CN215251970U

CN215251970U - Sheet paper for absorbent article

Info

Publication number: CN215251970U
Application number: CN202022920544.3U
Authority: CN
Inventors: 糸井隆; 铃木佑佳
Original assignee: Kao Corp
Current assignee: Kao Corp
Priority date: 2019-12-20
Filing date: 2020-12-08
Publication date: 2021-12-21
Anticipated expiration: 2030-12-08
Also published as: RU205866U1; JP3225370U

Abstract

The present invention relates to an absorbent article sheet containing an antimicrobial agent, having a dry tensile strength of 700cN/25mm or more in one direction and a void ratio of 5% or more. According to the absorbent article sheet of the present application, all of the antibacterial properties, liquid permeability and strength can be achieved. The present application also relates to an absorbent article having the sheet paper for an absorbent article.

Description

Sheet paper for absorbent article

Technical Field

The present application relates to sheet paper for use in absorbent articles such as disposable diapers, urine absorbent pads and the like.

Background

In absorbent articles such as sanitary napkins, diapers, and urine pads, a sheet of paper is used as a core-wrapped sheet for wrapping an absorbent core. Various techniques have been proposed for the sheet paper.

For example, patent document 1 describes a sheet paper containing 0.01g/m²The cationic antibacterial agent has high deodorizing ability, has a wrinkling rate of 5% to 30%, and has a soft touch and extensibility when wet.

Patent document 2 describes that a paper strength enhancer is added to a sheet of paper, mainly composed of an aggregate of 2 kinds of hydrophilic cellulose fibers having different fiber thicknesses, in order to obtain excellent strength characteristics and liquid permeability.

Patent document 1: japanese patent laid-open publication No. 2016-

Patent document 2: japanese laid-open patent publication No. 2012-144833

Disclosure of Invention

The present application provides an absorbent article sheet containing an antimicrobial agent, having a dry tensile strength of 700cN/25mm or more in one direction and a void ratio of 5% or more.

The above and other features and advantages of the present application will become further apparent from the following, when taken in conjunction with the accompanying drawings, where appropriate.

Drawings

Fig. 1 is a drawing obtained by taking a surface of a sheet of paper for an absorbent article at an observation magnification of 60 times with a microscope instead of a photograph.

FIG. 2 is an explanatory view of a method for measuring a liquid permeation time.

Description of the reference numerals

91,92: cylinder

93: clamp apparatus

94: filler material

S: sample (I)

W: viscous liquid

Detailed Description

The present invention relates to a sheet paper for absorbent articles, which can realize all of antibacterial properties, liquid permeability, and strength.

In order to impart antimicrobial properties to sheet paper, it is common to incorporate antimicrobial agents into sheet paper. On the other hand, when the antibacterial agent is contained, it becomes difficult to obtain sufficient strength of the sheet paper. That is, the antibacterial property and strength of the sheet paper are inversely related, and it is difficult to achieve both of them.

Further, when thick pulp is used as a raw material in order to improve the liquid permeability of the sheet paper, it becomes difficult to obtain sufficient strength of the sheet paper. That is, there is a trade-off between liquid permeability and strength, and it is difficult to achieve a good balance.

Therefore, it is more difficult to achieve all of the antibacterial properties, high liquid permeability, and sufficient strength in the sheet paper, and there is room for improvement in the prior art.

According to the absorbent article of the present application, all of the antibacterial properties, liquid permeability, and strength can be achieved.

A preferred embodiment of the absorbent article sheet of the present application will be described in order from the physical properties of the absorbent article sheet.

(Dry tensile Strength)

The absorbent article sheet paper (hereinafter also simply referred to as "sheet paper") of the present application has antibacterial properties and has a dry tensile strength of 700cN/25mm or more in one direction. The dry tensile strength is the tensile strength of the sheet paper when the sheet paper is not wet but dry, and is measured by the method described later. When the dry tensile strength is equal to or higher than a certain level, the sheet paper has practically sufficient strength, and the sheet paper is less likely to break during the production of the absorbent article.

In the present application, the dry tensile strength may be 700cN/25mm or more in one direction. For example, when there are a conveying Direction (Machine Direction, MD Direction) and a width Direction (Cross Direction, CD Direction) perpendicular to the conveying Direction in the production of sheet paper, the requirement that the dry tensile strength is 700cN/25mm or more in any Direction is satisfied. The "one direction" is not limited to the MD direction and the CD direction.

The dry tensile strength of the sheet paper is preferably 800cN/25mm or more, more preferably 850cN/25mm or more, and even more preferably 900cN/25mm or more, from the viewpoint of making the sheet paper less likely to break in the direction (for example, MD direction) satisfying the dry tensile strength of 700cN/25mm or more.

In this direction, the dry tensile strength of the sheet is preferably 1500cN/25mm or less, more preferably 1200cN/25mm or less, and even more preferably 1100cN/25mm or less, from the viewpoint of reducing the basis weight of the sheet.

On the other hand, the dry tensile strength of the sheet paper is preferably 150cN/25mm or more, more preferably 180cN/25mm or more, and further preferably 200cN/25mm or more, from the viewpoint of making the sheet paper less likely to break in a direction (for example, CD direction) orthogonal to the direction satisfying the dry tensile strength of 700cN/25mm or more.

In this direction, the dry tensile strength of the sheet is preferably 350cN/25mm or less, more preferably 300cN/25mm or less, and even more preferably 250cN/25mm or less, from the viewpoint of keeping the basis weight of the sheet constant or less.

(method of measuring Dry tensile Strength)

The sheet paper to be measured was left to stand at room temperature of 23 ℃. + -. 2 ℃ and relative humidity of 50% RH. + -. 2% for 12 hours, and humidity was adjusted so as to be in a constant state. The sheet paper after humidity adjustment was cut out in a rectangular shape of 40mm in the MD direction and 25mm in the CD direction to prepare a sample. This sample was mounted to a clip of a tensile tester (Autograph AG-1kN, manufactured by shimadzu corporation) without tension so that the MD direction was the tensile direction. The distance between the clips is 30 mm. The sample was pulled at a pulling rate of 300 mm/min, and the maximum strength until the sample broke was measured. The measurement was performed 5 times, and the average value of these values was defined as the dry tensile strength in the MD direction. Further, the sheet paper after humidity adjustment was cut out in a rectangular shape of 40mm in the CD direction and 25mm in the MD direction as a sample for the dry tensile strength in the CD direction. The sample was attached to a clip of a tensile testing machine without tension so that the CD direction was the tensile direction, and the dry tensile strength in the CD direction was determined by the same procedure as described above.

When the analysis is performed from a commercially available product or the like, a hot-melt adhesive used in the product can be deactivated by using a dryer, a cold spray, or the like, and each member can be carefully peeled off to obtain a target sheet. The method of taking out the sheet to be measured is common to the other measurements in this specification.

The sheet to be measured is measured for strength in the longitudinal direction and the transverse direction of the absorbent article, and is judged to be high in strength as the MD direction and low in strength as the CD direction. Generally, since a sheet paper used in an absorbent article is in a roll shape before being assembled in the absorbent article, the strength in the MD direction is high and the CD direction is low. The determination method in the MD direction and the determination method in the CD direction are common to the other measurements in the present specification.

(void fraction)

Further, in the absorbent article sheet of the present application, the void ratio is 5% or more. The void ratio in the present specification means a ratio of voids present on the surface of the sheet paper to the area of the sheet paper in a plan view. The higher the porosity, the higher the liquid permeability of the sheet paper.

From the viewpoint of improving the liquid permeability, the sheet paper preferably has a void ratio of 3% or more, more preferably 5% or more, and even more preferably 10% or more.

From the viewpoint of improving the dry tensile strength, the porosity of the sheet paper is preferably 20% or less, more preferably 15% or less, and still more preferably 12% or less.

(method of measuring porosity)

The sheet paper to be measured was cut out in a square shape of 30mm in the MD direction and 30mm in the CD direction to prepare a sample. The sample was placed on a sample stage of a microscope (trade name: VHX-1000, manufactured by KEYENCE K.K.) together with a black ring having an inner diameter of about 30mm and a height of about 10mm, and the sample was separated from the sample stage. A photograph of the surface of the sample shown in FIG. 1 was taken at 3 different positions with an observation magnification of 60 times using a general-purpose zoom lens (trade name: VH-Z20R, manufactured by KEYENCE) and a wide area illumination adapter (trade name: OP-87298, manufactured by KEYENCE). The photographed photograph was converted into a single color, the contrast was adjusted to 255, and the gamma was adjusted to 10, so that the holes on the surface of the sample were displayed in black. The Image subjected to such processing was analyzed by using Image-Pro Plus (version 6.2.0.424) as analysis software to measure the area of the hole portion.

The area of the holes measured as described above was divided by the area of the sample photographed in the photograph, and the average of the 3 points was defined as the porosity of the sheet.

(liquid permeation time)

In the present application, the liquid permeation time of the sheet paper is preferably 400 seconds or less. The shorter the liquid permeation time, the higher the liquid permeability of the sheet paper.

When such a sheet paper having a short liquid permeation time is applied to a core sheet of an absorbent article, excretion liquid such as urine can be rapidly permeated and rapidly absorbed by an absorbent core, and the leakage prevention property of the absorbent article can be improved.

(method of measuring liquid permeation time)

The sheet paper to be measured was cut out in a square shape of 20mm in the MD direction and 20mm in the CD direction to prepare a sample.

As shown in FIG. 2, 2

cylinders

91 and 92 having an inner diameter of 10mm and having openings at the upper and lower ends thereof were arranged vertically with the axes of the

cylinders

91 and 92 aligned, and the cut sample S was sandwiched between the upper and

lower cylinders

91 and 92. At this time, the upper and

lower cylinders

91,92 are coupled by fitting the jig 93 to annular flange portions provided at the lower end of the upper cylinder 91 and the upper end of the lower cylinder 92. The filler 94 has through holes having the same diameter and shape as the inner diameter of the

cylinders

91,92, and contains a material such as silicone. In this manner, 5.5 g. + -. 0.1g of a viscous liquid W having a viscosity of 290 mPas was supplied into the upper cylinder 91 in a state where the sample S was held and fixed by the upper and

lower cylinders

91, 92. The supplied viscous liquid W permeates through the sheet S to be measured or is absorbed by the sample S and disappears from the upper cylinder 91. The time from the start of the supply of the viscous liquid W until the liquid surface of the viscous liquid W fell from the surface of the sample S (the surface on the upper cylinder 91 side) to 4.5g was measured and the time was defined as the liquid permeation time.

The viscous liquid W was prepared by mixing glycerin and deionized water at a mass ratio of 94: 6. The viscosity of 290 mPas was measured at room temperature 23. + -. 2 ℃ and a relative humidity of 50% RH. + -.2% using a viscometer (trade name: TM-10M, manufactured by Toyobo Co., Ltd.).

(weight per unit area of sheet paper)

Of sheet paper for ordinary absorbent articlesThe weight per unit area is 20g/m²Above and 45g/m²In the present application, the sheet paper preferably has a basis weight of 10g/m from the viewpoint of improving dry tensile strength²Above, more preferably 11g/m²Above, it is more preferably 12g/m²The above.

In the present application, the weight per unit area of the sheet paper is preferably 16g/m from the viewpoint of improving the liquid permeability²Hereinafter, more preferably 15g/m²Hereinafter, more preferably 14.5g/m²The following.

The above-mentioned basis weight is a considerably smaller numerical range than that of a typical absorbent article sheet, and the absorbent article sheet of the present application has a high strength and excellent liquid permeability while having a basis weight in this range.

(method of measuring weight per unit area of sheet paper)

After adjusting the humidity under the conditions of JIS P8111, 10 sheets of the sheet paper to be measured were cut out in a square of 10cm to obtain a measurement piece. The mass of the measurement piece was measured with a balance, and the measured value was divided by the area (100 cm) of the measurement piece²) And the basis weight of the measurement piece was calculated. The basis weight of 10 sheets was calculated in the same manner, and the average was taken as the basis weight of the sheet.

Next, a material of the base material of the absorbent article sheet paper of the present application will be described.

As the base material of the absorbent article sheet paper of the present application, various materials can be used as long as the effects of the present application are exhibited. For example, cellulose fibers can be used as the main component.

As the cellulose, natural fibers and regenerated fibers can be used.

Specific examples of the natural fibers include wood pulp such as softwood kraft pulp (NBKP) and hardwood kraft pulp (LBKP), and non-wood pulp such as kapok pulp and grass pulp.

Examples of the regenerated fibers include rayon and cuprammonium fibers.

Synthetic fibers may be mixed into the base material of the absorbent article sheet paper of the present application.

Examples of the synthetic fibers include polyvinyl alcohol fibers, polyacrylonitrile fibers, polyethylene terephthalate (PET) fibers, Polyethylene (PE) fibers, polypropylene (PP) fibers, and polyester fibers.

In the present application, 1 kind of them may be used alone, or 2 or more kinds may be used in combination.

Among them, NBKP is preferably used.

Further, as the base material of the sheet paper, it is preferable to use pulp having a small fiber thickness (pulp having a small diameter) and pulp having a large fiber thickness (pulp having a large diameter) in combination. When pulp having a small fiber thickness is used, the dry tensile strength of the sheet paper generally becomes large. In addition, when pulp having a large fiber thickness is used, the liquid permeability of the sheet paper is generally improved. Therefore, by using both of these materials for a base material of a sheet paper, a sheet paper having both high dry tensile strength and excellent liquid permeability can be produced.

Specific examples of commercially available NBKP products used in the present application include Cenibra (trade name, fiber coarseness 0.09mg/m, manufactured by Cenibra), Northwood (trade name, fiber coarseness 0.13mg/m, manufactured by Confor), Cariboo (trade name, fiber coarseness 0.15mg/m, manufactured by Cariboo Pulp and Paper Company), Botnia (trade name, fiber coarseness 0.16mg/m, manufactured by BOTNIA Company), Alabama Pine (trade name, fiber coarseness 0.17mg/m, manufactured by Alabama Pine, manufactured by Inc.), ARAUCO (trade name, fiber coarseness 0.18mg/m, manufactured by AUARCO), Craron (trade name, manufactured by Unibra corporation), and the like. These PULPs can be obtained by Japan paper PULP Co.Ltd or Ito faithful Co.Ltd.

(antibacterial agent)

Next, the antibacterial agent contained in the absorbent article sheet of the present application will be described.

The antibacterial agent is a reagent that can impart antibacterial properties to an object, and the antibacterial properties can be judged by the antibacterial activity value. Specifically, JIS L1902²⁰¹⁵When the antibacterial activity value calculated by the antibacterial activity test method of the fiber product and the bacterial solution absorption method determined from the antibacterial effect is 2 or more, the object is determined to have antibacterial property. That is, the antimicrobial agent in the present application means an agent having an antimicrobial activity value of 2 or more in some cases contained in a sheet paper.

(weight per unit area of antibacterial agent)

The antimicrobial agent may be contained in the sheet paper in any weight per unit area as long as the effect of the present application is exhibited. Among them, from the viewpoint of imparting a certain level or more of antibacterial activity to the sheet paper, the weight per unit area of the antibacterial agent contained in the sheet paper is preferably 0.005g/m²Above, more preferably 0.01g/m²Above, more preferably 0.02g/m²The above.

In addition, the weight per unit area of the antimicrobial agent contained in the sheet paper is preferably 1g/m from the viewpoint of improving the dry tensile strength²Hereinafter, more preferably 0.5g/m²Hereinafter, more preferably 0.3g/m²The following.

When the antibacterial agent contained in the sheet paper is reduced, the dry tensile strength of the sheet paper is improved, which can be considered as follows.

Some of the antibacterial agents include those having hydrogen bond-inhibiting components (e.g., nitrogen and phosphorus) which are adsorbed to pulp, which is a raw material of sheet paper, and inhibit hydrogen bonding between cellulose fibers constituting the pulp. When the pulp is processed in a state in which hydrogen bonding is inhibited to produce a sheet paper, it is difficult for cellulose fibers in the sheet paper to form a strong bond with each other. Therefore, when the content of the antibacterial agent is small, hydrogen bonding between the cellulose fibers can be sufficiently formed, and the produced sheet paper is less likely to break and has improved dry tensile strength.

(method of measuring weight per unit area of antibacterial agent)

The weight per unit area of the antibacterial agent contained in the sheet paper can be measured by liquid chromatography/mass spectrometry (trade name: 6140LC/MS, manufactured by Agilent Technologies, ionization method: ESI). Alternatively, a calibration curve may be prepared, and the weight per unit area may be calculated based on the content of the antibacterial agent measured.

(kind of antibacterial agent)

As the antibacterial agent used in the present application, the antibacterial agent having the above-described antibacterial property can be used without particular limitation. Further, the antimicrobial agent may be used alone in 1 kind, or may be used in combination in 2 or more kinds.

Among them, a cationic antibacterial agent is preferable from the viewpoint of being an organic antibacterial agent, being more eluted into excretory fluid such as urine than a metal ion system such as silver, zinc, copper, and the like, and having a wide antibacterial action range. As the cationic antibacterial agent, there are cationic antibacterial agents described in paragraphs [0015] to [0018] of Japanese patent application laid-open No. 8-99841.

Among them, quaternary ammonium salts are preferable as the cationic antibacterial agent from the viewpoints of antibacterial properties and safety (low irritation to the skin).

Examples of the quaternary ammonium salt include an alkylpyridinium salt, a benzethonium salt, a benzalkonium salt, a monoalkyltrimethylammonium salt, and a dialkyldimethylammonium salt.

Among them, cetylpyridinium chloride, benzethonium chloride, dequalinium chloride, didecyldimethylammonium chloride and the like are preferable as the chloride.

Particularly, benzalkonium salts are preferred, and especially, benzalkonium salts of hexadecyl phosphate are preferred in view of high antibacterial activity, safety and immediate effect. Cetyl phosphate benzalkonium salt is a preferable agent for use in a sheet for an absorbent article because it has a good balance between antibacterial properties and low irritation to the skin (low water solubility) among organic cationic antibacterial agents and is highly safe.

Specific examples of the antibacterial agent used in the present application include SANISOL B-50 (registered trademark, alkylbenzyldimethylammonium chloride, manufactured by Kao corporation), SANISOL P-2 (registered trademark, cetylbenzylalkylammonium phosphate, manufactured by Kao corporation), and the like.

In addition, the antimicrobial agents used herein may have nitrogen or phosphorous, or both. As described above, nitrogen and phosphorus in the antibacterial agent generally cause a decrease in dry tensile strength of the sheet paper, but in the present application, the dry tensile strength can be increased by increasing the beating degree of the pulp as described later.

The above-mentioned SANISOL B-50 is an antibacterial agent having nitrogen. Further, the above-mentioned SANISOL P-2 is an antibacterial agent having both nitrogen and phosphorus.

(Dry paper strength agent)

The absorbent article sheet of the present application preferably contains a dry paper strength agent in addition to the antibacterial agent. The dry paper strength agent is a reagent contained in a sheet of paper in order to increase the tensile strength at the time of drying (i.e., dry tensile strength), and the reagent itself may be in a dry state or a wet state. By containing the dry paper strength agent, the dry tensile strength of the sheet paper is further improved. Further, the dry paper strength agent may be used alone in 1 kind, or may be used in combination in 2 or more kinds.

As the dry paper strength agent used in the present application, a dry paper strength agent that improves the dry tensile strength of sheet paper can be used without particular limitation. Among them, anionic dry paper strength agents are preferable. The dry paper strength agent is anionic, and therefore, can be neutralized by electric charge with a cationic agent (for example, the above-mentioned cationic antibacterial agent and a wet paper strength agent described later) contained in the sheet paper, and a large number of small pieces called blocks (blocks) can be formed in the process of producing the sheet paper.

In the process of manufacturing sheet paper, when papermaking is performed in a state in which blocks are formed, gaps are formed within the blocks having a complicated shape or between the blocks to an appropriate degree. As a result, a large number of holes are formed in the produced sheet, and the strength and porosity of the sheet can be improved by the block.

Further, from the viewpoint of forming a large amount of bulk, the dry paper strength agent preferably contains a compound having a large molecular weight.

Specific examples of the paper drying agent include carboxymethyl cellulose, dialdehyde starch, polyamide/epichlorohydrin resin, carboxymethyl cellulose, and polyacrylamide resin. Among them, polyacrylamide resins are preferable. The polyacrylamide resin corresponds to the above-mentioned anionic dry paper strength agent.

Among the polyacrylamide resins, polyacrylamide resins having a weight average molecular weight of 1000 to 2500 ten thousand are preferable, and polyacrylamide resins having a weight average molecular weight of about 1700 ten thousand are particularly preferable. That is, the absorbent article sheet of the present application preferably contains a polyacrylamide resin.

(compounding ratio of Dry paper powder)

The dry paper strength agent can be incorporated into the sheet paper at an arbitrary ratio as long as the effects of the present application are exhibited. Among these, from the viewpoint of improving the dry tensile strength of the sheet paper, the dry paper strength agent is preferably added in an amount of 0.001 mass% or more, more preferably 0.005 mass% or more, and still more preferably 0.01 mass% or more to the base material.

From the viewpoint of making the texture of the sheet paper uniform, the dry paper strength agent is preferably added to the base material in an amount of 0.2 mass% or less, more preferably 0.1 mass% or less, and still more preferably 0.03 mass% or less.

(Wet paper strength agent)

The absorbent article sheet of the present application may contain a wet paper strength agent. The wet paper strength agent is an agent contained in the sheet paper in order to improve the tensile strength at the time of wetting (i.e., wet tensile strength), and for example, polyamide/epichlorohydrin resin, melamine/formaldehyde resin, urea/formaldehyde resin, or the like can be used. The wet paper strength agent itself may be in a dry state or a wet state. The wet tensile strength of the sheet paper is improved by the inclusion of the wet paper strength agent. As a result, the sheet paper has sufficient strength even when it absorbs the excretory fluid, and is suitable for use in absorbent articles. The wet strength agent may be used alone in 1 kind, or may be used in combination in 2 or more kinds.

In general, the wet paper strength agent is a cationic agent.

(compounding ratio of Wet paper strength agent)

The wet paper strength agent can be blended in the sheet paper at an arbitrary ratio as long as the effects of the present application are exhibited. Among these, from the viewpoint of improving the wet tensile strength of the sheet paper, the wet strength agent is preferably added in an amount of 0.1 mass% or more, more preferably 0.3 mass% or more, and still more preferably 0.5 mass% or more to the base material.

From the viewpoint of making the texture of the sheet paper uniform, the moist paper strength agent is preferably added to the base material in an amount of 2 mass% or less, more preferably 1.5 mass% or less, and still more preferably 1.0 mass% or less.

(other Components)

The absorbent article sheet of the present application may contain other components in addition to the antibacterial agent, the dry paper strength agent, and the wet paper strength agent. Further, 1 kind of the other component may be used alone, or 2 or more kinds may be used in combination.

Examples of the other components include a polyol, a surfactant, a deodorant, various solvents generally used, an oil agent, a gelling agent, sodium sulfate, a salt such as N, N-trimethylglycine, a pH adjuster, an antioxidant, a preservative, a perfume, a pigment, an ultraviolet absorber, and a chelating agent.

The absorbent article sheet of the present application is typically used as a constituent member of an absorbent body constituting an absorbent article. Absorbent articles generally have a liquid-permeable topsheet, a liquid-permeable or liquid-impermeable backsheet, and an absorbent body sandwiched therebetween. The absorbent generally has an absorbent core having liquid retention properties and a core-wrapped sheet covering the outer surface of the absorbent core. The sheet paper for absorbent articles of the present application can be suitably used as a core-wrapped sheet.

Next, an example of a method for manufacturing the absorbent article sheet of the present application (hereinafter, also simply referred to as "manufacturing example") will be described.

The production example typically includes a beating step, a screen step, a papermaking step, a dewatering step, and a drying step in this order. The production example further includes an antibacterial agent addition step, a dry paper strength agent addition step, and a wet paper strength agent addition step. Hereinafter, each step will be explained.

(beating step)

The beating step is a step of mechanically breaking apart fibers of pulp, which is a raw material of the sheet paper. By performing beating of the pulp, fibrils on the fiber surface of the pulp increase, and hydrogen bonds of the pulp with each other can be increased. As a result, a sheet having high dry strength can be produced. The method of beating the pulp is not particularly limited as long as the sheet paper for absorbent articles of the present application can be produced. For example, a pulp obtained by dispersing pulp may be subjected to a conventional method using a known beater such as a refiner, a beater, a millstone refiner, or the like.

(degree of beating)

The degree of beating (i.e., freeness, degree of freedom) of the pulp can be determined by a value indicated by canadian standard freeness (c.s.f) specified in JIS P8121. In general, a smaller value of the degree of freedom indicates a stronger beating degree, and fibrillation advances as the damage of the fiber due to beating increases.

The freeness in the production example is preferably 700mL or less, more preferably 650mL or less, and even more preferably 580mL or less, from the viewpoint of improving the wet paper strength during processing and the dry paper strength of the sheet paper.

In addition, in the case of improving the productivity of the sheet paper by shortening the beating time, the beating degree in the production example is preferably 300mL or more, more preferably 400mL or more.

(Screen working procedure)

The screen process is a process of screening a slurry (papermaking raw material) obtained by dispersing pulp. By the screen, foreign matter in the slurry can be removed and the slurry can be uniformly dispersed.

The method of the screen is not particularly limited as long as the sheet paper for absorbent articles of the present application can be produced. For example, a method of sieving a slurry of about 1 ton per minute using a known sieve device is given.

(papermaking step, dewatering step and drying step)

The papermaking step is a step of forming a paper layer by papermaking the uniformly dispersed slurry on a papermaking net.

The dehydration step is a step of forming a wet paper web by performing dehydration such as pressing on the paper layer.

The drying step is a step of drying the wet paper using a yankee dryer, an air-through dryer, or the like to produce a sheet paper.

(antibacterial agent addition step)

The antimicrobial agent addition step is a step of incorporating an antimicrobial agent into the produced sheet paper. By going through the step of adding the antimicrobial agent, it is possible to produce an antimicrobial sheet paper by the production example.

The method of adding the antibacterial agent is not particularly limited as long as the sheet paper for absorbent articles of the present application can be produced. For example, a method of applying an aqueous solution of an antibacterial agent to a wet paper by spraying is mentioned. In the case of this method, the antibacterial agent addition step is performed after the dehydration step and before the drying step.

(step of adding Dry paper Strength agent)

The dry paper strength agent adding step is a step of adding a dry paper strength agent to the produced sheet paper. By going through the dry paper strength agent addition step, sheet paper having high dry tensile strength can be produced by the production example.

The dry paper strength agent addition step is preferably performed at least after the screen filtering step. The dry paper strength agent addition step may be added before the papermaking step. By adding a dry paper strength agent such as a polyacrylamide resin to the pulp slurry immediately before papermaking, papermaking can be performed in a state of forming a block, and the porosity of the produced sheet paper increases. As a result, a sheet having excellent liquid permeability and high dry tensile strength can be produced while containing an antibacterial agent.

(step of adding Wet paper Strength agent)

The wet paper strength agent addition step is a step of incorporating the wet paper strength agent into the produced sheet paper. By going through the wet paper strength agent addition step, a sheet of paper having a high wet tensile strength can be produced by the production example.

The wet strength agent addition step is preferably performed after the beating step and before the filtering step. By adding the wet strength agent to the slurry and then filtering the slurry, the wet strength agent can be uniformly dispersed in the slurry.

The manufacturing example may appropriately include steps other than those described above. For example, the method may further comprise a step of diluting the slurry with water or the like to a slurry concentration of 0.05 to 0.3% after the beating.

After the sheet paper is manufactured, the sheet paper is combined with other components of the absorbent article, whereby the absorbent article can be manufactured. For example, when using a sheet paper as the core sheet, an absorbent article can be obtained by wrapping an absorbent core with a sheet paper to prepare an absorbent body, and laminating the absorbent body with a topsheet and a backsheet.

Examples

The present application will be described in further detail below based on examples, but the present application is not construed as being limited thereto.

(example 1)

As NBKP, the sheet of the above-mentioned caribo (1 st pulp) and the sheet of the above-mentioned ARAUCO (2 nd pulp) were put into water at equal mass, and were disintegrated by a shredder. And beating the dissociated paper pulp by a refiner to obtain water pulp of the cellulose fiber raw material with the beating degree of 400 mL. At this time, the beating time per 1 ton of pulp was set to 60 minutes.

The cellulose fibers after beating were mixed with 0.7 mass% of a polyamide/epichlorohydrin resin (trade name: WS4024, available from Astro PMC Co., Ltd.) as a wet strength agent, and subjected to a screen. The cellulose fibers after the filtration were blended with 0.02 mass% of a polyacrylamide resin (trade name: ACCOFLOC A95, manufactured by AQUAPOLYMER K.K.) as a dry strength agent. A paper layer is formed on a cylinder wire using the papermaking raw material.

After the paper layer was dewatered by a press roll to obtain a wet paper, an aqueous solution of SANISOL P-2 (registered trademark, cetyl phosphate benzalkonium salt, manufactured by kao corporation) as an antibacterial agent was spray-coated using a spray nozzle (trade name: Unijet standard spray nozzle, flow size 0067, manufactured by Spraying Systems Japan). The wet paper after the spray coating was dried using a young's dryer, to obtain a sheet paper sample of example 1.

(example 2)

The same procedure as in example 1 was repeated except that the beating time per 1 ton of pulp was changed to 45 minutes and the beating degree was changed to 450mL, to obtain a sheet paper sample of example 2.

(example 3)

The same procedure as in example 1 was repeated except that the beating time per 1 ton of pulp was 20 minutes, the beating degree was 500mL, and the blending ratio of the dry paper strength agent to the cellulose fibers was 0.04%, to obtain a sheet paper sample of example 3.

(example 4)

The same procedures as in example 3 were repeated except that the beating time per 1 ton of pulp was changed to 10 minutes and the beating degree was changed to 550mL, to obtain a sheet paper sample of example 4.

(example 5)

A sample of the sheet paper of example 5 was obtained in the same manner as in example 2 except that SANISOL B-50 (registered trademark, alkylbenzyldimethylammonium chloride, manufactured by Kao corporation) was used as the antibacterial agent in place of SANISOL P-2.

(examples 6 and 7)

Other than changing the basis weight of the sheet, the sheet samples of examples 6 and 7 were obtained in the same manner as in example 1.

(example 8)

A sample of the sheet paper of example 8 was obtained in the same manner as in example 3, except that the weight per unit area of the sheet paper was changed.

Comparative example 1

A sample of the sheet paper of comparative example 1 was obtained in the same manner as in example 2, except that the sheet material not using aranco was used and the blending ratio of the dry paper strength agent to the cellulose fiber was changed to 0.04%.

Comparative example 2

A sheet paper sample of comparative example 2 was obtained in the same manner as in example 3, except that the dry paper strength agent was added before the screen, the mixing ratio of the dry paper strength agent to the cellulose fibers was set to 0.03%, and the antibacterial agent was not applied.

Comparative example 3

A sheet paper sample of comparative example 3 was obtained in the same manner as in example 3, except that no dry paper strength agent was added.

Comparative example 4

A sheet paper sample of comparative example 4 was obtained in the same manner as in example 2, except that no dry paper strength agent was added.

Comparative example 5

A sheet paper sample of comparative example 5 was obtained in the same manner as in example 1, except that no dry paper strength agent was blended.

Comparative example 6

A sheet paper sample of comparative example 6 was obtained in the same manner as in example 1, except that a dry paper strength agent was added before the screen.

(test)

For each sheet paper sample, the antibacterial activity value was measured by the above-mentioned JIS test method. Coli was used for the determination of the antibacterial activity value.

Further, for each sheet sample, the basis weight, dry tensile strength in MD, dry tensile strength in CD, porosity and liquid permeation time of the sheet were measured in the above-described manner.

The results are shown in tables 1 and 2.

[ Table 1]

[ Table 2]

As shown in tables 1 and 2, the sheet paper samples of examples 1 to 8 had an antimicrobial activity value of 2 or more, and had different antimicrobial properties from the sheet paper sample of comparative example 2 containing no antimicrobial agent.

In addition, the sheet paper samples of examples 1 to 8 all had a porosity of 5% or more, and therefore, the liquid permeation time was suppressed, and the liquid permeability was superior to the sheet paper samples of comparative examples 1 and 4 to 6, which had a small porosity.

Furthermore, the sheet paper samples of examples 1 to 8 all had a dry paper strength of 700cN/25mm or more in the MD direction, which was higher than that of the sheet paper sample of comparative example 3. The sheet paper sample of example 3 having the same basis weight as that of the sheet paper sample of comparative example 3 has high dry tensile strength, high porosity and excellent liquid permeability.

In this manner, all of the antibacterial properties, liquid permeability and strength were realized in the sheet paper samples of examples 1 to 8.

The present application has been described in conjunction with the embodiments and examples thereof, but the present application is not limited to any of the details of the description unless otherwise specified by the applicant, and it is considered that the present application should be broadly construed without departing from the spirit and scope of the invention as set forth in the appended claims.

The present application claims priority of japanese application 2019-004840, which was filed in japan for utility model registration on the basis of 12/20/2019, and is incorporated herein by reference as part of the description of the present specification.

Claims

1. A sheet paper for an absorbent article, characterized by containing an antimicrobial agent, having a dry tensile strength of 700cN/25mm or more in one direction and a void ratio of 5% or more.

2. The absorbent article sheet according to claim 1, wherein the dry tensile strength in the one direction is 800cN/25mm or more and 1500cN/25mm or less.

3. The absorbent article sheet according to claim 1, wherein the dry tensile strength in the one direction is 900cN/25mm or more and 1100cN/25mm or less.

4. The sheet paper for absorbent articles according to any one of claims 1 to 3, characterized in that the dry tensile strength in the direction orthogonal to the one direction is 150cN/25mm or more and 350cN/25mm or less.

5. The sheet paper for absorbent articles according to any one of claims 1 to 3, wherein the dry tensile strength in the direction orthogonal to the one direction is 200cN/25mm or more and 250cN/25mm or less.

6. The sheet paper for absorbent articles according to any one of claims 1 to 3, wherein the void ratio is 5% or more and 20% or less.

7. The sheet paper for absorbent articles according to any one of claims 1 to 3, wherein the void ratio is 10% or more and 12% or less.

8. The sheet paper for absorbent articles according to any one of claims 1 to 3, characterized in that the liquid permeation time is 400 seconds or less.

9. The sheet paper for absorbent articles as claimed in any one of claims 1 to 3, wherein said antibacterial agent has nitrogen or phosphorus, or both of them.

10. The sheet paper for absorbent articles as claimed in any one of claims 1 to 3, wherein the basis weight is 10g/m²Above and 16g/m²The following.

11. The sheet paper for absorbent articles as claimed in any one of claims 1 to 3, wherein the basis weight is 12g/m²Above and 14.5g/m²The following.

12. The sheet paper for absorbent articles according to any one of claims 1 to 3, characterized by containing a polyacrylamide resin.

13. The sheet paper for absorbent articles as claimed in any one of claims 1 to 3, wherein the antimicrobial agent is an organic cationic antimicrobial agent.

14. The sheet paper for absorbent articles as claimed in any one of claims 1 to 3, wherein said antibacterial agent is benzalkonium salt.

15. The sheet paper for absorbent articles as claimed in any one of claims 1 to 3, wherein said antibacterial agent is cetylphosphate benzylalkonium salt.

16. An absorbent article comprising the absorbent article sheet paper according to any one of claims 1 to 15.