Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
  • B32B5/22—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed
  • B32B5/24—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer
  • B32B5/26—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer another layer next to it also being fibrous or filamentary
  • B32B5/262—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer another layer next to it also being fibrous or filamentary characterised by one fibrous or filamentary layer being a woven fabric layer
• • A—HUMAN NECESSITIES
  • A41—WEARING APPAREL
  • A41D—OUTERWEAR; PROTECTIVE GARMENTS; ACCESSORIES
  • A41D13/00—Professional, industrial or sporting protective garments, e.g. surgeons' gowns or garments protecting against blows or punches
  • A41D13/05—Professional, industrial or sporting protective garments, e.g. surgeons' gowns or garments protecting against blows or punches protecting only a particular body part
  • A41D13/11—Protective face masks, e.g. for surgical use, or for use in foul atmospheres
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F13/00—Bandages or dressings; Absorbent pads
  • A61F13/15—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators
  • A61F13/51—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the outer layers
  • A61F13/511—Topsheet, i.e. the permeable cover or layer facing the skin
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
  • B32B5/14—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by a layer differing constitutionally or physically in different parts, e.g. denser near its faces
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
  • B32B5/22—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed
  • B32B5/24—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer
  • B32B5/26—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer another layer next to it also being fibrous or filamentary
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
  • D04H1/42—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties characterised by the use of certain kinds of fibres insofar as this use has no preponderant influence on the consolidation of the fleece
  • D04H1/4374—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties characterised by the use of certain kinds of fibres insofar as this use has no preponderant influence on the consolidation of the fleece using different kinds of webs, e.g. by layering webs
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2250/00—Layers arrangement
  • B32B2250/20—All layers being fibrous or filamentary
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2262/00—Composition or structural features of fibres which form a fibrous or filamentary layer or are present as additives
  • B32B2262/02—Synthetic macromolecular fibres
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2307/00—Properties of the layers or laminate
  • B32B2307/70—Other properties
  • B32B2307/726—Permeability to liquids, absorption
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2555/00—Personal care
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2555/00—Personal care
  • B32B2555/02—Diapers or napkins

Definitions

• the present invention relates to a laminated nonwoven fabric particularly suitable for sanitary material applications and sanitary materials using the same.
• the key to comfort is to quickly remove water such as urine and sweat and keep the surface of the member dry.
• Patent Document 1 proposes a non-woven fabric in which a fiber layer made of fine fine fibers (skin surface side) and a fiber layer made of thick fine fibers are laminated and partially entangled at a boundary surface. .. Further, in Patent Document 2, sheets having different average fiber unoccupied voids due to the difference in the mixing ratio of a plurality of fibers and the fiber diameter are laminated, and the average fiber unoccupied voids of the first layer that come into contact with the skin are made from the layers other than the first layer. A larger sheet has been proposed.
• an object of the present invention is to provide a laminated nonwoven fabric having sufficient quick-drying property and excellent water absorption in order to maintain comfort in a member using a nonwoven fabric for protective materials.
• the present inventors have a dense structure in the fiber layer made of fine fibers on the skin surface side with respect to the other layers, so that moisture remains in the fiber layer on the skin surface side. It is easy to obtain "quick-drying", and further, the dense fiber layer on the skin surface reduces the liquid permeability, and it is not possible to absorb water quickly, so that "water absorption" is obtained. I found it difficult.
• the average fiber non-occupied void disclosed in Patent Document 2 indicates the total volume of the space occupied by other than the fiber, the present inventors do not indicate the size of the void between the fibers, which is important for capillary force. However, even if there is a difference between the layers, the difference in the capillary force does not occur. In particular, in Patent Document 2, the size of the interfiber voids in the layer other than the skin surface is large, so that the capillary force cannot be sufficiently drawn out. It was found that the transfer of water from the skin surface had a limited effect, and the "quick-drying property" was insufficient.
• the present inventors have controlled the interfiber void size in a specific range in consideration of the fiber diameter in addition to the texture and thickness in the specific nonwoven fabric layer in the laminated nonwoven fabric. By doing so, it was found that a laminated non-woven fabric having sufficient water absorption and quick-drying property to be used as a non-woven fabric for protective materials can be obtained.
• the present invention is a laminated nonwoven fabric in which a nonwoven fabric layer made of a thermoplastic resin fiber is laminated, and is calculated by the following formula (1) in the nonwoven fabric layer (A) having the smallest average single fiber diameter among the nonwoven fabric layers.
• Ta Thickness ( ⁇ m) of the non-woven fabric layer (A) da: Fineness (dtex) of the thermoplastic resin fiber constituting the non-woven fabric layer (A) Wa: Metsuke of the non-woven fabric layer (A) (g / m 2 ) Da: The average single fiber diameter ( ⁇ m) of the thermoplastic resin fibers constituting the nonwoven fabric layer (A).
• the present invention is a sanitary material composed of at least a part of the laminated nonwoven fabric of the present invention.
• the laminated nonwoven fabric of the present invention is formed by laminating a nonwoven fabric layer made of a thermoplastic resin fiber.
• thermoplastic resin fiber refers to a fiber made of a thermoplastic resin.
• a thermoplastic resin may be one kind or may be made of a plurality of thermoplastic resins.
• thermoplastic resin used for the thermoplastic resin fiber in the present invention Aromatic polyester polymers such as polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyhexamethylene terephthalate and their copolymers, Polylactic acid, polyethylene succinate, polybutylene succinate, polybutylene succinate adipate, polyhydroxybutyrate-polyhydroxyvariate copolymer, aliphatic polyester polymers such as polycaprolactone and their copolymers, Polyamide 6, polyamide 66, polyamide 610, polyamide 10, polyamide 12, polyamide 6-12 and other aliphatic polyamide polymers and copolymers thereof, Polyolefin-based polymers such as polypropylene, polyethylene, polybutene, and polymethylpentene and their copolymers, A water-insoluble ethylene-vinyl alcohol copolymer polymer containing 25 mol% to 70 mol% of ethylene units, Polystyrene-based
• thermoplastic resins various additives such as inorganic substances such as titanium oxide, silica and barium oxide, carbon black, colorants such as dyes and pigments, flame retardants, fluorescent whitening agents, antioxidants, and ultraviolet absorbers are added.
• the agent may be contained.
• thermoplastic resin constituting the thermoplastic resin fiber may be the same or different between the layers of the nonwoven fabric.
• the thermoplastic resin fiber in the present invention may be a composite fiber in which two or more kinds of resins are combined, as well as a single component fiber.
• thermoplastic resin fiber is a composite fiber, it is not particularly limited as long as the effect of the present invention is not impaired, and it may be appropriately selected from a core sheath type, a sea island type, a side-by-side type, an eccentric core sheath type and the like. .. Further, a split fiber type composite fiber in which a part or the whole of the fiber is divided into a plurality of fibers from one fiber may be used.
• the cross-sectional shape of the thermoplastic resin fiber of the present invention is not particularly limited as long as the effect of the present invention is not impaired, and may be a deformed cross-section such as a triangular, flat, hexagonal, or hollow cross-section as well as a round cross-section. ..
• a round cross section is preferable because it has high productivity and excellent flexibility.
• Step 1 Collect a 5 cm x 5 cm sample piece from the laminated non-woven fabric. At this time, avoid the part where the texture is poor and the thickness is thin.
• Step 2 Take a 3D image of the sample piece obtained in Step 1 with a high-resolution 3D X-ray microscope.
• the measurement resolution may be as long as the diameter of the fiber of each nonwoven fabric layer can be specified, but is preferably 1.0 ⁇ m / voxel or less.
• the image is taken so as to include the center point between the embossed points, that is, the center of the convex portion left by the embossing within the imaging range of the X-ray CT image.
• Procedure 3 From the 3D image taken in step 2, an area of 0.5 mm ⁇ 0.5 mm is extracted as an area to be analyzed.
• the region to be analyzed is extracted so as to include the center point between the embossed points.
• Step 4 For the area to be analyzed extracted in step 3, slice (cross-section) images perpendicular to the thickness direction of the laminated nonwoven fabric and parallel to each other are created at intervals of 1 voxel.
• Step 5 Analyze the fiber diameters of all the fibers contained in each slice image obtained in step 4, calculate the average value, and use it as the provisional average fiber diameter.
• Step 6 Position the laminated non-woven fabric of each slice image created in step 4 in the thickness direction on the x-axis (unit: ⁇ m), and set the provisional average fiber diameter of each slice image obtained in step 5 on the y-axis (unit: ⁇ m). Plot to get a graph.
• Step 7 In the graph obtained in step 6, the rate of change ⁇ y / ⁇ x of the y-axis value with respect to the x-axis is calculated from continuous 15 voxel data by the least squares method, and the absolute value is 0.30 or more on the x-axis.
• the upper section is specified as the position of the interface between the laminated layers of the non-woven fabric layers.
• Nonwoven fabric layer (A) The nonwoven fabric layer (A) in the laminated nonwoven fabric of the present invention is defined as having the smallest average single fiber diameter among the nonwoven fabric layers constituting the laminated nonwoven fabric.
• the average single fiber diameter of each non-woven fabric layer is obtained as follows.
• Step 1 The cross section in the thickness direction is photographed with a scanning electron microscope (SEM) at a magnification that allows the entire thickness direction of the laminated nonwoven fabric to fall within the imaging range.
• SEM scanning electron microscope
• Procedure 2 The position information of the laminated interface obtained by "Procedure for specifying the laminated interface” is applied to the cross-sectional photograph obtained in step 1.
• step 7 of the "Procedure for specifying the laminated interface the section on the x-axis where the absolute value of ⁇ y / ⁇ x is 0.30 or more is defined as the section of the laminated interface, and the section divided by the section of the laminated interface is defined as each section.
• the section for analysis of the non-woven fabric layer is defined as the section for analysis of the non-woven fabric layer.
• Step 3 The area Af ( ⁇ m 2 ) formed by the cross-sectional contour of the single fiber is measured using image analysis software for the analysis section of each non-woven fabric layer specified in step 2, and is the same as this area Af. Calculate the diameter of a perfect circle that is the area. This is measured for 20 single fibers randomly selected from the same analysis section, the arithmetic mean is calculated, the unit is ⁇ m, and the second decimal place is rounded off to obtain the average single fiber diameter.
• the average single fiber diameter Da of the thermoplastic resin fibers constituting the nonwoven fabric layer (A) is preferably 20.0 ⁇ m or less. By setting Da to 20.0 ⁇ m or less, more preferably 15.0 ⁇ m or less, the interfiber void size Ra of the nonwoven fabric layer (A) described later can be effectively reduced, and a suitable capillary force can be obtained. Further, Da is preferably 2.0 ⁇ m or more. By setting Da to 2.0 ⁇ m or more, it is possible to prevent the interfiber space size Ra of the nonwoven fabric layer (A) from becoming extremely small and to prevent the liquid permeability from deteriorating.
• the interfiber void size Ra calculated by the following formula (1) is 200 ⁇ m or less in the nonwoven fabric layer (A).
• Ra (100 x Ta x da) / (Wa x Da) -Da ... Equation (1) here, Ta: Thickness ( ⁇ m) of the non-woven fabric layer (A) da: Fineness (dtex) of the thermoplastic resin fiber constituting the non-woven fabric layer (A) Wa: Non-woven fabric layer (A) with a deemed basis weight (g / m 2 ) Da: The average single fiber diameter ( ⁇ m) of the thermoplastic resin fibers constituting the nonwoven fabric layer (A).
• each non-woven fabric layer is obtained as follows.
• Step 1 Add the average single fiber diameters obtained in the "Procedure for measuring the average single fiber diameter of the non-woven fabric layer" of each of the non-woven fabric layer whose thickness is to be measured and the other non-woven fabric layers to be laminated, and divide by two. Calculate the average value of the fiber diameters of the two layers.
• the average single fiber diameter is added and divided by 2 in the same manner with the other non-woven fabric layer. Calculate the average value of the fiber diameters of.
• Step 2 y is calculated in step 1 in the section of the laminated interface between the non-woven fabric layer whose thickness is to be measured and the other non-woven fabric layer to be laminated on the graph obtained in step 6 of "Procedure for specifying the laminated interface".
• the x-coordinate that takes the average value of the fiber diameters of the two layers is specified.
• Step 3 When other non-woven fabric layers are laminated on both sides of the non-woven fabric layer whose thickness is to be measured, the distance between the x-coordinates, which is the average value of the fiber diameters of the two layers to be laminated in the section of the laminated interface on both sides, is calculated. Calculated and used as the thickness of the non-woven fabric layer to be measured.
• the x-coordinate that takes the average value of the fiber diameters of the two layers in the section of the laminated interface and the non-woven fabric layer to be measured The distance from the x-coordinate of the exposed surface on one side is calculated and used as the thickness of the nonwoven fabric layer to be measured.
• the thickness Tt of the laminated nonwoven fabric can be obtained by calculating the distance between the x-coordinates of the surfaces on both sides of the laminated nonwoven fabric in step 3 of the "procedure for measuring the thickness of the nonwoven fabric layer".
• the fineness of the thermoplastic resin fibers constituting the nonwoven fabric layer is determined by using the average single fiber diameter of the thermoplastic resin fibers and the density of the thermoplastic resin fibers measured in "Procedure for measuring the average single fiber diameter of the nonwoven fabric layer". The value calculated from the following formula is rounded off to the second digit.
• d ( ⁇ ⁇ ⁇ ⁇ D 2 ) / 400
• d Fineness (dtex) of the thermoplastic resin fiber constituting the non-woven fabric layer
• ⁇ Density of thermoplastic resin fibers constituting the non-woven fabric layer
• D The average single fiber diameter ( ⁇ m) of the thermoplastic resin fibers constituting the non-woven fabric layer.
• the density ⁇ of the thermoplastic resin fiber is measured based on "8.17.2 Density tube method" of JIS L1013: 2010 "Chemical fiber filament yarn test method”.
• a density gradient tube having an appropriately adjusted density range is prepared, and the fiber density (g / cm 3 ) is measured to the third decimal place for about 0.1 g of fiber pieces collected from the non-woven fabric layer.
• the arithmetic mean of the results obtained by performing the same operation on 5 different samples randomly collected from the non-woven fabric layer was calculated, and the value rounded to the third decimal place was the density ⁇ (g / cm) of the first thermoplastic fiber. 3 ).
• the deemed basis weight W (g / m 2 ) of the nonwoven fabric layer is obtained as follows.
• the basis weight Wt (g / m 2 ) of the laminated nonwoven fabric is measured based on "6.2 Mass per unit area" of JIS L1913: 2010 "General nonwoven fabric test method”. Specifically, three test pieces cut into a size of 20 cm ⁇ 25 cm from a laminated non-woven fabric are collected per 1 m of sample width, each mass (g) in the standard state is measured, and the average value is calculated per 1 m 2. The value obtained by rounding off the second decimal place of the mass is defined as the basis weight Wt (g / m 2 ) of the laminated non-woven fabric.
• the interfiber void size represented by the formula (1) is the length of one side of the void defined by the fibers when assuming a model in which the fibers contained in the nonwoven fabric layer are regularly arranged in a lattice pattern. It is a value shown. It is considered that the smaller the interfiber space size, the stronger the capillary force acts, and the stronger the force of sucking up water.
• the interfiber void size Ra of the nonwoven fabric layer (A) having the smallest average single fiber diameter is set to 200 ⁇ m or less, preferably 100 ⁇ m or less, more preferably 80 ⁇ m or less, so that the outermost surface of the laminated nonwoven fabric is formed.
• the capillary force of the non-woven fabric layer (A) can be increased, and a large amount of the liquid can be transferred to the non-woven fabric layer (A) to exhibit good quick-drying property.
• the interfiber void size Ra is 30 ⁇ m or more in order to secure constant liquid permeability and water absorption.
• the interfiber void size Ra can be controlled by controlling the average single fiber diameter Da of the thermoplastic resin fibers constituting the non-woven fabric layer.
• the thickness of the nonwoven fabric layer (A) is preferably 100 ⁇ m or more. By setting the thickness of the nonwoven fabric layer (A) to 100 ⁇ m or more, more preferably 120 ⁇ m or more, more liquid absorbed by the laminated nonwoven fabric is retained by the nonwoven fabric layer (A), which will be described later on the surface on the nonwoven fabric layer (A) side.
• the water distribution ratio can be increased.
• the thickness of the nonwoven fabric layer (A) is preferably 1000 ⁇ m or less. By setting the thickness of the nonwoven fabric layer (A) to 1000 ⁇ m or less, it is possible to prevent the liquid from staying inside the nonwoven fabric layer (A) and suppressing the liquid transfer between the nonwoven fabric layers.
• Nonwoven fabric layer (B) The nonwoven fabric layer (B) in the laminated stretchable nonwoven fabric of the present invention is defined as a nonwoven fabric layer that is laminated in contact with the nonwoven fabric layer (A).
• the laminated nonwoven fabric of the present invention corresponds to at least one of the nonwoven fabric layers (B) laminated in contact with the nonwoven fabric layer (A) (when the nonwoven fabric layer (B) is in contact with only one of the nonwoven fabric layers (A) and laminated.
• the ratio Rb / Ra of the interfiber void size Rb ( ⁇ m) calculated by the following formula (2) to Ra ( ⁇ m) is 1.1 times or more. It is preferable to have.
• Rb (100 ⁇ Tb ⁇ db) / (Wb ⁇ Db) -Db ...
• Tb Thickness ( ⁇ m) of the non-woven fabric layer (B)
• db Fineness (dtex) of the thermoplastic resin fiber constituting the non-woven fabric layer (B).
• Wb Non-woven fabric layer (B) with a deemed basis weight (g / m 2 )
• Db The average single fiber diameter ( ⁇ m) of the thermoplastic resin fibers constituting the nonwoven fabric layer (B).
• the method for obtaining Tb ( ⁇ m), db (dtex), Wb (g / m 2 ), and Db ( ⁇ m) according to the formula (2) is the above-mentioned thickness T of the nonwoven fabric layer and the thermoplasticity constituting the nonwoven fabric layer.
• the fineness d of the resin fiber, the deemed grain W of the nonwoven fabric layer, and the average single fiber diameter D of the thermoplastic resin fibers constituting the nonwoven fabric layer are as shown.
• Rb / Ra By setting Rb / Ra to 1.1 times or more, more preferably 1.2 times or more, still more preferably 1.5 times or more, a large difference in capillary force between the nonwoven fabric layer (A) and the nonwoven fabric layer (B). Therefore, the moisture can be efficiently transferred to the non-woven fabric layer (A), and the quick-drying property can be improved.
• the ratio of Rb to Ra increases, the ratio of interfiber voids in the nonwoven fabric layer (B) naturally increases.
• the Rb / Ra is preferably 10.0 times or less from the viewpoint of suppressing the uneven basis weight generated at that time and suppressing the decrease in strength starting from this uneven basis weight.
• the interfiber void size Rb of the nonwoven fabric layer (B) is preferably 100 ⁇ m or more. By setting Rb to 100 ⁇ m or more, more preferably 120 ⁇ m or more, the liquid permeability is improved, so that the amount of liquid remaining in the nonwoven fabric layer (B) is reduced, and quick-drying can be obtained.
• the interfiber void size Rb of the nonwoven fabric layer (B) is preferably 500 ⁇ m or less. By setting Rb to 500 ⁇ m or less, it is possible to prevent the liquid transferred to the nonwoven fabric layer (A) from seeping out when a load is applied to the laminated nonwoven fabric, and to maintain a dry surface.
• the average single fiber diameter Db of the thermoplastic resin fibers constituting the nonwoven fabric layer (B) is 15.0 ⁇ m to 30.0 ⁇ m. It is preferably within the range of.
• the thickness of the nonwoven fabric layer (B) is preferably in the range of 100 to 1000 ⁇ m.
• the thickness of the nonwoven fabric layer (B) is preferably in the range of 100 to 1000 ⁇ m.
• the laminated non-woven fabric of the present invention has four surfaces, an absorption surface which is the surface on which the physiological saline is absorbed and a surface on the opposite side thereof, when the physiological saline is absorbed on each of the surfaces on both sides thereof by the following procedure.
• the water distribution ratio defined by the following formula (3) is preferably 40% or less on at least one surface.
• Step 1 Cut out a 5 cm x 5 cm sample from the laminated non-woven fabric.
• Procedure 2 Prepare two pieces of filter paper conforming to JIS P3801 cut into 5 cm x 5 cm for each measurement, and measure the mass of each.
• Procedure 3 Drop 0.250 ⁇ 0.005 mL of physiological saline onto a polypropylene film. At this time, the mass of the saline solution to be dropped is measured.
• Procedure 4 Place the laminated non-woven fabric on the dropped saline solution with the absorption surface facing down to absorb it, and hold it for 1 minute.
• Step 5 After holding the procedure 4, the laminated non-woven fabric is removed from the polypropylene film, placed on the first sheet of the filter paper with the absorption surface facing up, and the second sheet of the filter paper is quickly placed on the first sheet of the filter paper. Put on.
• Step 6 Place a 125 g weight on the second filter paper so that the pressure is 5 g / cm 2, and hold it for 1 minute.
• Procedure 7 After holding the procedure 6, the weight is removed, the mass of each filter paper is measured, and the mass increase of each filter paper is calculated.
• W0 Mass (g) of the physiological saline solution dropped in the above procedure 3
• W1 The mass increase (g) of the filter paper applied to the surface in the above procedure 7.
• the water distribution ratio required by this procedure indicates that the lower the value, the smaller the amount of liquid retained on the surface. That is, if this water distribution ratio is low on the surface that hits the skin surface, a dry feeling can be felt when touched even after the liquid is absorbed.
• the water distribution ratio is 40% or less, more preferably 30% or less, still more preferably 20% or less on at least one surface of the above-mentioned four surfaces to maintain the surface. It has a low water content and can effectively maintain a dry surface.
• the nonwoven fabric layer (B) is laminated on at least one of the outermost surfaces. That is, as described above, the nonwoven fabric layer (B) is defined as the nonwoven fabric layer that is laminated in contact with the nonwoven fabric layer (A). Non-woven fabric layer (B) / Non-woven fabric layer (A) ... It has a laminated structure. As described above, the nonwoven fabric layer (A) is defined as having the smallest average single fiber diameter among the nonwoven fabric layers constituting the laminated nonwoven fabric, so that the nonwoven fabric layer (B) side having a relatively large average single fiber diameter is used.
• the liquid When the liquid is absorbed from the outermost surface, the liquid is rapidly transferred to the non-woven fabric layer (A) whose interfiber void size is controlled to be very small as described above, so that the liquid is most quickly transferred to the non-woven fabric layer (B) side.
• the water distribution ratio on the surface is reduced, and quick-drying can be obtained.
• the water distribution ratio on the surface opposite to the surface where the water distribution ratio is 40% or less is 50% or more.
• the water distribution ratio is smoothly transferred from the surface on which the liquid is absorbed to the other surface without retaining the absorbed liquid inside the laminated non-woven fabric. Can be made to.
• the nonwoven fabric layer (A) having high capillary force is arranged on one surface. Is preferable.
• the laminated nonwoven fabric of the present invention preferably has a water absorption rate of 20 seconds or less as measured from at least one surface.
• the water absorption rate referred to here is measured based on "7.1.1 Drop method” of JIS L1907: 2010 "Water absorption test method for textile products”. Drop one drop of water on the laminated non-woven fabric, measure the time until it is absorbed and the specular reflection on the surface disappears, calculate the simple average of the values measured at 10 different points, and use the second as the unit. The value rounded off to the first place is taken as the water absorption rate in the present invention.
• a water absorption rate of 20 seconds or less, more preferably 10 seconds or less, indicates that the performance of removing water adhering to the surface is good.
• the basis weight of the laminated nonwoven fabric of the present invention is preferably 10 to 100 g / m 2.
• a laminated nonwoven fabric having mechanical strength that can be put into practical use can be obtained.
• a laminated nonwoven fabric having appropriate flexibility suitable for use as a nonwoven fabric for sanitary materials can be obtained.
• each nonwoven fabric layer is integrated.
• integrated means that the nonwoven fabric layers are joined by entanglement of fibers, fixation by components such as an adhesive, and fusion of thermoplastic resins constituting the respective layers.
• the laminated nonwoven fabric of the present invention may be provided with a hydrophilic agent for the purpose of increasing water absorption.
• the sanitary material of the present invention has excellent water absorption and quick-drying property because at least a part thereof is composed of the laminated nonwoven fabric of the present invention.
• the sanitary material of the present invention can be suitably used for health-related purposes such as medical treatment and long-term care.
• the sanitary material of the present invention can be preferably used mainly for disposable articles, and examples thereof include disposable diapers, sanitary napkins, gauze, bandages, masks, gloves, and adhesive plasters.
• disposable diapers can be used as constituent members of various parts such as top sheets, back seats, and side gathers.
• the diaper as a sanitary material of the present invention preferably has a top sheet made of the laminated non-woven fabric of the present invention.
• the laminated non-woven fabric of the present invention is used as the top sheet of a diaper, if the non-woven fabric layer (B) is used so as to be installed on the skin surface side of the top sheet, the excreted urine is quickly absorbed into the non-woven fabric layer (A). Since it can be transferred quickly, the surface of the top sheet can be kept dry.
• the waist portion of the diaper as a sanitary material of the present invention is made of the laminated nonwoven fabric of the present invention.
• the laminated nonwoven fabric of the present invention is used as a part of the waist portion of the diaper, when the nonwoven fabric layer (B) is used so as to be installed on the skin surface side of the waist portion of the diaper, sweat is quickly absorbed and the nonwoven fabric layer (A) is used. ), So the surface of the waist can be kept dry.
• the sanitary material of the present invention can also be suitably used as a mask.
• the inner surface layer thereof is composed of the laminated nonwoven fabric of the present invention.
• the inner surface layer in the present invention refers to the layer installed on the most oral side among the surface bodies covering the mouth.
• the method for producing the nonwoven fabric layer (A) and the nonwoven fabric layer (B) constituting the laminated nonwoven fabric of the present invention can be selected from known manufacturing methods such as the spunbond method, the melt blow method, and the short fiber card method.
• the spunbond method is cited as a preferable method because it is excellent in productivity.
• the spunbond method is a method in which a thermoplastic resin, which is a raw material, is melted, spun from a spinneret, and then cooled and solidified. The resulting yarn is pulled by an ejector, stretched, and collected on a moving net.
• This is a method for producing a non-woven fabric, which requires a step of thermally adhering the non-woven fiber into a web.
• the shape of the spinneret and ejector used various shapes such as a round shape and a rectangular shape can be adopted. Above all, from the viewpoint that the amount of compressed air used is relatively small and the yarns are less likely to be fused or scratched, it is preferable to use a combination of a rectangular base and a rectangular ejector.
• the spinning temperature is preferably (melting temperature of the raw material thermoplastic resin + 10 ° C.) or more (melting temperature of the raw material thermoplastic resin + 100 ° C.) or less.
• the melt viscosity of the polymer used for the nonwoven fabric layer (A) is preferably 100 Pa ⁇ s or less, and more preferably 50 Pa ⁇ s or less.
• the melt viscosity of the polymer referred to here is when the chip-shaped polymer is measured by a vacuum dryer with a moisture content of 200 ppm or less, the strain rate is changed stepwise, and the measurement temperature is the same as the spinning temperature. It is a value at a strain rate of 1216s -1.
• the spun yarn is cooled next, but as a method of cooling the spun yarn, for example, a method of forcibly blowing cold air onto the yarn, or natural cooling at the ambient temperature around the yarn.
• a method of adjusting the distance between the spinneret and the ejector, and the like, or a method of combining these methods can be adopted.
• the cooling conditions can be appropriately adjusted and adopted in consideration of the discharge amount per single hole of the spinneret, the spinning temperature, the atmospheric temperature and the like.
• the cooled and solidified yarn is pulled and stretched by the compressed air ejected from the ejector.
• the average interfiber void size of the nonwoven fabric layer (A) and the nonwoven fabric layer (B) can be controlled by the diameter of the constituent fibers.
• the diameter of the fiber is determined by the discharge amount and the traction speed per the discharge hole of the spinneret, that is, the spinning speed. Therefore, it is preferable to determine the discharge amount and the spinning speed so that the desired interfiber void size can be controlled to a diameter that can be obtained.
• the spinning speed is preferably 2000 m / min or more.
• the spinning speed is preferably 2000 m / min or more.
• the long fiber yarns stretched by traction in this way are collected by a moving net to form a sheet, and then subjected to a process of heat bonding.
• the laminated non-woven fabric of the present invention is made by laminating a non-woven fabric layer.
• a method of laminating the non-woven fabric layer for example, the thermoplastic resin fiber is captured by the spunbond method on the nonwoven fabric layer obtained by collecting the thermoplastic resin fiber on the collection net by the spunbond method as described above.
• Two or more non-woven fabric layers obtained separately are superposed offline and laminated and integrated by thermal pressure bonding or the like.
• a method or the like can be adopted. Above all, since it is excellent in productivity, a method of continuously collecting the next nonwoven fabric layer in-line on the nonwoven fabric layer and laminating and integrating them by thermal adhesion is preferable.
• a thermal embossed roll in which a pair of upper and lower roll surfaces are engraved (concavo-convex portions), and one roll surface is flat (smooth).
• Heat embossed roll consisting of a combination of a roll with engraving (unevenness) on the surface of the other roll, and a thermal calendar roll consisting of a pair of upper and lower flat (smooth) rolls. It is possible to adopt a method of bonding or a method of thermocompression bonding such as ultrasonic bonding in which heat is welded by ultrasonic vibration of a horn.
• a so-called air-through method which is a method of blowing hot air, can also be mentioned.
• the method of thermally adhering with a pair of upper and lower thermal rolls is preferable because the nonwoven fabric layer (A) can be densified and the interfiber void size can be reduced by adhering the laminated nonwoven fabric layer while compressing it.
• the linear pressure received by the laminated nonwoven fabric between the rolls is 100 N / cm or more so that the nonwoven fabric layer (A) can be sufficiently densified. Therefore, it is preferable.
• the nonwoven fabric layer (B) is less likely to be compressed with respect to the nonwoven fabric layer (A), so that the difference in the void size between the fibers of the nonwoven fabric layer (A) and the nonwoven fabric layer (B) is reached. Can be secured greatly.
• a hydrophilic agent may be added to the laminated nonwoven fabric of the present invention before winding.
• Examples of the method for applying the hydrophilizing agent to the laminated nonwoven fabric include coating with kiss roll or spray, dip coating, etc., but coating with kiss roll is preferable from the viewpoint of uniformity and ease of controlling the amount of adhesion.
• the present invention will be described in detail based on examples. However, the present invention is not limited to these examples.
• the one without any special description is the one obtained by the measurement based on the above-mentioned method.
• the laminated interface of the laminated nonwoven fabric was specified by the above-mentioned "procedure for specifying the laminated interface".
• a high-resolution three-dimensional X-ray microscope "nano3DX” manufactured by Rigaku Co., Ltd. was used. The resolution was 0.6 ⁇ m / voxel.
• Thickness by a simple method An image was taken of the cross section of the laminated non-woven fabric perpendicular to the mechanical direction at a magnification at which the thickness can be observed with a scanning electron microscope (“S-5500” manufactured by Hitachi High-Technologies Corporation). The thickness of the laminated non-woven fabric and each non-woven fabric layer was measured based on the captured image.
• Interfiber void size The interfiber void size of the nonwoven fabric layer was calculated by the following equation.
• R (100 ⁇ T ⁇ d) / (W ⁇ D) -D here, T: Thickness of the non-woven fabric layer ( ⁇ m). It is measured by the above (4).
• d Fineness (dtex) of the thermoplastic resin fiber constituting the non-woven fabric layer. It is measured according to the definition of d described above.
• W Non-woven fabric layer with a deemed basis weight (g / m 2 ). Measured according to the definition of W above. In this example and comparative example, it was confirmed that there was no difference from the basis weight of the non-woven fiber web layer described later.
• D The average single fiber diameter ( ⁇ m) of the thermoplastic resin fibers constituting the non-woven fabric layer. It is measured by the above (2).
• Example 1 (Non-woven fiber web layer (A)) Polypropylene (PP, melt viscosity 30 Pa ⁇ s) was melted by an extruder and spun from a rectangular mouthpiece at a single hole discharge rate of 0.30 g / min. After the spun yarn is cooled and solidified, it is pulled and stretched by compressed air with an ejector pressure of 0.10 MPa in a rectangular ejector, collected on a moving net, and non-woven fiber by the spunbond method. A web layer (A) was obtained. The fibers constituting the obtained non-woven fiber web layer (A) had an average single fiber diameter of 10.6 ⁇ m. The basis weight was 35.0 g / m 2 .
• Non-woven fiber web layer (B) Polypropylene (PP), which is the same as the raw material used for the non-woven fiber web layer (A), was melted by an extruder and spun from a rectangular mouthpiece at a single-hole discharge rate of 0.85 g / min. After the spun yarn is cooled and solidified, it is pulled and stretched by compressed air having a pressure at the ejector of 0.08 MPa in a rectangular ejector, and is captured on the non-woven fiber web layer (A) on the moving net. The non-woven fiber web layer (B) was obtained by the spunbond method. The fibers constituting the obtained non-woven fiber web layer (B) had an average single fiber diameter of 20.4 ⁇ m. The basis weight was 30.0 g / m 2 .
• the non-woven fiber web layer (B) By collecting the non-woven fiber web layer (B) on the non-woven fiber web layer (A) and laminating it in-line, the non-woven fiber web layer (A) / the non-woven fiber web layer (B) 2 A layered laminated fiber web was obtained.
• the upper and lower rolls of the obtained laminated fiber web are made of metal embossed rolls in which regular circular protrusions are staggered at the same pitch in both directions of MD and CD on the upper roll, and the metal flat roll is used as the lower roll.
• heat bonding was performed at a linear pressure of 300 N / cm and a heat bonding temperature of 125 ° C.
• hydrophilic treatment was performed to obtain a laminated nonwoven fabric having a basis weight of 65.0 g / m 2.
• the obtained laminated non-woven fabric was evaluated for the thickness of each layer, the size of the voids between fibers, the water distribution ratio, the water absorption rate, and the water absorption and quick-drying property.
• the thickness of the nonwoven fabric layer (A) was 300 ⁇ m, and the interfiber void size was 54 ⁇ m.
• the thickness of the nonwoven fabric layer (B) was 420 ⁇ m, and the interfiber void size was 181 ⁇ m.
• Table 1 The results are shown in Table 1.
• Example 2 Except that the single-hole discharge rate was 0.80 g / min in the step of obtaining the non-woven fiber web layer (A) and the single-hole discharge rate was 1.20 g / min in the step of obtaining the non-woven fiber web layer (B).
• a laminated nonwoven fabric was obtained in the same manner as in Example 1. Table 1 shows the evaluation results of the obtained laminated nonwoven fabric.
• Example 3 A laminated nonwoven fabric was obtained in the same manner as in Example 1 except that the single-hole discharge rate was 0.35 g / min in the step of obtaining the non-woven fiber web layer (B). Table 1 shows the evaluation results of the obtained laminated nonwoven fabric.
• Example 4 The laminated nonwoven fabric was prepared in the same manner as in Example 1 except that the basis weight of the non-woven fiber web layer (A) was 15.0 g / m 2 and the basis weight of the non-woven fiber web layer (B) was 13.0 g / m 2. Obtained. Table 1 shows the evaluation results of the obtained laminated nonwoven fabric.
• Example 5 A laminated nonwoven fabric was obtained in the same manner as in Example 1 except that the basis weight of the non-woven fiber web layer (A) was 10.0 g / m 2. Table 1 shows the evaluation results of the obtained laminated nonwoven fabric.
• Example 6 (Non-woven fiber web layer (A)) A non-woven fiber web layer (A) was obtained in the same manner as in Example 1.
• Non-woven fiber web layer (B) A non-woven fiber web layer (B) was obtained in the same manner as in Example 1 except that the towed and stretched yarns were directly collected on the moving net.
• the non-woven fiber web layer (A) and the non-woven fiber web layer (B) are laminated offline, and have a two-layer structure of the non-woven fiber web layer (A) and the non-woven fiber web layer (B). Obtained a laminated fiber web.
• laminated non-woven fabric The obtained laminated fiber web was heat-bonded in the same manner as in Example 1 and subjected to hydrophilic treatment to obtain a laminated nonwoven fabric. Table 1 shows the evaluation results of the obtained laminated nonwoven fabric.
• Example 7 The polymer used for the nonwoven fabric layer (A) and the nonwoven fabric layer (B) was polyethylene glycol copolymerized polyethylene terephthalate (copolymerized PET, the copolymerization rate of polyethylene glycol is 8% by mass of the polymer).
• Non-woven fiber web layer (A) As the raw material polymer of the fiber, copolymerized polyethylene terephthalate (copolymerized PET) obtained by copolymerizing polyethylene glycol with 8% by mass of the polymer was used. A non-woven fiber web layer (A) was obtained in the same manner as in Example 1 except that the traveling speed of the net was changed by using the copolymerized PET. The fibers constituting the obtained spunbonded nonwoven fabric layer (A) had an average single fiber diameter of 8.5 ⁇ m. The basis weight was 30.0 g / m 2 .
• Non-woven fiber web layer (B) The non-woven fiber web layer (B) was obtained in the same manner as in Example 1 except that the same copolymerized PET as the raw material used for the non-woven fiber web layer (A) was used.
• the characteristics of the fibers constituting the obtained spunbonded nonwoven fabric layer (B) were that the average single fiber diameter was 17.5 ⁇ m.
• the basis weight was 30.0 g / m 2 and 37.0 g / m 2 .
• laminated non-woven fabric A laminated nonwoven fabric was obtained by the same method as in Example 1 except that the heat bonding temperature was set to 200 ° C.
• the thickness of the nonwoven fabric layer (A) was 270 ⁇ m, and the interfiber void size was 73 ⁇ m.
• the thickness of the nonwoven fabric layer (B) was 350 ⁇ m, and the interfiber void size was 158 ⁇ m. Table 1 shows the evaluation results of the obtained laminated nonwoven fabric.
• the single-hole discharge amount was 1.20 g / min in the step of obtaining the non-woven fiber web layer (A), the pressure at the ejector was 0.08 MPa, and the single-hole discharge amount was set in the step of obtaining the non-woven fiber web layer (B).
• a laminated nonwoven fabric was obtained in the same manner as in Example 1 except that the pressure was 1.20 g / min.
• the fibers constituting the obtained non-woven fiber web layer (A) had an average single fiber diameter of 22.0 ⁇ m.
• the thickness of the nonwoven fabric layer (A) was 430 ⁇ m, and the interfiber void size was 245 ⁇ m. Table 1 shows the evaluation results of the obtained laminated nonwoven fabric.
• Examples 1 to 7 are excellent in water absorption and quick drying.
• both the water absorption rate and the water absorption and quick-drying property were compatible at a high level.
• Comparative Example 1 the result was that the water absorption and quick-drying property were low.

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