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JP-7856538-B2 - Method for manufacturing composite nonwoven fabrics

JP7856538B2JP 7856538 B2JP7856538 B2JP 7856538B2JP-7856538-B2

Inventors

  • 竹▲崎▼ 友紀子
  • 大篭 幸治

Assignees

  • 日本製紙クレシア株式会社

Dates

Publication Date
20260511
Application Date
20220929

Claims (9)

  1. A method for producing a composite nonwoven fabric, comprising at least a nonwoven fabric and a pulp fiber web manufactured by an airlaid method, A water flow entanglement step in which the nonwoven fabric and the pulp fiber web are subjected to water flow entanglement treatment, The addition step includes, after the water flow entanglement step, adding a chemical solution containing a wet paper strength agent and an anionic water-soluble polymer to the pulp fiber web. The wet-strength agent contains polyamide epichlorohydrin (PAE), and the anionic water-soluble polymer contains carboxymethylcellulose (CMC). A method for producing a composite nonwoven fabric, characterized in that, in the addition step, the ratio of the amount of anionic water-soluble polymer added to the amount of wet paper strength agent added is 1.00 or more, and the addition rate of the anionic water-soluble polymer to the oven-dry weight of the pulp fiber web is 0.50% or more and 3.50% or less, by which time the chemical solution is added to the pulp fiber web.
  2. The method for producing a composite nonwoven fabric according to claim 1, characterized in that, in the addition step, the chemical solution is added to the pulp fiber web such that the addition rate of the anionic water-soluble polymer relative to the oven-dry weight of the pulp fiber web is 1.00% or more and 3.50% or less.
  3. The method for producing a composite nonwoven fabric according to claim 1, characterized in that, in the addition step, the chemical solution is added to the pulp fiber web such that the ratio of the amount of the anionic water-soluble polymer added to the amount of the wet-strengthening agent added is 1.10 or more.
  4. The aforementioned addition step includes a pre-addition dewatering step in which the composite nonwoven fabric is dewatered by a dewatering device provided on the lower side, A method for producing a composite nonwoven fabric according to claim 1, characterized by comprising a chemical solution addition step of adding the chemical solution to the pulp fiber web by spraying using an additive device provided downstream of the dewatering device.
  5. In the aforementioned chemical solution addition step, the chemical solution is added in two separate steps, both by spray application. The method for producing a composite nonwoven fabric according to claim 4, characterized in that both the first and second chemical solutions are added to the pulp fiber web by the addition device provided downstream of the dewatering device.
  6. The method for producing a composite nonwoven fabric according to claim 4, characterized in that, in the chemical solution addition step, the chemical solution is a mixture of the wetting paper strength agent and the anionic water-soluble polymer, and is added to the pulp fiber web by spray spraying using the addition device.
  7. The method for producing a composite nonwoven fabric according to claim 4, characterized in that, in the chemical solution addition step, the chemical solution consists of two separate chemical solutions containing the wetting paper strength agent and the anionic water-soluble polymer without mixing, and each is added to the pulp fiber web by spray spraying using a separate addition device.
  8. The method for producing a composite nonwoven fabric according to claim 7, characterized in that, in the chemical solution addition step, one chemical solution containing the wetting paper strength agent is added to the pulp fiber web by spray spray using the addition device, and then within two seconds, the other chemical solution containing the anionic water-soluble polymer is added to the pulp fiber web by spray spray using the addition device.
  9. The aforementioned nonwoven fabric is a spunbond nonwoven fabric. The method for producing a composite nonwoven fabric according to claim 1, characterized in that the water flow entanglement step involves subjecting the spunbond nonwoven fabric and the pulp fiber web manufactured by the airlaid method, which is placed thereon, to a water flow entanglement treatment.

Description

This invention relates to a method for producing a composite nonwoven fabric by adding a wet-strengthening agent and an anionic water-soluble polymer. In recent years, in addition to paper products (sheets) made solely from pulp fibers and nonwoven fabrics made solely from synthetic fibers, composite nonwoven fabrics obtained by entangling pulp fiber sheets and synthetic (long) fiber nonwoven fabrics with water flow have been sold on the market. In the production of composite nonwoven fabrics obtained by entangling pulp fiber sheets and long-fiber nonwoven fabrics, when a wet-process pulp fiber sheet is used, chemical solutions (additives) such as paper strength agents are added during the production (papermaking) of the wet-process pulp sheet. On the other hand, when using a dry process (airlaid method) to form pulp fiber webs (sheets), it is difficult to uniformly add chemicals to the pulp fibers. Therefore, to impart functionalities such as texture, flexibility, and strength, chemical solutions are added after water jetting (water entanglement). The water jet allows pulp fibers to penetrate between long fibers, creating an intertwined structure between the two fibers. This allows for subsequent addition of chemical solutions, which can then be applied to the resulting composite fiber structure. As prior art documents relating to composite nonwoven fabrics, for example, Patent Document 1 discloses a nonwoven composite fabric with a high pulp content that is entangled by water pressure, characterized by comprising a nonwoven continuous filament support of about 30% by weight or less and a fibrous portion made of pulp of about 70% by weight or more. Furthermore, a method for manufacturing a nonwoven composite fabric is also described, characterized by layering pulp fiber layers on a nonwoven continuous filament support with a bond density of about 100 pin bond positions/square inch and a total bond area of about 30% or less, entangling each layer by water pressure to form a composite material, and then drying this composite material. Furthermore, Patent Document 2 discloses a composite nonwoven fabric in which a pulp fiber web obtained by an airlaid method is laminated and integrated onto a spunbond nonwoven fabric, characterized in that the pulp fiber web contains a paper strength agent and an amphoteric resin, and the amount of paper strength agent added, calculated based on its solid content, is 0.04 to 1.0% of the solid weight of the pulp fiber web, and the amount of amphoteric resin added, calculated based on its solid content, is 0.06 to 1.5%. It also describes a manufacturing apparatus for the composite nonwoven fabric, in which a suction device and a drying device are provided downstream of the water flow entanglement device to perform a dewatering treatment to remove moisture remaining in the pulp fiber web, followed by a drying treatment to complete the manufacturing of the composite nonwoven fabric. The suction device is, for example, a vacuum type that dewaters the composite nonwoven fabric from below after water flow entanglement, and a paper strength agent addition device is positioned above the suction device with the conveyed composite nonwoven fabric in between. Patent No. 2533260Japanese Patent Publication No. 2021-130888 This is a schematic diagram of a manufacturing apparatus for carrying out the manufacturing method of composite nonwoven fabric according to this embodiment. The following describes in detail embodiments for carrying out the present invention (hereinafter simply referred to as "this embodiment"). This embodiment is illustrative for explaining the present invention and is not intended to limit the present invention to the following content. The present invention can be appropriately modified and implemented within the scope of its gist. In the drawings, identical elements will be denoted by the same reference numeral, and redundant explanations will be omitted. Furthermore, unless otherwise specified, positional relationships such as top, bottom, left, and right shall be based on those shown in the drawings. Additionally, the dimensional ratios in the drawings are not limited to those shown. Furthermore, in composite nonwoven fabrics, the MD direction refers to the conveying direction (Machine Direction) during the manufacturing of the composite nonwoven fabric, and the CD direction refers to the width direction (Cross Direction) perpendicular to the conveying direction. A method for manufacturing a composite nonwoven fabric according to one embodiment of the present invention is a method for manufacturing a composite nonwoven fabric that includes at least a nonwoven fabric and a pulp fiber web manufactured by an airlaid method. The nonwoven fabric is not particularly limited, but is preferably a spunbond nonwoven fabric. Figure 1 shows a manufacturing method and apparatus for producing a composite nonwoven fabric by placing a pulp fiber web supplied by an airlaid device o