Search

JP-7855365-B2 - Composite nonwoven fabric roll

JP7855365B2JP 7855365 B2JP7855365 B2JP 7855365B2JP-7855365-B2

Inventors

  • 竹▲崎▼ 友紀子
  • 大岡 康伸
  • 大篭 幸治

Assignees

  • 日本製紙クレシア株式会社

Dates

Publication Date
20260508
Application Date
20220225

Claims (7)

  1. A roll of composite nonwoven fabric containing pulp fibers and synthetic fibers and obtained by spunlace treatment, It is embossed in a single ply and wound so that the winding length/roll volume is between 0.0050 m/ cm³ and 0.0085 m/ cm³ . The pulp fibers contain a wet paper strength agent and/or an anionic water-soluble polymer. Here, the amount of the wet-strengthening agent added is 0.35 to 2.00% by weight relative to the oven-dry weight of the pulp fibers, and/or the amount of the anionic water-soluble polymer added is 0.1 to 1.0% by weight relative to the oven-dry weight of the pulp fibers. A roll of composite nonwoven fabric, characterized in that the basis weight of the composite nonwoven fabric is 30 g/ m² or more and 69.0 g/ m² or less, the basis weight of the synthetic fiber is 8 g/ m² or more and 13 g/ m² or less, the depth of the emboss formed by the embossing process is 0.1 mm or more and 1.0 mm or less, and the tensile strength (DMDT) in the conveying direction during manufacturing when dry is 9.8 N/25 mm or more.
  2. The embossing depth of the composite nonwoven fabric after wetting is 0.5 mm or more. Herein, the embossing depth of the composite nonwoven fabric after wetting refers to the value measured after completely immersing the nonwoven fabric in water, squeezing it tightly until no more water droplets fall, and then spreading out the sheet, as described in claim 1 for the roll of composite nonwoven fabric.
  3. The roll of composite nonwoven fabric according to claim 1 or 2, characterized in that the water absorption capacity (T.W.A.) of the composite nonwoven fabric is 200 g/ m² or more and 400 g/ m² or less, and the water absorption rate is 1.5 sec or less.
  4. The embossed shape retention when wet (embossed depth when wet / embossed depth in dry state × 100) is 80.0% or higher. Herein, the embossing depth when wet refers to the value measured after completely immersing the nonwoven fabric in water, squeezing it tightly until no more water droplets fall, and then spreading out the sheet, as described in any one of claims 1 to 3.
  5. A roll of composite nonwoven fabric according to any one of claims 1 to 4, characterized in that the pulp fibers contain a wet-strengthening agent and an anionic water-soluble polymer.
  6. The roll of composite nonwoven fabric according to claim 5, characterized in that the amount of the wet paper strength agent added is 0.35 to 2.00% by weight relative to the oven-dry weight of the pulp fibers, and the amount of the anionic water-soluble polymer added is 0.1 to 1.0% by weight.
  7. The roll of composite nonwoven fabric according to claim 5 or 6, characterized in that the anionic water-soluble polymer is carboxymethylcellulose (CMC).

Description

This invention relates to a roll of composite nonwoven fabric composed of pulp fibers and synthetic fibers. In recent years, rolls of nonwoven fabric wipes, manufactured from paper or nonwoven material and used as hand towel rolls, kitchen towel rolls, etc., have become commercially available. Among these, composite nonwoven fabric wipes, manufactured by intertwining synthetic fibers with pulp fibers using water flow, are particularly well-suited for repeated use in wiping tasks. These composite nonwoven fabrics are known to come in thick and thin varieties. While thicker wipes offer superior absorbency, their workability is inferior for tasks involving folding and wiping light spills, rather than handling large quantities of liquid. Therefore, thinner wipes tend to be preferred. Furthermore, making the wipes thinner reduces the overall product weight for the same number of sheets, making them easier to carry and fold for use. Therefore, for example, Patent Document 1 discloses a thin nonwoven fabric wiper (sheet) obtained by setting the average fiber length of pulp fibers, the basis weight of the composite nonwoven fabric, and the composition ratio of pulp fibers to synthetic fibers within a predetermined range. Japanese Patent Publication No. 2018-193634 This figure shows the height profile on the X-Y plane as measured by a microscope, indicated by varying shades of gray.This figure shows the height profile on the X-Y plane as measured by a microscope.This diagram is shown to explain how to determine the depth of the embossing.This figure shows a suitable apparatus for manufacturing the nonwoven fabric according to the present invention. The following describes the roll of composite nonwoven fabric according to the present invention. The inventors conducted a detailed examination of the state of synthetic fibers and pulp fibers on the walls of embossed areas (recesses or protrusions) when a thin composite nonwoven fabric is embossed. The synthetic fibers and pulp fibers located on the walls of the embossed areas are compressed. It was found that, in thin composite nonwoven fabrics, the number of pulp fibers, especially on the walls, decreases significantly, and the strength that holds the walls in place decreases considerably. As a result, it was understood that, as pointed out in the aforementioned problem, an improvement in wiping performance cannot be expected even when a thin composite nonwoven fabric is embossed. Therefore, after conducting detailed technical studies, we discovered that by designing a roll body of a composite nonwoven fabric that is embossed in a single ply, with the basis weight of the composite nonwoven fabric and the synthetic fibers contained therein within a predetermined range, the embossing depth within a predetermined range, the tensile strength in the MD direction (DMDT) when dry within a predetermined range, and furthermore, the value of the roll length/roll volume within a predetermined range, it is possible to obtain a roll body of a composite nonwoven fabric that is thin but has excellent embossing shape retention, and excellent wipeability, workability, and water absorption in both dry and wet conditions, which led to the present invention. The basis weight of the composite nonwoven fabric is preferably 30 g/ m² to 69.0 g/ m² , and more preferably 45 g/ m² to 65.0 g/ m² . Conventionally, most nonwoven fabrics widely used have a basis weight of around 100 g/ m² , so it can be seen that the composite nonwoven fabric of the present invention is a considerably thin nonwoven fabric. Here, it is preferable that the basis weight of the synthetic fibers constituting the composite nonwoven fabric be between 8 g/ m² and 13 g/ m² . If the basis weight of the synthetic fibers is less than 8 g/ m² , it deforms with heat during embossing, resulting in insufficient structure to maintain shape and poor embossing shape retention. On the other hand, if the basis weight exceeds 13 g/ m² , the embossing height becomes excessively high, resulting in a shorter winding length (reduced winding density). The thickness (mm) of a single ply of composite nonwoven fabric can be measured using a Peacock thickness gauge under a load of 37.85 g/cm². Furthermore, it is preferable that the composite nonwoven fabric is embossed in a single ply, and the depth of the embossing is 0.1 mm or more and 1.0 mm or less. The preferred depth range for this embossing is that if it is less than 0.1 mm, the embossing becomes too small, making it difficult to scrape off fine dirt particles with the embossed areas (recesses). If it is 1.0 mm or more, the roll must be wound more loosely to ensure sufficient embossing depth, resulting in a shorter roll length. The depth of the embossing can be measured using a microscope. The KEYENCE VR-3100 One-Shot 3D Measurement Microscope can be used. The VR-H1A software can be used for observing, measuring, and analyzing the microscope images. Measurement conditions can be set, for