Composite nonwoven fabric

Abstract

To provide a composite nonwoven fabric that includes biomass plastic causing low environmental load, is excellent in shape retention when being folded, and also excellent in water absorptivity from a surface on spun-bonded nonwoven fabric side.SOLUTION: A composite nonwoven fabric is formed by laminating a spun-bonded nonwoven fabric including at least biomass plastic and a pulp fiber web and integrating the spun-bonded nonwoven fabric and the pulp fiber web by a water jet entanglement. The composite nonwoven fabric has basis weight of 45 g / m2 or more and 150 g / m2 or less and thickness of 0.35 mm or more and 1.00 mm or less, and breaking elongation rate at break in longitudinal direction of 40% or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a composite nonwoven fabric obtained by hydroentangling a pulp fiber web and a spunbond nonwoven fabric. [Background technology]

[0002] Paper towels, towel sheets, wipers and cloths are often used for cleaning oil stains around the kitchen, wiping with water, draining food, and wiping off dirt and dust from the surfaces of precision machinery such as cars and computers.

[0003] The materials for these sheets and wipers may vary depending on the application, but are often made of paper made of pulp fibers or nonwoven fabric made of synthetic fibers.

[0004] In recent years, sheets and wipers made of so-called composite nonwoven fabrics, in which pulp fibers and synthetic fibers are laminated or mixed, have also become well known.

[0005] One method for producing such composite nonwoven fabrics is to hydroentangle a spunbond nonwoven fabric made from pulp fibers, which have excellent absorbency for water-based and oil-based liquids, and synthetic fibers, which have excellent strength, to produce a sheet that combines strength and absorbency. In this case, the pulp fiber web can be supplied by a general wet papermaking method or dry airlaid, or can be supplied as a sheet produced by wet papermaking.

[0006] As an example of a prior art document on a composite nonwoven fabric produced by such hydroentanglement, Patent Document 1 describes a nonwoven fabric wiper obtained by hydroentanglement of a pulp fiber web and a synthetic fiber web, in which the average fiber length of the pulp fibers contained in the pulp fiber web is 1.0 to 5.0 mm, and the basis weight of the nonwoven fabric wiper is 20 to 42 g / m. 2 The nonwoven fabric wiper is characterized in that the composition ratio is 70 to 50 mass % of a pulp fiber web and 30 to 50 mass % of a synthetic fiber web. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2018-193634 A Summary of the Invention [Problem to be solved by the invention]

[0008] However, in the conventional composite nonwoven fabric configuration, the high stiffness of the sheets poses problems such as poor operability during folding processing and poor shape retention of the folded sheets when using the composite nonwoven fabric. This is because if the folded state is not maintained, gaps are generated between the laminated sheets when used for wiping, etc., making it difficult to apply force.

[0009] In addition, there is a high demand for biomass raw materials in terms of environmental impact. Furthermore, composite nonwoven fabrics have a spunbond nonwoven fabric side and a pulp fiber side, and there has been a demand for improving the water absorption (water absorption speed) of the spunbond nonwoven fabric side.

[0010] The present invention has been made in consideration of the above circumstances, and aims to provide a composite nonwoven fabric that contains biomass plastics, which has a low environmental impact, excellent shape retention when folded, and good water absorption from the spunbond nonwoven fabric side. [Means for solving the problem]

[0011] The inventors conducted extensive research and found that in a composite nonwoven fabric formed by laminating a spunbond nonwoven fabric containing at least a biomass plastic and a pulp fiber web and integrating them by hydroentanglement, it is possible to set the basis weight, thickness and longitudinal breaking elongation of the composite nonwoven fabric within predetermined numerical ranges, and by containing a biomass plastic, it is possible to obtain a composite nonwoven fabric which has a low environmental impact, excellent shape retention when folded, and good water absorption from the surface of the spunbond nonwoven fabric, thereby completing the present invention.

[0012] (1) The first aspect of the present invention is a composite nonwoven fabric obtained by laminating a spunbond nonwoven fabric containing at least a biomass plastic and a pulp fiber web and integrating them by hydroentanglement, and the composite nonwoven fabric has a basis weight of 45 g / m 2 More than 150g / m 2 The following is a composite nonwoven fabric characterized by having a thickness of 0.35 mm or more and 1.00 mm or less and a breaking elongation in the longitudinal direction of 40% or less.

[0013] (2) A second aspect of the present invention is the composite nonwoven fabric according to (1), characterized in that the content of biomass plastic in the spunbond nonwoven fabric is 50% or more.

[0014] (3) A third aspect of the present invention is the composite nonwoven fabric described in (1), characterized in that the biomass plastic contains at least polylactic acid (PLA), and the composite nonwoven fabric has a breaking elongation in the longitudinal direction of 20% or less.

[0015] (4) A fourth aspect of the present invention is the composite nonwoven fabric according to (1), wherein the spunbond nonwoven fabric has a basis weight of 10 g / m 2 More than 35g / m 2 It is characterized in that:

[0016] (5) A fifth aspect of the present invention is the composite nonwoven fabric according to (1), characterized in that the water absorption speed of the composite nonwoven fabric on the surface on which the spunbond nonwoven fabric is laminated is less than 0.85 seconds. Effect of the Invention

[0017] According to the present invention, a composite nonwoven fabric can be provided which contains biomass plastics, thereby reducing the environmental impact, has excellent shape retention when folded, and also has good water absorption from the spunbond nonwoven fabric side. [Brief description of the drawings]

[0018] [Figure 1] FIG. 2 is a schematic diagram illustrating a method for measuring the fold opening angle in the composite nonwoven fabric according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an embodiment for carrying out the present invention (hereinafter, simply referred to as "the present embodiment") will be described in detail. The present embodiment is an example for explaining the present invention, and is not intended to limit the present invention to the following content. The present invention can be carried out by appropriately modifying it within the scope of its gist. In addition, the MD direction of the composite nonwoven fabric is the machine direction in which the composite nonwoven fabric is manufactured, and the CD direction is the cross direction perpendicular to the machine direction.

[0020] <Composite nonwoven fabric> The composite nonwoven fabric according to this embodiment is formed by laminating a spunbond nonwoven fabric containing at least a biomass plastic and a pulp fiber web, and integrating the laminated layers by hydroentangling.

[0021] The biomass plastic contained in the spunbond nonwoven fabric is not particularly limited as long as it is an existing biomass plastic such as polylactic acid (PLA) or plant-derived polyethylene (PE), but it is preferable that it contains polylactic acid (PLA). The spunbond nonwoven fabric may further contain synthetic fibers such as nylon, vinylon, polyester, acrylic, polyethylene, polystyrene, and polypropylene, but in order to reduce the environmental impact, the content of biomass plastic in the spunbond nonwoven fabric is preferably 21% or more, and more preferably 50% or more. By having the content of biomass plastic within the above numerical range, it is possible to obtain a composite nonwoven fabric with a low environmental impact.

[0022] The pulp fiber web preferably comprises one or more bleached softwood kraft pulp (NBKP) fibers selected from the group consisting of radiata pine, slash pine, southern pine, lodgepole pine, spruce, and Douglas fir. In addition to softwood bleached kraft pulp (NBKP), general pulp fibers such as hardwood bleached kraft pulp (LBKP) may also be included, but it is preferable to include softwood bleached kraft pulp (NBKP) and hardwood bleached kraft pulp (LBKP). The content ratio of NBKP and LBKP in the pulp fibers is preferably 50:50 or more and 100:0 or less, more preferably 70:30 or more and 100:0 or less, even more preferably 90:10 or more and 100:0 or less, and most preferably 100:0.

[0023] The basis weight of the composite nonwoven fabric is 45g / m 2 More than 150g / m 2 Less than 50 g / m 2 More than 130g / m 2 The basis weight of the spunbond nonwoven fabric is preferably 10 g / m or less. 2 More than 35g / m 2 It is preferable that the thickness is less than 12 g / m 2 More than 30g / m 2 When the basis weights of the composite nonwoven fabric and the spunbond nonwoven fabric are within the above ranges, the composite nonwoven fabric can have excellent water absorbency and shape retention. The basis weight is measured in accordance with JIS P 8124.

[0024] The thickness of the composite nonwoven fabric is from 0.35 mm to 1.00 mm, and preferably from 0.40 mm to 0.90 mm. By having the thickness within the above numerical range, the composite nonwoven fabric can have excellent water absorbency and shape retention. The thickness of the composite nonwoven fabric is measured using a Peacock paper thickness gauge under a load of 3.7 kPa.

[0025] Furthermore, the water absorption speed of the composite nonwoven fabric on the surface on which the spunbonded nonwoven fabric is laminated is preferably less than 0.85 seconds, and more preferably less than 0.65 seconds. By having the water absorption speed within the above numerical range, a composite nonwoven fabric with excellent water absorption properties can be obtained. The water absorption rate is measured according to the dropping method specified in JIS L 1907, and the time (seconds) from when a 0.1 mL water drop reaches the surface of the test piece until the mirror reflection of the test piece disappears is measured.

[0026] The composite nonwoven fabric preferably has a longitudinal tensile strength of 10 N / 25 mm or more and 50 N / 25 mm or less, more preferably 15 N / 25 mm or more and 40 N / 25 mm or less, in a dry state. By having the tensile strength within the above range, the composite nonwoven fabric can have excellent shape retention.

[0027] Furthermore, the longitudinal breaking elongation of the composite nonwoven fabric is 40% or less, and preferably 20% or less. By having the breaking elongation within the above range, the composite nonwoven fabric can have excellent shape retention. The tensile strength and elongation at break in the machine direction are measured by a tensile tester using a 25 mm wide test piece cut from the composite nonwoven fabric. The measurement conditions are a chuck distance of 100 mm, a tensile speed of 300 mm / min, and an average value of four measurements (n=4). In this case, the machine direction of the composite nonwoven fabric refers to the direction parallel to the MD direction.

[0028] <Method of manufacturing composite nonwoven fabric> The method for producing the composite nonwoven fabric according to the present embodiment is a method in which a spunbond nonwoven fabric and a pulp fiber web are laminated and integrated by hydroentanglement. The integration process by hydroentanglement is described in detail, for example, in Japanese Patent No. 6758116. As a method for forming a web of pulp fibers, an air-laid method is preferred from the viewpoint of water absorbency.

[0029] The composite nonwoven fabric produced by the above-mentioned process is preferably used for daily use such as paper towels and kitchen towels, and for industrial use such as wipers and cloths. However, there are no particular limitations on its use as long as it is a mass-produced product for which consideration must be given to the environmental impact and is used for wiping off dirt and moisture.

[0030] As described above, according to the present embodiment, it is possible to provide a composite nonwoven fabric that contains biomass plastics, thereby reducing the environmental impact, has excellent shape retention when folded, and also has good water absorption from the spunbond nonwoven fabric side. EXAMPLES

[0031] The present invention will be described in more detail with reference to the following examples and comparative examples, but the present invention is not limited to the following examples in any way.

[0032] The composite nonwoven fabrics of Examples 1 to 16 and Comparative Examples 1 to 8 were produced under the conditions shown in Tables 1 and 2, and the following evaluations were carried out. Among the abbreviations shown in Tables 1 and 2, "biomass PE" means plant-derived polyethylene, and "PP" means polypropylene. The parameters other than those evaluated below were measured according to the above-mentioned standards or measurement methods. All measurements according to the above-mentioned standards or measurement methods were performed indoors at a temperature of 23° C. and a humidity of 50% RH.

[0033] (Environmental load) The environmental impact of manufacturing composite nonwoven fabrics was evaluated according to the following criteria, based on the content ratio of biomass plastics in the spunbond nonwoven fabric (biomass degree of the spunbond nonwoven fabric). 3: The biomass content of the spunbond nonwoven fabric is between 50% and 100% 2: The biomass content of the spunbond nonwoven fabric is 21% or more and 49% or less. 1: The biomass content of the spunbond nonwoven fabric is between 0% and 20%.

[0034] (Water absorption on the spunbond nonwoven fabric side) The water absorption rate of the spunbonded nonwoven fabric side of the composite nonwoven fabric was evaluated according to the following criteria based on the water absorption rate of the spunbonded nonwoven fabric side. 3: The water absorption speed of the spunbond nonwoven fabric side is less than 0.65 seconds 2: The water absorption speed of the spunbond nonwoven fabric side is 0.65 seconds or more and less than 0.85 seconds 1: The water absorption speed of the spunbond nonwoven fabric side is 0.85 seconds or more

[0035] (Folding shape retention) In order to evaluate the folded shape retention of the composite nonwoven fabric, the opening angle of the fold of the composite nonwoven fabric was measured as follows (hereinafter, an explanation will be given with reference to the schematic diagram shown in FIG. 1). First, the hydroentangled composite nonwoven fabric was cut to a length of 95 mm in the MD and 50 mm in the CD to obtain test piece 1. Next, as shown in Figure 1(a), test piece 1 was placed on a horizontal surface with the spunbond nonwoven fabric side (spunbond surface 10) facing up, and a line 2 was drawn with a marker at the center of test piece 1 at a position 25 mm away in the CD.

[0036] Next, as shown in FIG. 1(b), half of the test piece 1 is fixed to a horizontal surface with tape 3 along the line drawn in the above step. Then, as shown in Figure 1(c), the end of the test piece 1 was held and bent in half in the CD direction, and then a weight 4 with a base area of ​​97 mm × 97 mm and a weight of 800 g was placed on top of the bent test piece 1, aligned with one end of the tape, as shown in Figure 1(d).

[0037] After 5 minutes, the weight 4 was removed, and the opening angle θ of the folded test piece 1 was measured over time at 5 seconds, 10 seconds, 20 seconds, and every 10 seconds up to 120 seconds, as shown in Figure 1(e).

[0038] Finally, the folded shape retention of the composite nonwoven fabric was evaluated according to the following criteria based on the difference in the opening angle after 5 seconds and after 120 seconds. 3: The difference in the opening angle between 5 seconds and 120 seconds is less than 30° 2: The difference in the opening angle between 5 seconds and 120 seconds is between 30° and 45° 1: The difference in the opening angle between 5 seconds and 120 seconds is 45° or more

[0039] Tables 1 and 2 show the conditions and evaluation results for each of the examples and comparative examples. [Table 1]

[0040] [Table 2]

[0041] From the above, it was confirmed that this embodiment can produce a composite nonwoven fabric that contains biomass plastic, which has a low environmental impact, has excellent shape retention when folded, and also has good water absorption from the spunbond nonwoven fabric side. [Explanation of symbols]

[0042] 1 Test piece 2 wires 3. Tape 4 Weight 10 Spunbond surface

Claims

1. A composite nonwoven fabric comprising a spunbond nonwoven fabric containing at least a biomass plastic and a pulp fiber web laminated together and integrated by hydroentanglement, The basis weight of the composite nonwoven fabric is 45 g / m ２ 150g / m or more ２ The composite nonwoven fabric is characterized in that it has a thickness of 0.35 mm or more and 1.00 mm or less and a breaking elongation in the longitudinal direction of 40% or less.

2. The composite nonwoven fabric according to claim 1 , characterized in that the content of biomass plastic in the spunbond nonwoven fabric is 50% or more.

3. The biomass plastic contains at least polylactic acid (PLA), 2. The composite nonwoven fabric according to claim 1, wherein the composite nonwoven fabric has a breaking elongation in the longitudinal direction of 20% or less.

4. The spunbond nonwoven fabric has a basis weight of 10 g / m ２ 35g / m or more ２ 2. The composite nonwoven fabric according to claim 1, characterized in that:

5. 2. The composite nonwoven fabric according to claim 1, wherein the water absorption speed of the composite nonwoven fabric on the surface on which the spunbond nonwoven fabric is laminated is less than 0.85 seconds.

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