Pulp composite nonwoven fabric product and production method of the same

Abstract

To provide a pulp composite nonwoven fabric product which does not use a material derived from petroleum, matches requirement of enhanced sustainable consciousness, has less lint generation, and a production method of the same.SOLUTION: There is provided a pulp composite nonwoven fabric product formed by water flow interlacing of pulp fibers and cellulose fibers being different from the pulp fibers, the pulp composite nonwoven fabric having a basis weight of 30 to 90 g / m2, and having irregularities formed by water flow interlacing on the front and rear surfaces thereof.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a pulp composite nonwoven fabric product and a method for producing the same. [Background technology]

[0002] Pulp composite nonwoven fabric products in which pulp fibers are integrated with other fibers are known. Among conventional pulp composite nonwoven fabric products, for example, products for wipes are made by integrating hydrophilic pulp fibers with synthetic fibers derived from petroleum, such as high-strength polypropylene, into a sheet shape, and thus achieve both water and oil absorbency and strength. These pulp composite nonwoven fabric wipes are highly versatile due to their compatibility with liquid absorbency and strength, and are used for various purposes such as cleaning production lines, kitchen counters, machines, filling machines, and facilities, wiping off dirt, and wiping hands at cooking and manufacturing sites (Patent Document 1, Patent Document 2, etc. below).

[0003] As a specific example of a conventional pulp composite nonwoven fabric wipe, for example, Patent Document 1 below discloses a pulp composite nonwoven fabric wipe in which pulp fibers and a spunbond nonwoven fabric of synthetic fibers such as polypropylene are integrated together. Patent Document 2 discloses a pulp composite nonwoven fabric wipe in which a web containing pulp fibers, recycled fibers, and composite synthetic fibers is integrated with a spunbond nonwoven fabric of synthetic fibers such as polypropylene by hydroentanglement. The pulp composite nonwoven fabric wipes disclosed in Patent Documents 1 and 2, which are made by integrating pulp fibers with a synthetic resin spunbond nonwoven fabric, have sufficiently high liquid absorbency and strength, particularly when wet.

[0004] On the other hand, in recent years, the problem of marine pollution caused by microplastics has attracted attention, and there has been a global movement to reduce or eliminate the use of plastic in various products due to environmental considerations, etc. In response to this trend, conventional pulp composite nonwoven wipes contain 20% or more petroleum-derived synthetic fibers, and it is desirable to reduce the amount of petroleum-derived synthetic resins used in such pulp composite nonwoven wipes for environmental reasons. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-084385 A [Patent Document 2] JP 2019-039116 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, simply decreasing the blending ratio of synthetic fibers and increasing the blending ratio of pulp fibers tends to decrease the strength and also makes it easier for some of the pulp fibers to come off from the surface as lint.

[0007] In these pulp composite nonwoven products, there are technologies that can increase strength and reduce lint by applying binders and adhesives, but the use of binders and adhesives goes against the growing awareness of sustainability. Furthermore, the application of a binder, etc., tends to reduce the liquid absorption property, resulting in increased costs.

[0008] Therefore, the main object of the present invention is to provide a pulp composite nonwoven fabric product and a manufacturing method thereof that does not use petroleum-derived materials, meets the demands of growing sustainability awareness, and produces little lint. [Means for solving the problem]

[0009] The means for solving the problems of the present invention are as follows. (First aspect) A pulp composite nonwoven fabric product in which pulp fibers and cellulose fibers different from the pulp fibers are hydroentangled, Basis weight: 30~90g / m 2 and At least one of the front and back surfaces has projections and recesses formed by hydroentanglement. A pulp composite nonwoven fabric product.

[0010] The pulp composite nonwoven fabric product of the present invention does not use petroleum-derived materials and meets the demands of growing awareness of sustainability. By hydroentangling the pulp fibers and the cellulose fibers in such a manner that irregularities are formed on at least one of the front and back surfaces at the product stage, a product with less lint can be obtained.

[0011] (Second aspect) A method for producing a pulp composite nonwoven fabric product in which pulp fibers and cellulose fibers different from the pulp fibers are hydroentangled, comprising: The order of line direction is: laminating the pulp fiber layer on the cellulose fiber layer; a step of spraying a water flow from above the pulp fiber layer toward the laminate of fiber layers to hydroentangle the fibers; A drying step of drying the moisture, Forming unevenness by hydroentanglement on at least one of the front and back surfaces of the product without mechanical embossing. A method for producing a pulp composite nonwoven fabric product comprising the steps of:

[0012] According to the second aspect, a product with less lint can be obtained. Effect of the Invention

[0013] According to the present invention, it is possible to provide a pulp composite nonwoven fabric product and a manufacturing method thereof that do not use petroleum-derived materials, meet the demands of growing sustainability awareness, and produce little lint. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a plan view illustrating the unevenness of a pulp composite nonwoven fabric product according to an embodiment. [Figure 2A] FIG. 2 is an enlarged view of a portion of FIG. [Figure 2B] FIG. 2B corresponds to FIG. 2A and is an enlarged view of a portion of a support used in a manufacturing example. [Diagram 3] 13 is a plan view of another example of a concave-convex shape. [Figure 4A] FIG. 2 is a schematic explanatory diagram of an example of a concave-convex shape. [Figure 4B] 4B is an explanatory diagram showing another example of projections and recesses in a pulp composite nonwoven fabric product according to an embodiment of the present invention, in a cross-sectional view taken along line 4B-4B in FIG. 2. [Diagram 5] FIG. 1 is an explanatory diagram showing an outline of a first example of a method for producing a pulp composite nonwoven fabric product according to an embodiment. [Figure 6] FIG. 4 is an explanatory diagram showing an outline of a second example of a method for producing a pulp composite nonwoven fabric product according to an embodiment. [Figure 7] FIG. 4 is an explanatory diagram showing an outline of a third example of a method for producing a pulp composite nonwoven fabric product according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Next, the embodiments of the present invention will be described in detail below, but the present invention is not limited to these embodiments.

[0016] The pulp composite nonwoven fabric product of the embodiment includes a sheet form, a sheet wound into a roll, and further, a product that has been cut to size with perforations or cut to a specified size for commercial or household use.

[0017] The pulp composite nonwoven fabric product of the embodiment can be used for various purposes such as wiping, cleaning production lines for various items, countertops, machinery, filling machines, facilities, wiping off dirt, and wiping hands in cooking and production sites. It is also suitable for wiping objects, wiping living bodies such as the human body, wiping off dirt and liquids, etc. Furthermore, since it has excellent water absorption, liquid absorption, oil absorption and heat resistance, it is also suitable for cooking applications (wrapping food, removing moisture from food, absorbing oil for fried food, etc.). In these applications, the fact that the product does not use petroleum-derived materials meets the demands of growing sustainability awareness and produces little lint further enhances the product's value.

[0018] <First embodiment> According to a first embodiment, there is provided a pulp composite nonwoven fabric product in which pulp fibers and cellulose fibers different from the pulp fibers are hydroentangled, Basis weight: 30~90g / m 2 and The surface and back are unevenly woven by water flow. The resulting pulp composite nonwoven fabric product is characterized by the above-mentioned.

[0019] The basis weight of the pulp composite nonwoven fabric in which the pulp fiber of the embodiment and a cellulose fiber different from the pulp fiber (hereinafter, unless otherwise specified, will be referred to as "cellulose fiber". The term "cellulose fiber" does not include semi-synthetic fibers such as acetate, and means fibers derived from natural products) are entangled is 30 to 90 g / m. 2 , preferably 40 to 80 g / m 2 , more preferably 45 to 60 g / m 2 If the basis weight is within the appropriate range, in combination with other configurations of the present invention, it is possible to obtain the liquid absorbency and strength required for general-purpose use. The basis weight is measured based on JIS P 8124.

[0020] The thickness of the pulp composite nonwoven fabric product is not necessarily limited, but is preferably 350 to 1050 μm, and more preferably 450 to 900 μm. Note that this thickness refers to a value measured based on JIS L 1913.

[0021] The total ratio of pulp fibers and cellulose fibers in the constituent fibers of the pulp composite nonwoven fabric product of this embodiment is 95% or more, and preferably 100%. Since pulp fibers and cellulose fibers are derived from natural products, if the total proportion of pulp fibers and cellulose fibers is 95% or more, it can be said that the product has sufficiently reduced plastic content compared to conventional pulp composite nonwoven products. Also, if it is 100%, it can be said to be plastic-free. If it contains fibers other than pulp fibers and cellulose fibers, it is preferable that the fibers are natural fibers, such as semi-synthetic fibers such as acetate, from the perspective of plastic-free. However, even if it contains synthetic fibers at 5% or less, the effect of plastic reduction can be fully achieved.

[0022] Furthermore, pulp fibers and cellulose fibers derived from wood have excellent heat resistance. The melting points of the polyethylene and polypropylene fibers used in many conventional pulp composite nonwoven products are below 170 degrees Celsius. As a result, some conventional pulp composite nonwoven products are not particularly suitable for wiping off high-temperature oil, absorbing oil, or filtering oil. In the pulp composite nonwoven fabric of this embodiment, when the fibers are 100% pulp fibers and cellulose fibers, the heat resistance temperature can be increased to 400 degrees or higher. Therefore, the pulp composite nonwoven fabric product can be used, for example, in food factories, by manufacturers of boxed lunches and prepared foods, and in homes as cooking paper and sheets for thickening oil.

[0023] On the other hand, cellulose fibers include regenerated cellulose fibers and rayon obtained by the viscose method. The blending ratio of rayon in the cellulose fibers is not necessarily limited, but it is preferably less than 50% by mass, particularly 45 to 20% by mass, in order to enrich the pulp fiber content. Rayon is a regenerated cellulose fiber made from wood, not petroleum-based materials like nylon, polypropylene, and polyester.

[0024] The use of cellulose fibers makes it possible to provide a product with excellent water absorption, oil absorption, and water absorption speed, expanding the range of uses, particularly for wiping off liquids such as water and oil.

[0025] In an embodiment, the cellulose fiber may be a fiber derived from a natural product selected from the group consisting of natural fibers derived from plants, rayon, polynosic, cupra, Tencel (registered trademark), lyocell, and cellulose fibers obtained by melt spinning. Examples of natural fibers derived from plants other than wood pulp fibers include natural fibers derived from plants such as cotton, flax, flax, ramie, jute, banana, bamboo, kenaf, shell ginger, hemp, and kapok.

[0026] The regenerated cellulose fibers as cellulose fibers in the embodiments are regenerated fibers made by dissolving cellulose raw materials and then regenerating them into a fibrous form, and examples of such regenerated fibers include rayon and polynosic obtained by the viscose process, cupra obtained by the cuprammonium process, and solvent-spun cellulose fibers such as Tencel (registered trademark) and Lyocell obtained by the solvent spinning process, as well as other regenerated fibers.

[0027] Among regenerated cellulose fibers, lyocell is particularly preferred. Lyocell is a regenerated cellulose fiber produced by a solvent spinning method using wood as a raw material. Lyocell is also sometimes called Tencel.

[0028] When lyocell is contained, it is preferable that the content is less than 50% by mass, and particularly 45 to 20% by mass. The inclusion of lyocell tends to increase the strength when wet. Therefore, by including lyocell, the cloth has excellent strength when dry and when wet, and the change in strength from dry to wet and from wet to dry is small. Therefore, the cloth is easy to use in situations where both wiping off dry objects and wiping off liquids are required, and in applications where the cloth is soaked in liquids such as water or liquid detergent and used for wiping.

[0029] The pulp fibers of the present embodiment can be selected from pulp fibers derived from broadleaf trees, pulp fibers derived from coniferous trees, and pulp fibers derived from waste paper. The average fiber length (hereinafter also referred to as the fiber length) is preferably 1.5 to 6.0 mm, particularly 2.5 to 5.0 mm. This average fiber length provides high hydroentanglement properties with lyocell.

[0030] Among the above pulp fibers, pulp fibers derived from coniferous trees are particularly preferred. The pulp fibers derived from coniferous trees have an average fiber length of 3.5 to 4.0 mm and a fiber diameter of about 50 μm, and are easily entangled with regenerated cellulose fibers, making it particularly difficult for lint derived from the pulp fibers to be generated. Specifically, they are bleached coniferous kraft pulp (NBKP) and unbleached coniferous pulp (NUKP). The pulp fibers preferably contain 95% by mass or more of the pulp fibers derived from coniferous trees. In particular, the pulp fibers preferably contain 100% by mass of pulp fibers derived from coniferous trees.

[0031] The blending ratio of pulp fiber to cellulose fiber in the pulp composite nonwoven fabric product of the present embodiment is not necessarily limited, but is preferably pulp fiber:cellulose fiber blending ratio = (20:80) to (80:20), and particularly preferably pulp fiber:cellulose fiber blending ratio = (50:50) to (80:20). When the blending ratio of pulp fiber to cellulose fiber is (50:50) to (80:20), the liquid absorption properties of the pulp fiber, the strength improvement of the cellulose fiber, and the suppression of lint generation are well balanced, and the flexibility and softness are also good, resulting in a pulp composite nonwoven fabric product with excellent versatility.

[0032] The fiber length of the cellulose fibers in the pulp composite nonwoven fabric product of this embodiment is preferably 21 mm to 78 mm, particularly preferably 28 mm to 65 mm. The cellulose fibers having a fiber length of 21 mm to 78 mm are suitably entangled with the pulp fibers, particularly the pulp fibers derived from conifers, by hydroentanglement. Therefore, the pulp composite nonwoven fabric product of this embodiment is less likely to generate lint. The fiber length according to the present invention is the length-weighted average fiber length L(l) measured on the defibrated fibers after defibration in accordance with JIS P 8220 using a fiber length measuring device (Kayani / Fiber Lab, manufactured by Metso Automation). When it is impossible or difficult to measure using this fiber length measuring device, the fiber can be observed under an electron microscope together with a nonwoven fabric whose fiber length is known based on the "dtex" information from the raw cotton production marker, and a comparison measurement can be made to determine the fiber length from the comparison results.

[0033] The fiber thickness of the cellulose fibers in the pulp composite nonwoven fabric product of this embodiment is not necessarily limited, but is preferably 0.8 dtex to 1.8 dtex, particularly preferably 1.0 dtex to 1.6 dtex. This fiber thickness tends to ensure strong entanglement with pulp fibers, particularly pulp fibers derived from coniferous trees. The fiber thickness can be calculated from the specific gravity of the fiber, the thickness measured by observation under an electron microscope as in the previous section, and the cross-sectional shape.

[0034] In the pulp composite nonwoven fabric product of this embodiment, unevenness is formed on the front and back surfaces by hydroentanglement, as will be described later.

[0035] <Second embodiment> A method for producing a pulp composite nonwoven fabric product in which pulp fibers and cellulose fibers different from the pulp fibers are hydroentangled, comprising: The order of line direction is: laminating the pulp fiber layer on the cellulose fiber layer; and spraying a water flow from above the pulp fiber layer toward the laminate of fiber layers to hydroentangle the fibers. Without mechanical embossing, the unevenness is created on the front and back surfaces of the product by hydroentanglement. A method for producing a pulp composite nonwoven fabric product comprising the steps of:

[0036] In this case, there is also provided a method for producing a pulp composite nonwoven fabric product, which includes a step of forming the cellulose fiber layer into a sheet and laminating the pulp fiber layer on the sheet of the cellulose fiber layer while continuously transporting the sheet in one direction.

[0037] An example of a method for producing a pulp composite nonwoven fabric product will be described with reference to the drawings. As shown in FIG. 4A, a water flow is sprayed from above the pulp fiber layer 10 toward the laminate 30 of the pulp fiber layer 10 and the cellulose fiber layer 20 to hydroentangle the pulp fibers and the cellulose fibers.

[0038] A water stream JW is sprayed toward the laminate 30 to hydroentangle the pulp fibers and cellulose fibers, thereby forming projections and recesses on the front and back surfaces of the product due to hydroentanglement, as shown in FIG. 4B. The formation of unevenness due to hydroentanglement generally occurs in a state in which water has evaporated after hydroentanglement.

[0039] The planar shape of the unevenness may be substantially circular as shown in Figures 1 and 2A, or may be a hexagon as shown in Figure 3. In the illustrated example, the planar shape of the unevenness is illustrated with clear edges, but unlike mechanical embossing, the unevenness is formed by an entanglement process using a high-energy water flow JW (see Figure 4A), and therefore the edges of the uneven shape are not necessarily clear in the actual product.

[0040] The planar shape of the projections and recesses is preferably a circle, an approximately circle, an ellipse, or an approximately ellipse. There is no limitation on the size, but in the case of a circle or an ellipse, the radius, the minor axis, and the major axis are preferably 2 to 5 mm. If necessary, the shape may be a triangle, a square, or another polygon.

[0041] In the pulp composite nonwoven fabric product of the embodiment, unevenness is formed on the front and back surfaces by hydroentanglement. The unevenness improves the wiping ability to scrape off dirt and increases softness. In particular, the unevenness caused by hydroentanglement is formed in the direction in which the sheet is spread, with differences in fiber density, and the pulp fibers are concentrated in the areas where the water flow hits, and many fine pulp fibers fall out of the laminate.As a result, the generation of lint during use of the finished product is particularly effectively reduced.

[0042] The unevenness caused by this hydroentanglement is preferably such that shallow recesses are formed on the pulp surface side, and relatively high protrusions corresponding to the recesses are formed on the lyocell surface side. Such irregularities are formed by applying a water flow from the pulp surface side, and are particularly effective in preventing lint generation. The formation of unevenness by hydroentanglement can be achieved, for example, by making the conveying surface of a support such as a conveying wire or conveying mesh that conveys a laminated sheet formed by stacking the above-mentioned pulp sheet and nonwoven fabric sheet have unevenness or holes, and applying a water flow to the laminated sheet on this conveying surface to transfer the shape of the unevenness or holes to the sheet while entanglement is being performed.

[0043] The pitch of the unevenness of the unevenness-forming portion G is not limited, but as shown in FIG. 2A, it is preferable that the pitch L1 in the machine direction (first direction) MD during the manufacturing process is 1 to 8 mm, particularly 2 to 6 mm. The pitch L2 in the direction (second direction) CD perpendicular to the machine direction is also desirably 1 to 8 mm, particularly desirably 2 to 6 mm. The pitch refers to the distance between regularly-spaced recesses (or between regularly-spaced protrusions).

[0044] It is preferable that the diameters W1 and W2 of the projections and recesses in a plan view are each 1 to 8 mm, particularly 2 to 6 mm. If the shape is not circular, for example an ellipse, the average of the major and minor axes is taken as the diameter. For other shapes, the equivalent diameter is taken as the diameter, because it is directly related to the water flow permeable area.

[0045] The spacing distances S1, S2 of the unevenness in plan view are each preferably 0.4 to 4 mm, and more preferably 0.8 to 2.5 mm.

[0046] The degree of unevenness of the unevenness forming portion G is, for example, as follows. In the cross sections taken along the first and second directions shown in FIG. 4B, at least one of the sides has a distance H1 between the top and bottom of 0.15 to 1.0 mm, and preferably 0.4 to 0.8 mm. The depth d of the recesses in the unevenness formation portion in FIG. 4B may be 0 to 0.3, and preferably 0.05 to 0.15 mm. The distance H2 between adjacent concave-convex portions in FIG. 4B may be 0.15 to 0.6 mm, and preferably 0.2 to 0.45 mm. The depth D between adjacent concave-convex portions in FIG. 4B may be 0.15 to 1.0 mm, and preferably 0.4 to 0.8 mm. These dimensions can be measured using Keyence's 3D Shot VR-3200, as well as by taking cross-sectional photographs of cut frozen sheets.

[0047] The pulp composite nonwoven fabric product of the embodiment is obtained by entangling pulp fibers and cellulose fibers by hydroentanglement (spunlace method). An example of the production method in this case is a method for producing a pulp composite nonwoven fabric obtained by entangling fibers using a spunlace method, which is also called a spunlace nonwoven fabric or a spunlace-type nonwoven fabric. Therefore, the pulp composite nonwoven fabric product of this embodiment may have fibers unevenly distributed in the thickness direction, such as one side having an excess of pulp fibers and the other side having an excess of cellulose fibers, and the ratio of fiber types may be different on the front and back surfaces.

[0048] Here, as shown in FIG. 5, a first example of a method for manufacturing a pulp composite nonwoven fabric product involves laminating a pulp sheet PS made of pulp fibers with a cellulose sheet CS, which is a nonwoven fabric made of cellulose fibers formed by a spunbonding method, meltblowing method, or the like, and then spraying water onto the dry pulp sheet surface of the laminated sheet in a manner similar to spunlace technology, also known as water jet technology, water needle technology, or the like, to destroy the bonds between the pulp fibers in the pulp sheet and hydroentangle the cellulose fibers and pulp fibers of the cellulose sheet CS. When lyocell fibers are used, the cellulose sheet CS used is a lyocell fiber web after carding.

[0049] In Fig. 5, at the hydroentanglement site, a support 40 having a mesh or holes is moved at the same speed as the sheet. If necessary, a drying device 50 is provided, and the sheet is finally wound up by a winder 60. Reference numeral 41 denotes a water spray nozzle, which is provided as required, for stabilization prior to hydroentanglement. In this hydroentanglement, the fiber length and fiber thickness of the pulp fibers and cellulose fibers derived from coniferous trees as described above are particularly desirable. The pulp sheet and the nonwoven fabric sheet may be laminated in multiple layers, but it is desirable to have one layer of each.

[0050] In addition, in this hydroentanglement, it is preferable to use a pulp sheet that is not made of paper that has been made by papermaking and drying, but rather a pulp solution in which pulp fibers are dispersed and suspended in water, which is discharged onto a conveying plane and compressed and dried using a heated drum to form a sheet. The drying temperature is 85 to 115° C., and preferably 90 to 110° C. This dried pulp sheet has low longitudinal and transverse fiber orientation and an extremely small aspect ratio difference in dry tensile strength, so that uneven entanglement is unlikely to occur. Details of the means for obtaining the pulp sheet PS are not shown in Fig. 5. A sheet forming means 42 for obtaining the pulp sheet PS can also be incorporated into the line shown in Fig. 5.

[0051] In the hydroentanglement, the nozzle diameter of the nozzle for spraying the water stream is preferably 0.5 to 1.5 mmφ, more preferably 0.75 to 1.25 mmφ. This nozzle diameter is smaller than that of the nozzle system used in the conventional spunlace method for pulp composite nonwoven fabric products. The water pressure is not necessarily limited, but is preferably 350 to 450 bar, and particularly preferably 380 to 420 bar. This water pressure is higher than the general water pressure (80 to 90 bar). By spraying a water stream at high pressure from a small-diameter nozzle against the pulp sheet, the entanglement of the pulp fibers and the regenerated cellulose fiber nonwoven fabric sheet is improved, and in particular, the penetration of the pulp fibers into the surface side of the regenerated cellulose fiber nonwoven fabric sheet is improved, making it difficult for the pulp fibers to separate from the front and back, and making it difficult for lint to occur. In addition, pulp fibers derived from coniferous trees and a nonwoven fabric sheet of regenerated cellulose fibers having a fiber length of 21 mm or more and 78 mm or less are particularly suitably entangled in the spunlace method under these conditions.

[0052] A second example of the method for producing a pulp composite nonwoven fabric product is shown in FIG. 6, in which pulp fibers are layered on a cellulose sheet CS while being conveyed. In FIG. 6, the support 40 shown in FIG. 5 is omitted.

[0053] In the second example, a fiber stacking machine 70 is provided, and a suspension of defibrated pulp fibers is passed through, for example, a drum drying section (not shown) to dry the pulp fibers, which are then stacked on the cellulose sheet CS while being transported. The other elements are the same as those in the first example of FIG. 5, so only the reference numerals are shown.

[0054] In the third example shown in Figure 7, a first stacker 71 and a second stacker 72 are provided for a support body 40, and cellulose fibers that have been defibrated from the first stacker 71 are stacked on top of the support body 40, and then pulp fibers that have been defibrated from the stacker 72 are stacked on top of the cellulose fibers while being transported. The other elements are the same as those in the first example of FIG. 5, so only the reference numerals are shown.

[0055] The specific dry tensile strength and wet tensile strength of the pulp composite nonwoven fabric product of this embodiment are not necessarily limited, but are preferably 30 to 80 N / 50 mm in the machine direction and 10 to 25 N / 50 mm in the cross direction both in the dry and wet states. If the strength is within this range, it is sufficient for wiping. The dry tensile strength and wet tensile strength are measured based on JIS L 1913 (2010) "6.3 Tensile strength and elongation (ISO method)". Specific examples of measuring devices include Minebea Co., Ltd.'s "Universal tension and compression tester TG-200N" and its equivalents.

[0056] On the other hand, it is desirable that the MMD (variation of coefficient of friction) on both sides of the pulp composite nonwoven fabric product of this embodiment is 6.0 or less. MMD is an index of smoothness. If the MMD is within the above range, it can be said that the smoothness of the pulp composite nonwoven fabric product is sufficient. The MMD is a value measured using a friction tester KES-SE, KES-SESRU, or an equivalent device manufactured by Kato Tech Co., Ltd. MMD is the degree of variation from MIU (mean coefficient of friction), and the smaller the value, the smoother the result. The measurement conditions are that the contact surface of the frictional element is brought into contact with the surface of the measurement sample to which a tension of 20 g / cm is applied in a specified direction with a contact pressure of 25 g, and the frictional element is moved 2 cm in approximately the same direction as the tension is applied at a speed of 0.1 cm / s. The measurement is performed five times, and the average value is taken as the MMD. The friction element is a piano wire sensor that comes standard with the above tester. This piano wire sensor is made of 20 adjacent piano wires with a diameter of 0.5 mm, and has a contact surface that is 10 mm long and 10 mm wide. The contact surface has a unit bulge at the tip that is made of 20 piano wires (with a curvature radius of 0.25 mm).

[0057] On the other hand, the pulp composite nonwoven fabric product of this embodiment desirably has a softness value of 20 cN / 100 mm or less on both the front and back sides. If the softness value is 20 cN / 100 mm or less, the product feels supple and soft for general-purpose use. The softness was measured by the handle-o-meter method according to JIS L 1096 E. The test pieces were 100 mm x 100 mm in size, and the clearance was 20 mm. The measurements were made five times in the vertical and horizontal directions on both the front and back sides, and the average of the five measurements was expressed in units of cN / 100 mm.

[0058] As described above, the pulp composite nonwoven fabric product according to the present embodiment has excellent liquid absorption and strength even though it does not contain synthetic fibers derived from petroleum, and has excellent versatility suitable for cleaning, wiping, wiping off dirt and liquids from food, objects, and living organisms such as the human body. It also produces little lint and has excellent heat resistance. It also has sufficient flexibility and smoothness. EXAMPLES

[0059] Next, tests were carried out on the examples of the pulp-mixed nonwoven wipes according to the present embodiment (No. 3, No. 4), a conventional example of a pulp-mixed nonwoven wipe (containing polypropylene fiber PP: No. 5) corresponding to a commercially available product that does not have unevenness, and comparative examples of pulp-mixed nonwoven wipes that do not have unevenness (No. 1, No. 2). All of the examples were pulp-mixed nonwoven wipes made by hydroentanglement.

[0060] In the conventional example, pulp and synthetic fibers (polypropylene fibers) are entangled. In the examples and comparative examples, the water pressure during hydroentanglement is 395 to 400 bar, and in the comparative example, it is 230 bar. In the examples, the lyocell fiber has a thickness of 1.67 dtex and a fiber length of 38 mm, and the rayon fiber has a thickness of 1.33 dtex and a fiber length of 38 mm. The pulp fiber used is softwood kraft pulp. In each example, no fiber type other than that shown in Table 1 is used.

[0061] The unevenness has the shape shown in Figure 1, and the shape of each concave (convex) is an ellipse (minor axis W1 = 2.8 mm × major axis W2 = 3.0 mm) that is slightly elongated in the direction perpendicular to the flow direction (CD direction), and the pitch is 4.2 mm in the flow direction (MD direction) L1 and 4.5 mm in the direction perpendicular to the flow direction L2.

[0062] The test results are shown in Tables 1 to 6. The physical properties and the like for the Examples and Comparative Examples are shown in Table 1. Since the fiber proportions in the commercially available products are unknown, only the constituent fibers are shown. The test method was as follows.

[0063] A careful examination of Tests No. 1 to No. 4 leads to inference that the formation of concaves and convexes B is related to the water pressure at the time of water flow entanglement, but is also related to the nozzle shape, the distance from the sheet, the pitch of the unevenness-forming portion, the area of ​​the unevenness-forming portion, and the arrangement of the unevenness-forming portion.

[0064] (Tensile strength) Measurements were made based on JIS L 1913 (2010) "6.3 Tensile strength and elongation (ISO method). Dry and wet tensile strengths were measured. The test machine used was a load cell tensile tester TG-200N manufactured by Minebea Co., Ltd. Measurements were performed by clamping both ends of the test piece to the grips of the test machine, applying a tensile load to the sample in the vertical direction, and reading the indicated value (digital value) when the sample breaks. The tensile speed was 100 mm / min. Five sets of samples were prepared in both the vertical and horizontal directions and measurements were made five times each, and the average of the measured values ​​was taken as the tensile strength in each direction.

[0065] [Water absorption] The water absorption was measured according to the following (1) to (5). (1) Measure the mass of the test piece using an electronic balance (such as A&D HR300). (2) Pour 25°C water into a tray larger than the test specimen (e.g., inner dimensions: 215 mm x 160 mm) to a depth of approximately 20 mm. (3) The test piece is spread out and placed on a rigid flat net (e.g., 120 mm x 120 mm, mesh size 15 mm) that is larger than or equal to the test piece, and then lowered into the tray containing the water so that the test piece is immersed in the water so that it comes into contact with the water surface. (4) When the water has sufficiently soaked into the surface of the test piece, raise the net directly above the water surface, pinch a corner of the test piece with tweezers, and leave it in that position for 30 seconds. (5) After 30 seconds, the mass of the test piece that has absorbed water is measured using an electronic balance and calculated using the following formula: 2 Calculate the amount of water absorbed per unit. Water absorption (g / m 2 ) = ((Mass of the water-absorbed test piece measured in (4) above) - (Mass of the test piece measured in (1) above)) x 100 (Note: m 2 (Multiply by 100 to convert to

[0066] [Oil absorption amount] The oil absorption was measured as follows (1) to (5). (1) Measure the mass of the test piece using an electronic balance (such as A&D HR300). (2) In a tray larger than the test specimen (for example, inner dimensions: 215 mm x 160 mm), pour salad oil (Nissin Salad Oil: manufactured by Nisshin Oillio Group, Ltd.) at 25°C to a depth of approximately 20 mm. (3) The test piece is spread out and placed on a rigid flat net (e.g., 120 mm x 120 mm, mesh size 30 mm) that is larger than or equal to the test piece, and then lowered into the tray containing the salad oil so that the test piece is immersed in the oil so that it comes into contact with the oil surface. (4) When the salad oil has soaked into the surface of the test piece, raise the flat net directly above the oil surface, leave it there for 30 seconds, then pick up a corner of the test piece with tweezers and transfer the test piece to a pre-weighed measurement container. At this time, do not allow more than 30 seconds from when the flat net is raised above the oil surface and left there until it is transferred to the measurement container. (5) The mass of the measuring vessel containing the test piece is measured using an electronic balance, and the mass of the test piece after oil absorption is calculated by subtracting the mass of the measuring vessel from the measured mass. Then, the mass of the test piece after oil absorption is calculated by the following formula: 2 The oil absorption per unit is calculated. Oil absorption (g / m 2 ) = ((Mass of the oil-absorbed test piece measured in (4) above) - (Mass of the test piece measured in (1) above)) x 100 (Note: m 2 (Multiply by 100 to convert to

[0067] [Water absorption speed] The water absorption rate was measured as follows (1) to (4). (1) Prepare a 100 mm x 100 mm test piece. (2) Place the test piece on a stand (such as a tripod for an alcohol lamp) that has a hole with a diameter of 40 mm or more in the center, so that the center of the test piece is positioned over the hole. (3) 300 μl of water at 25° C. is dropped with a micropipette at a height of 10 mm from the surface of the test piece to any point near the center of the test piece. This dropping can be done, for example, with an AS ONE Pipette Guy PG-1000, set to 300. (4) The time from the moment the water from the micropipette contacts the test piece to the moment the water completely penetrates the test piece is measured with a stopwatch, and this time is taken as the water absorption rate (sec). The completion of penetration is determined by visually confirming that the glossy reflection of water disappears from the surface of the test piece.

[0068] [Softness] Measurements were performed using the handle-o-meter method in accordance with JIS L 1096 E. However, the test pieces were 100 mm x 100 mm in size, and the clearance was 20 mm. Measurements were performed five times each in the vertical and horizontal directions on the front and back sides, and the average of the five measurements was expressed in units of cN / 100 mm.

[0069] [MMD] (Frictional resistance MIU) Measurements were performed using an automated surface tester KES-FB-4-AUTO manufactured by Kato Tech Co., Ltd. The contact surface of the frictional element was brought into contact with the surface of the measurement sample to which a tension of 20 g / cm was applied in a predetermined direction at a contact pressure of 25 g, and moved 2 cm at a speed of 0.1 cm / s in approximately the same direction as the tension was applied. The frictional element was a standard accessory 10 mm square piano wire sensor (20 pieces). MMD and MIU were measured five times for each surface, and the average values ​​were calculated.

[0070] [Lint removal performance (lint view tester)] The lint removal performance (lint view tester) was measured as follows (1) to (4). (1) Prepare a test piece measuring 240 mm x 200 mm. (2) Fold the test piece in half and soak it in pure water. Then, place two pieces of 300 mm x 300 mm filter paper (125 g / m 2 ) are placed between five pieces of the sample. (3) The sample is sandwiched between filter paper and a 2.86 kg iron roll (diameter 65 mm, face length 2500 mm) is moved back and forth five times over the filter paper to dehydrate it. (4) The sample is separated from the filter paper, and the wet two-fold test piece is unfolded into one sheet, which is then placed on a carrier sheet and the number of lint particles adhering to the sample is measured using an IGT Lint View Tester (manufactured by IGT Sisting Systems Co., Ltd.). The tape used for this measurement is number "D," which has the strongest adhesive strength, and the measurement is performed in the direction of a length of 240 mm by a width of 50 mm. The lint particles to be counted are visible and are 0.5 mm or larger. (5) The N number is the average of the numbers of visible defects measuring 0.5 mm or larger, 0.75 mm, 1.0 mm, 2.0 mm, and 3 mm or larger, measured three times in both directions in the flow direction (a total of six measurements). (6) As a reference value, the value of the pulp-mixed nonwoven wipe of Conventional Example 1, which contains pulp fiber and synthetic fiber (polypropylene fiber) in a ratio of 80:20 and is entangled by hydroentanglement, is set to "1", and a relative value is calculated. Note that the reason for using relative values ​​is that the adhesiveness of the adhesive tape used for the measurement changes depending on the measurement environment and over time, and the absolute numbers vary widely. For reference, absolute numbers are also shown.

[0071] [Lint removal performance (paper dust amount / mirror)] The lint removal performance (amount of paper powder / mirror) was measured as follows (1) to (3). (1) Prepare a test piece measuring 405 mm x 280 mm. (2) After immersing the test piece in tap water, squeeze it out between the palm of your hand and wipe the mirror while it is still wet. (3) The state of the paper powder adhering to the mirror is visually confirmed, and the condition is evaluated by giving a score of 1 to 9 points relative to Comparative Example 1, which is set as the standard of 10.

[0072] [Lint removal performance (paper dust amount / count number)] The lint removal performance (amount of paper powder / count number) was measured as follows (1) to (3). (1) Prepare a test piece measuring 405 mm x 280 mm. (2) After immersing the test piece in tap water, squeeze it out between the palm of your hand and, while still wet, wipe a 60 mm x 60 mm acrylic plate. (3) An arbitrary 24 mm x 18 mm area from the wiped area is magnified using a KEYENCE One-Shot 3D Measuring Macroscope VR-3200, and the number of paper particles within that area is visually counted. The relative values ​​of each test shown in Tables 1 to 5 are values ​​where Conventional Example 1 is taken as 1.

[0073] [Table 1] [Table 2] [Table 3] [Table 4] [Table 5]

[0074] Looking at the results in Tables 1 to 5, it can be seen that there was little lint generation, and in particular, the fabric in which irregularities were formed by hydroentanglement had excellent surface smoothness and softness, and also generated little lint.

[0075] [Table 6] Looking at the test results in Table 6, the examples of the present invention had tensile strengths in both dry and wet conditions equal to or greater than those of the conventional examples in which the synthetic fiber was polypropylene. Furthermore, compared to the comparative examples in which the cellulose fiber was rayon, the difference in tensile strength between dry and wet conditions was small, and the strength did not decrease even when wet. In addition, the heat resistance temperature was excellent, with carbonization at 400 degrees without melting. Furthermore, the liquid absorbing properties, such as water absorbency, oil absorbency, and water absorption speed, were superior to those of conventional examples and commercially available products using synthetic fibers.

[0076] These results demonstrate that the pulp-mixed nonwoven fabric sheet according to the present invention has excellent strength in both dry and wet states, and also has excellent liquid absorbency, even though it does not contain synthetic fibers derived from petroleum. From the above results, it can be said that the pulp-mixed nonwoven fabric product of the present invention is suitable for use as a versatile pulp-mixed nonwoven fabric wipe that is suitable for cleaning, wiping, and wiping off dirt and liquids from food, objects, and living organisms such as the human body. [Explanation of symbols]

[0077] 10...pulp fiber layer, 20...cellulose fiber layer, 30...laminate, 40...support, 41...water spray nozzle, 42...sheeting means, 50...drying device, 60...winder, 70, 71, 72...fiber stacking machine, G...convexoconcave forming section, MD...machine direction (first direction), CD...orthogonal direction (second direction).

Claims

1. A pulp composite nonwoven fabric product in which pulp fibers and cellulose fibers different from the pulp fibers are hydroentangled, Basis weight: 30 to 90 g / m ２ and The surface and back are unevenly woven by water flow. A pulp composite nonwoven fabric product.

2. 2. The pulp composite nonwoven fabric product according to claim 1, wherein the blending ratio of the pulp fibers to the cellulose fibers is from (50:50) to (80:20).

3. 3. The pulp composite nonwoven fabric product according to claim 1 or 2, wherein the cellulose fibers have a fiber length of 21 mm or more and 78 mm or less.

4. The pulp composite nonwoven fabric product according to claim 1 or 2, wherein the cellulose fibers are naturally derived fibers selected from the group consisting of natural fibers derived from plants, rayon, polynosic, cupra, Tencel (registered trademark), lyocell, and cellulose fibers obtained by melt spinning.

5. 3. The pulp composite nonwoven fabric product according to claim 1, wherein the pitch of the projections and recesses is 2 to 6 mm in both the first direction and the second direction perpendicular thereto.

6. The pulp composite nonwoven fabric product according to claim 5, wherein the distance between the top and bottom on at least one side of a cross section along the first and second directions is 0.15 to 1.0 mm.

7. A method for producing a pulp composite nonwoven fabric product in which pulp fibers and cellulose fibers different from the pulp fibers are hydroentangled, comprising: The order of line directions is: laminating the pulp fiber layer on the cellulose fiber layer; and spraying a water flow from above the pulp fiber layer toward the laminate of fiber layers to hydroentangle the fibers. Without mechanical embossing, the unevenness is created on the front and back surfaces of the product by hydroentanglement. A method for producing a pulp composite nonwoven fabric product comprising the steps of:

8. The cellulose fiber layer is formed into a sheet and is continuously transported in one direction, 8. The method for producing a pulp composite nonwoven fabric product according to claim 7, further comprising the step of laminating the pulp fiber layer on the sheet of the cellulose fiber layer.

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