate obtained in the lamination process is placed on a porous support, and a high-pressure liquid stream is jetted onto the laminate. Thereby, the fibers in the web and the constituent fibers of the web and the knitting yarn of the knitted fabric are entangled, and the web layer and the knitted fabric layer are integrated. In the case of a two-layer fiber structure, the laminate is preferably arranged so that the knitted fabric is on the support side, and a liquid flow is jetted from the web layer side to the knitted fabric layer side at a relatively low hydraulic pressure, Prevent scattering. The high pressure liquid stream can be jetted from above and / or below the laminate.

  The porous support is preferably a support having a smooth surface, and examples thereof include plain weave or twill wire mesh. The mesh opening is preferably 20 to 100 mesh, more preferably 50 to 90 mesh. Further, the numbers of warps and wefts are preferably 20 to 110 yarns / 2.54 cm, respectively. When the mesh opening is larger than 20 mesh, the porosity of the support becomes high, so that the constituent fibers of the web enter the woven structure of the support, thereby deteriorating the peeling between the support and the multilayer fiber structure, Wrinkles and fluffing may occur. On the other hand, if the mesh opening is finer than 100 mesh, sufficient entanglement cannot be obtained, which may lead to a decrease or variation in the strength and delamination force of the multilayer fiber structure.

The maximum liquid pressure of the high-pressure liquid flow is preferably 5 × 10 ^{5 to} 180 × 10 ⁵ Pa, more preferably 5 × 10 ^{5 to} 150 × 10 ⁵ Pa. When the hydraulic pressure is less than 5 × 10 ⁵ Pa, the energy used is reduced, but the delamination force may be lowered, or the surface of the web layer may be noticeable. On the other hand, when the hydraulic pressure exceeds 180 × 10 ⁵ Pa, problems such as delamination force and entanglement between fibers in the web layer become too high and the multilayer fiber structure becomes hard may occur.

  The liquid to be ejected is not limited as long as the fiber to be treated is insoluble, but usually water or warm water is used.

  The nozzle diameter of the nozzle from which the high-pressure liquid flow is injected is preferably 80 to 200 μm, more preferably 100 to 150 μm. The interval between the nozzles is preferably 0.5 to 2.0 mm, more preferably 0.6 to 1.0 mm.

  The nozzles are arranged in one or a plurality of rows in a direction orthogonal to the flow direction (transport direction) of the laminate. The number of nozzles and the number of hydroentanglements (number of times of jetting liquid) can be appropriately adjusted according to the basis weight and type of the laminate of the web and the knitted fabric, the processing speed, the hydraulic pressure, and the like.

  In the hydroentanglement process, for the purpose of imparting various uneven structures or three-dimensional patterns to the multilayer fiber structure, the laminate is placed on a support having an appropriate opening pattern and subjected to hydroentanglement treatment, support It is possible to arrange an appropriate three-dimensional shape on the body and perform a hydroentanglement process by stacking a laminate thereon.

  The laminating step and / or the hydroentanglement step may be repeated a plurality of times. For example, a web and a knitted fabric can be laminated | stacked, a hydroentanglement process can be performed to this laminated body, a web can further be laminated | stacked on a web layer, and a hydroentanglement process can be performed again here. Further, for example, the web and the knitted fabric may be laminated and hydroentangled on the laminate, and then the laminate may be turned over, and the web may be laminated on the knitted fabric layer and the hydroentangled treatment may be performed again. .

B-3. Drying step In the drying step, the laminate integrated in the hydroentanglement step is dried. Thereby, the multilayer fiber structure of the present invention can be obtained. Any appropriate means can be adopted as the drying means. For example, after removing excess liquid by a method such as suction or wet pressing, drying can be performed by using an air dryer, a cylinder dryer, an air-through dryer, a suction dryer, or the like.

B-4. Other process The manufacturing method of the multilayer fiber structure of this invention may further include another process as needed. For example, since the multilayer fiber structure of the present invention is typically formed in a long shape, a step of winding it and a step of cutting it into a desired shape can be included. In addition, for example, when the knitted fabric includes heat-fusible elastic fibers, the heat-fusible property can be obtained by heating the knitted fabric before the laminating step or heating the multilayer fiber structure after the drying step. Elastic fibers can be heat-sealed. As a heating condition, it can set appropriately according to the kind etc. of the heat-fusible elastic fiber to be used. Further, the bonding between the web layer and the knitted fabric layer may be strengthened by another entanglement process such as a needle punch or an adhesive process using any appropriate adhesive, heat-fusible fiber, or the like.

  In addition, as a post-processing of the multilayer fiber structure, the obtained multilayer fiber structure is stretched in the flow direction to partially reduce or cut the entanglement of the web layer. When a knitted fabric containing fibers is used, the stretchability in the flow direction and the stretch recovery property can be enhanced. Furthermore, embossing and post-processing that imparts wavy or bowl-shaped irregularities can also be performed.

C. Textile product The textile product of the present invention includes the multilayer fiber structure. For example, face products, puffs, makeup removal sheets, etc. for textile products for beauty use; trousers, jackets, gowns, underwear, shoulder pads, interlining, cushion materials, disposable uniforms, etc. for textile products; Disposable diapers, sanitary products, etc .; disposable gowns, bandages, compresses, masks, gauze, etc .; textile products for other uses such as air filters, filter sheets, sludge filters, Examples include wallpaper, interior materials, heat insulating materials, packaging materials, and synthetic leather base fabrics.

  In one preferred embodiment, the textile product of the present invention is a cosmetic face mask. For example, the face mask for cosmetics cuts the multilayer fiber structure composed of a knitted fabric layer and a web layer along the contour of the face, cuts out the portions corresponding to both eyes and mouth, and provides fit to the nose and cheek portions. Can be obtained by making incisions to enhance. The face mask may be sold as it is in a container, or a face mask impregnated with lotion or the like may be sold in a container. At the time of use, it is preferable that the web layer is brought into contact with the skin side, the knitted fabric layer is placed outside, and the web layer is stuck along the face in a slightly stretched state. Since the multilayer fiber structure is excellent in extensibility, a face mask that extends along the unevenness of the face and has high fit can be obtained. Moreover, since the curl of the cut portion is small, it is difficult to peel off from the skin, and the web layer is flexible and has high water retention, so that a comfortable feeling of use can be obtained. When the multilayer fiber structure is cut along the face contour, the flow direction of the multilayer fiber structure and the length direction of the face can be cut at any suitable angle. For example, the extensibility and curl degree of the face mask obtained by cutting so that the flow direction of the multilayer fiber structure and the length direction of the face are orthogonal or parallel or at an angle of 45 degrees Can be adjusted.

  In another preferred embodiment, the textile product of the present invention may be a puff or makeup remover sheet. These are used by being affixed to the skin or the like in a state of being impregnated with a cosmetic containing, for example, a moisturizing component, a cleansing component, an ultraviolet absorption preventing component, an antiperspirant component, a scent component, a whitening component, a blood circulation promoting component and the like. The cosmetic may be impregnated in advance as part of the fiber product, or may be applied immediately before use.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited by these Examples. The measurement methods and evaluation methods used in the examples are as follows.

[Elongation]
The elongation was measured according to the method described in JIS L 1096. Details are as follows.
・ Elongation of multi-layer fiber structure Samples of 5 cm × 20 cm were taken at 5 points each so that the width or flow direction was long, and stretched at a gripping interval of 10 cm and a tensile speed of 20 cm / min. Elongation is measured and calculated by the following formula. The elongation is expressed as an average value of each measurement value. Visual recognition is performed when the web layer breaks.
Elongation (%) = [Holding length when web layer breaks−Initial holding length (cm)] / [Initial holding length (cm)] × 100
・ Elongation of knitted fabric Samples of 5cm x 20cm are taken at 5 points each so that the course direction or the wale direction is the long side, stretched at a gripping interval of 10cm and a tensile speed of 20cm / min, and stretched when the knitted fabric broke Is calculated by the following formula. The elongation is expressed as an average value of each measurement value.
Elongation (%) = [gripping length at the time when the knitted fabric breaks-initial gripping length (cm)] / [initial gripping length (cm)] × 100

[Constant load elongation]
The 14.7N constant load elongation of the multilayer fiber structure was measured according to the method described in JIS L 1096. Specifically, a sample of 5 cm × 20 cm is taken with 5 points each so that the width or the flow direction becomes a long side, and the elongation to the point of load 14.7 N is measured at a gripping interval of 10 cm and a tensile speed of 20 cm / min. Calculate with the following formula. The constant load elongation is expressed as an average value of each measured value.
Constant load elongation (%) = [grip length at 14.7 N load of multilayer fiber structure−initial grip length (cm)] / [initial grip length (cm)] × 100

[Elongation recovery rate]
The elongation recovery rate was measured based on the method described in JIS L 1096. Specifically, a sample of 5 cm × 30 cm is taken at three points each so that the width or the flow direction becomes the long side, and is gripped for 30 seconds while being stretched by 30% at a gripping interval of 20 cm and a pulling speed of 20 cm / min. The sample was allowed to stand for 1 hour in a state where the elongation was stopped, and then the length of the sample was measured to calculate the elongation recovery rate.

[Delamination strength]
Two samples each having a length of 5 cm × 20 cm are prepared so that the width or the flow direction becomes the long side, and two layers to be measured are peeled from one end in the longitudinal direction of the sample to the center by hand. Next, two layers (for example, a web layer, a knitted fabric layer, and a knitted fabric layer in the case of a two-layer fiber structure) peeled to the gripping portion of a tensile testing machine (Orientec Co., Ltd., model name Tensilon RTA-100, load 980 N) In the case of a three-layer fiber structure in which a web layer is disposed on both sides of the web layer, the web layer on one side and the remaining two layers, and in the case of a three-layer fiber structure in which a knitted fabric layer is disposed on both sides of the web layer, Each of the knitted fabric layer and the remaining two layers) is measured, and the maximum peeling force when the gripping interval is 10 cm and the tensile speed is 20 cm / min is measured, and the peeling force in the width and the flow direction is calculated as an average value of two times. . Further, in the case of a three-layer fiber structure, the peeling force of the remaining two layers is measured by the same method as described above. In the present invention, the higher value of the peeling force in the width and flow direction is adopted as the delamination force. In the case of a three-layer fiber structure, the delamination force between the two layers having the higher delamination force is measured first, and then the delamination force between the remaining two layers is measured (preliminary if necessary) Measurement may be performed to determine in advance which delamination force is higher).

[Mixing ratio of web constituent fibers in the knitted fabric layer]
The knitted fabric layer and the web layer are peeled by the same method as the measurement of the delamination force, and the calculation is performed based on the difference between the initial fabric weight of the web layer and the fabric weight after peeling.

[Curl degree]
A sample of 2.5 cm × 16 cm is taken each so that the width or the flow direction becomes the long side, and is stretched 10% at a gripping interval of 3 cm and a tensile speed of 20 cm / min, and this is repeatedly expanded and contracted five times. Next, the sample width after extension: X (cm) is measured by the projection method, and calculated from the following equation.
Curling degree (%) = (2.5−X) /2.5×100

[Bending softness]
The bending resistance (softness) was measured according to the method described in JIS L 1096. Specifically, a sample of 2.0 cm × 15 cm is sampled at five points so that the width or the flow direction becomes the long side, and is represented by an average value obtained by cantilever type measurement.

[Thickness]
-Thickness of multilayer fiber structure and knitted fabric (layer) Using a thickness measuring machine (trade name: THICKNESS GAUGE model CR-60A, manufactured by Daiei Kagaku Seisakusho Co., Ltd.) with a load of 4 cN per 1 cm ^{2 of} sample. It was measured. Moreover, the thickness of the knitted fabric layer in the multilayer fiber structure was a thickness obtained by measuring the used knitted fabric by the method.
・ Thickness of the web layer in the three-layer fiber structure in which the knitted fabric layer is arranged on both sides of the two-layer fiber structure and the web layer. The thickness of these web layers is the thickness of the knitted fabric used from the thickness of the multilayer fiber structure. Calculate by subtracting.
-Thickness of each web layer in the three-layer fiber structure in which the web layers are arranged on both sides of the knitted fabric layer Measured by the following method using a stereomicroscope.
(1) Cut the three-layer fiber structure into a 5 mm square in a direction that forms an angle of 45 degrees with the flow direction and the width direction (the cut is a sharp blade, for example, the trade name “Disposmes No11” (manufactured by ASONE Co., Ltd.)). Use) to make a sample. Prepare 5 or more samples.
(2) The section (thickness direction) of the cut sample is magnified (for example, 50 to 200 times) using an optical stereomicroscope (trade name “SZ61”, manufactured by OLYMPUS) and photographed. For photographing, a digital camera (trade name “μ-mini DIGITAL”, manufactured by OLYMPUS) is used and photographed by a collimating method at a magnification of 1.0.
(3) A 5 mm / 100 scale on a microscale (trade name “Microscale Slide 177-401C”, manufactured by Watson Co., Ltd.) is magnified and photographed at the same magnification as the sample using the optical stereomicroscope. For photographing, a digital camera (trade name “μ-mini DIGITAL”, manufactured by OLYMPUS) is used and photographed by a collimating method at a magnification of 1.0.
(4) The photographed material of (2) and (3) above is printed, the thickness of the web layer is measured at 7 locations, and the average value of the 5 locations excluding the maximum and minimum values is calculated as the web Let it be the thickness of the layer.
(5) For five or more samples, the thickness is measured in the same manner as described above, and all average values are calculated to obtain the thickness of the web layer of the multilayer fiber structure.

[Apparent density]
The apparent density of the web layer is calculated from the basis weight and thickness of the web layer.

[Initial extension force (5% load)]
The measurement was performed according to the method described in JIS L 1096. Specifically, a sample of 5.0 cm × 20 cm is taken with 5 points each so that the width or the flow direction becomes a long side, and a value measured at a gripping interval of 10 cm and a tensile speed of 20 cm / min is expressed as an average.

[Weight per unit]
The measurement was performed according to the method described in JIS L 1096. Specifically, five samples of 30 cm × 30 cm are taken, each sample is measured with a direct balance, converted to a weight per 1 m ² , and expressed as an average value.

[Whiteness]
Rd and + b are indices representing the whiteness of cotton measured by Worcester's raw cotton tester “USTER HVI”. Rd represents the brightness of the color, and 100% is the upper limit value. + B is an index indicating the degree of yellowness of the color.

[Production Example 1-A]
A 30 inch (2.54 cm / inch), 28 gauge single knitting machine was used. A 100% cotton yarn with an English cotton count of 60 is used as the knitting yarn, and a knitted fabric A having a woven fabric with a basis weight of 80 g / m ² , a course density of 55 / 2.54 cm, and a wale density of 50 / 2.54 cm is obtained. It was. The elongation of the knitted fabric A in the course direction was 283%, the elongation in the wale direction was 37%, and the thickness was 0.346 mm.

[Production Example 1-B]
A 38 inch, 19 gauge double knitting machine was used. Milling knitted fabric B with a weight of 80 g / m ² , a course density of 43 / 2.54 cm, and a wale density of 36 / 2.54 cm is obtained using 100% cotton yarn of English cotton count 80 as the knitting yarn. It was. The elongation of the knitted fabric B in the course direction was 496%, the elongation in the wale direction was 60%, and the thickness was 0.384 mm.

[Production Example 1-C]
A 26 inch, 22 gauge single knitting machine was used. As a knitting yarn, SCY (The heat-bonding polyurethane elastic fiber of the core yarn is a heat-fusible Mobilon yarn RL type manufactured by Nisshinbo Textile Co., Ltd. (fineness 44 dtex 1 filament, elongation ratio 2.3 times, brown original yarn) The brown original yarn was obtained by kneading 0.2% CROMOPHTAL Brown 5R (made by BASF Japan) with respect to the mass of the yarn, and the sheath yarn was Woolley nylon (fineness) made by Toray Industries, Inc. 12 dtex5 filament, twist number 600 T / m), and a heat-sealable polyurethane elastic fiber mixture ratio of 59.5% and covering ratio of 6%) was used to obtain a knitted fabric with a woven fabric. Next, using a tenter machine, the knitted fabric was heat-treated at 150 ° C. for 1 minute in a state of extending 1.46 times in the course direction. Thereby, the heat-fusible core yarn in SCY was completely heat-sealed at these intersecting portions, and was fused to such an extent that the boundaries of the intersecting portions disappeared. The core yarn was greatly deformed at the intersection of the core yarn and the sheath yarn in SCY, and the sheath yarn was incorporated so as to be buried in the core yarn. The obtained knitted fabric C had a basis weight of 40 g / m ² , a coarse density of 68 / 2.54 cm, and a wale density of 58 / 2.54 cm. Further, the elongation in the course direction was 484%, the elongation in the wale direction was 393%, and the thickness was 0.464 mm.

The mixing ratio of the heat-fusible polyurethane elastic fibers in the SCY is a value calculated by the following equation (1), and the coverage of the SCY is a value calculated by the following equation (2).
Polyurethane elastic fiber mixing ratio (%) = (PU / DR) / ((PU / DR) + D) × 100 (1) Formula C = (0.012 × √D × T / (1000 / DR)) × 100 (2) where C is the covering rate (%), PU is the fineness (decitex) of the heat-sealable polyurethane elastic fiber, and D is the non-covering amount around the heat-sealable polyurethane elastic fiber. The fineness (decitex) of the heat-fusible fiber, T represents the number of twists (T / m) during twisting, and DR represents the stretch ratio (times) of the polyurethane elastic fiber during covering or twisting.

[Production Example 1-D]
A 38 inch, 19 gauge double knitting machine was used. Milling knitted fabric D having a weight per unit area of 50 g / m ² , a course density of 33 / 2.54 cm, and a wale density of 28 / 2.54 cm is obtained using 100% cotton yarn of British cotton count 80 as the knitting yarn. It was. The elongation of the knitted fabric D in the course direction was 300%, the elongation in the wale direction was 70%, and the thickness was 0.290 mm.

[Production Example 1-E]
A 38 inch, 40 gauge double knitting machine was used. As the knitting yarn, 100% cotton yarn of English cotton count 80 was used to obtain a milled knitted fabric E having a basis weight of 120 g / m ² , a course density of 75 / 2.54 cm, and a wale density of 66 / 2.54 cm. . The elongation of the knitted fabric E in the course direction was 115%, the elongation in the wale direction was 20%, and the thickness was 0.395 mm.

An outline of the knitted fabrics A to E is shown in Table 1.

[Production Example 2]
Cotton short fibers (average fiber length 28 mm, diameter 18 μm) were used as the constituent fibers of the web. First, impurities were removed and opened and spread through a mixed cotton carding process, followed by a bleaching treatment using hydrogen peroxide. Subsequently, opening and carding were performed through a cotton carding process to obtain a card web having a whiteness of Rd of 96%, + b of +0.2, and a nep rate of 70 pieces / g.

[Examples 1-6, Comparative Examples 1-7]
The knitted fabric and the web were laminated under the conditions shown in Table 2 and Table 3, and hydroentangled. After dehydrating and drying the laminate after the hydroentanglement treatment, a multilayer fiber structure was obtained through a winding process. The properties of the obtained multilayer fiber structure are shown in Table 2 and Table 3. In addition, the lamination | stacking method and hydroentanglement method of a web and a knitted fabric are as follows.

[Lamination method of web and knitted fabric]
(Lamination of two-layer fiber structure of cross-laid web and knitted fabric)
The card web of Production Example 2 was passed through a cross wrapper and laminated on the knitted fabric as a cross-laid web. At this time, the course direction of the knitted fabric (the weft direction of the knitted fabric) was set to be a direction orthogonal to the conveying direction. The laminate was placed on a support (mesh 90 mesh twill) so that the knitted fabric layer was on the support side and subjected to hydroentanglement treatment.
(Lamination of two-layer fiber structure of parallel web and knitted fabric)
The card web of Production Example 2 was laminated on the knitted fabric as a parallel web without passing through the cross wrapper. At this time, the course direction of the knitted fabric was set to be a direction orthogonal to the conveyance direction. The laminate was placed on a support (mesh 90 mesh twill) so that the knitted fabric layer was on the support side and subjected to hydroentanglement treatment.
(Lamination of three-layer fiber structure)
A knitted fabric was inserted between the cross-laid web of Production Example 2 (weight per unit area: 17 g / m ² ) and parallel web (weight per unit area: 12 g / m ² ) prepared using two cards. At this time, the course direction of the knitted fabric was set to be a direction orthogonal to the conveyance direction. In addition, the laminate was placed on a support (mesh 90 mesh twill net) so that the parallel web was on the support side and subjected to hydroentanglement treatment.

[Water entanglement method]
(Front processing)
Above the laminate on the support, a high-pressure water current launching device (the diameter of the injection port is 100 μm or 120 μm, and the interval between the injection ports is 0.6 mm) is prepared. The water flow was jetted at the water pressure described in.
(Rear processing)
The laminate on the support was turned upside down and placed on another support (twill mesh with a mesh opening of 90 mesh). Next, a high-pressure water current launching device (the diameter of the injection port is set to 100 μm or 120 μm, and the interval between the injection ports is set to 0.6 mm) is prepared above the laminate, and described in Tables 2 and 3 for the laminate. The water flow was jetted at a water pressure of.
Here, after the front treatment, the rear treatment is performed, and the case where the hydroentanglement treatment is performed once on both surfaces of the laminate is counted as one cycle. When this one cycle is repeated twice, two cycles are performed. And count. When only one of the front process and the rear process is performed, 0.5 cycle is counted.

  As shown in Table 2 and Table 3, it can be seen that the multilayer fiber structures of Examples 1 to 6 are excellent in extensibility and integrated with an appropriate delamination force. The multilayer fiber structure of Example 2 obtained under the hydroentanglement condition weaker than that of Example 1 has a higher delamination force than that of Example 1. This is probably because the knitted yarn of the knitted fabric and the constituent fibers of the web layer were strongly entangled because the knitted density of the used knitted fabric was low. In Example 3, there was no need to stop the process once during the production and adjust the dimensions of the knitted fabric, and the production process was excellent in stability. In addition, a highly uniform multi-layer fiber structure was obtained with less thickness unevenness, width variation and surface unevenness due to curling and shrinkage of the knitted fabric. Furthermore, by performing post-processing, a multilayer fiber structure having high extensibility in the flow direction was obtained. Specifically, post-processing increases the elongation in the flow direction from 50% to 70%, the initial stretching force (5% load) decreases from 1.7N to 0.9N, and the 14.7N constant load elongation. Increased from 26% to 44%. Moreover, the multilayer fiber structure of Example 6 is compatible with the elongation in the width direction and the delamination force at a high level.

On the other hand, the multilayer fiber structures of Comparative Examples 1 to 7 all had an elongation in the width direction of less than 50%. In Comparative Examples 1 and 4, since the apparent density of the web layer is lower than 0.065 g / cm ³ , it is considered that the joining of the knitted fabric layer and the web layer and the entanglement between the constituent fibers of the web layer are weak. In Comparative Examples 2 and 3, since the apparent density of the web layer is higher than 0.170 g / cm ³ , it is considered that the elongation decreased due to strong entanglement between the constituent fibers of the web layer. In Comparative Example 5 using a knitted fabric with a low knitting density, a large amount of the constituent fibers of the web layer gathered around the knitting yarn of the knitted fabric, and the portion looked white. Further, it was confirmed from the hand that the constituent fibers of the web layer and the knitting yarn of the knitted fabric were strongly entangled in the portion. On the other hand, there were few webs arrange | positioned on the clearance gap of the loop of a knitted fabric, it was in the state seen through from the back side, and the web layer was non-uniform | heterogenous. At the stage where the multilayer fiber structure of Comparative Example 5 was stretched by 40% in the width direction, the web layer was broken at a portion where the web was small, and a pinhole was generated. In Comparative Example 6, a knitted fabric with a low knitting density is used as in Comparative Example 5, but as a result of strengthening the hydroentanglement conditions, the joining of the knitted fabric layer and the web layer becomes stronger, and the constituent fibers of the web layer are mutually bonded. Was also entangled strongly. However, fewer webs were placed over the gaps in the loop of the knitted fabric, and the thickness unevenness of the web layer increased. At the stage where the multilayer fiber structure of Comparative Example 6 was stretched by 40% in the width direction, the web layer was broken at a portion where the web was small, and pinholes were generated. The number of pinholes was larger than that of Comparative Example 5. In Comparative Example 7 using a knitted fabric with high knitting density, it was impossible to achieve both elongation and delamination force.

[Test Example 1]
Cut the multilayer fiber structures of Examples 1 to 6 and Comparative Examples 1 to 3 and 5 along the outline of the face, cut out the parts corresponding to both eyes and mouth, and cut into the nose and cheek parts to make a face mask Produced. The width direction of the web layer is the lateral direction of the face, and the machine direction of the web layer is the length direction of the face. Table 4 shows the curl degrees of the face masks prepared from the multilayer fiber structures of Examples 1 to 6.

  When the obtained face mask was brought into contact with the face so that the web layer was on the skin side, the face mask produced from the multilayer fiber structure of the example had higher extensibility and flexibility than that of the comparative example and was used. The feeling was excellent. Further, as shown in Table 4, each face mask had a curl degree of less than 40% (all less than 10% in the length direction), and was not peeled off from the skin during use. In particular, the multilayer fiber structure of Example 3 has an initial stretching force (5% load) in the flow direction of less than one-tenth of the multilayer fiber structure of the other examples. It has the characteristics of being easy to stretch at low loads. Therefore, it was possible to adhere very quickly compared to the face masks of other examples and comparative examples. In addition, since a knitted fabric with heat-sealable polyurethane elastic fibers heat-sealed is used, the cut portion is less likely to fray than other face masks, and there is no scattering of small pieces of the knitted fabric. there were. Moreover, the face mask produced from the multilayer fiber structure of Example 6 was excellent in extensibility and good results without separation of the two layers during use.

  On the other hand, the face mask produced from the multilayer fiber structure of Comparative Example 1 was unpleasant with tingling skin. The face masks made from the multilayer fiber structures of Comparative Examples 2 and 3 were uncomfortable because they felt insufficient stress to contact the skin due to lack of elongation, and because they were hard, the skin was stressed during use. . When the face mask made from the multilayer fiber structure of Comparative Example 5 was impregnated with the liquid cosmetic, the cosmetic flowed to the outside from the thin transparent portion of the web layer. Further, if the amount of liquid cosmetic impregnated is small, the amount of cosmetic retained in the thin transparent portion of the web layer is small, which is undesirable because the skin treatment becomes uneven.

  The multilayer fiber structure of the present invention can be suitably used for various fiber products such as a cosmetic face mask.

100 multilayer fiber structure 10 web layer 11 knitted fabric layer

Claims (10)

A web layer containing 20% by mass or more of cellulose fibers, an apparent density of 0.065 to 0.170 g / cm ³ , a course density of 35 to 73 / 2.54 cm, and a wale density of 30 to 64/2. And a knitted fabric layer having a basis weight of 10 to 120 g / m ² ,
The web layer and the knitted fabric layer are integrated by hydroentanglement treatment,
A multilayer fiber structure having an elongation in the width direction of 50 to 200%.   The multilayer fiber structure of Claim 1 whose delamination force of the said web layer and the said knitted fabric layer is 0.5-10.0N.   The multilayer fiber structure according to claim 1 or 2, wherein the web layer comprises a cotton web having a brightness index (Rd) of 90 to 100% and a yellowness index (+ b) of -2.0 to 1.0. object.   The multilayer fiber structure according to any one of claims 1 to 3, wherein an average fiber length of constituent fibers of the web layer is 13 to 51 mm.   The multilayer fiber structure according to any one of claims 1 to 4, wherein the knitted fabric layer includes heat-fusible elastic fibers.   The multilayer fiber structure according to any one of claims 1 to 5, which is a two-layer fiber structure.   The multilayer fiber structure according to any one of claims 1 to 5, which is a three-layer fiber structure in which the web layer is disposed on both surfaces of the knitted fabric layer.   The multilayer fiber structure according to any one of claims 1 to 5, which is a three-layer fiber structure in which the knitted fabric layer is disposed on both surfaces of the web layer.   A textile product comprising the multilayer fiber structure according to any one of claims 1 to 8. The textile product according to claim 9, which is a face mask.