JPH08141012A - Hydrophilic non-woven fabric and absorbent article using the same - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a hydrophilic non-woven fabric having high hydrophilicity and free from rust during the production of the non-woven fabric. [Structure] A surfactant mixture prepared by mixing polyoxyethylene alkyl ether sulfate or alkyl sulfate and alkyl phosphate metal salt in a weight ratio of 1: 3 to 3: 1 is added to 100 parts by weight of a nonwoven fabric. 05-
A hydrophilic non-woven fabric, characterized in that 2.0 parts by weight are adhered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrophilic non-woven fabric and an absorbent article using the hydrophilic non-woven fabric. More specifically, the hydrophilic non-woven fabric has high hydrophilicity and does not cause any problems in the manufacturing process. The present invention relates to an absorbent article using a hydrophilic nonwoven fabric as a surface sheet.

[0002]

Nonwoven fabrics are used as the surface material of absorbent articles such as disposable diapers and sanitary napkins. When the absorbent articles are worn, sweating, urine, In order to avoid discomfort caused by body fluid, it is considered important that the surface material is easily wetted and that the wettability is exhibited in a short time. Therefore, it is usually required that the fibers constituting the surface material, for example, the polyolefin fibers have hydrophilicity capable of absorbing liquid in a short time.

Conventionally, as methods for imparting hydrophilicity to the above surface material, the following methods (1) to (3) are known.

(1) Kneading a hydrophilizing material into a hydrophobic resin,
A method to obtain hydrophilic non-woven fabric using it as raw cotton. As this method, a method for producing hydrophilic fine fibers having a long fiber length from a multi-component mixed polymer having no compatibility (Japanese Patent Laid-Open No. Sho 4)
9-529), a method of thermally forming a film by adding a surfactant to polyolefin, and then performing corona discharge treatment (Japanese Patent Publication No. 1-49381).

(2) A method of forming hydrophilic groups on the surface by physical treatment such as UV, plasma treatment, corona discharge and the like. As this method, oxygen is excited with high-frequency energy under reduced pressure to be treated to carbonylate the surface (Japanese Examined Patent Publication No.
3-794).

(3) A method of attaching a hydrophilic compound. As this method, a method of attaching a fatty acid ester type nonionic surfactant having a high affinity to polyolefin fibers (JP-A-63-6166) and a method of using polyglycerin fatty acid ester (JP-A-2-216265) ).

However, in the above method (1), a large amount of the hydrophilic compound must be added to the polymer in order to knead the hydrophilizing material into the hydrophobic resin to exert sufficient hydrophilic performance. However, there is a problem that productivity is reduced and safety against heat or light is reduced.

Further, the method (2) has problems that it is inferior in mass productivity, requires a special device, or has a hydrophilic property which changes with time.

Although the method (3) is a simple method, in order to exert sufficient hydrophilic performance, the hydrophilic compound should be added in a large amount, or first, the hydrophobic activity should be obtained. It is necessary to maintain permeability and enhance durability by, for example, attaching the hydrophilic compound after attaching the agent,
Therefore, in any case, hydrophilic compounds such as alkyl ether sulfates and higher alcohol sulfates are mainly used in order to exhibit higher hydrophilicity. However, since these hydrophilic compounds have a sulfuric acid ester group as a hydrophilic group, rust is generated inside the heat treatment apparatus in the process of manufacturing a nonwoven fabric using thermoplastic fibers, and further the rust falls and mixes into the nonwoven fabric. Then, there is a problem that it causes foreign matter.

Therefore, an object of the present invention is to provide a hydrophilic non-woven fabric which has high hydrophilicity and does not cause rust during the production of the non-woven fabric.

[0011]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventor has found that an alkyl ether sulfate or a higher alcohol sulfate which has been conventionally used to impart hydrophilicity to a nonwoven fabric. It was found that the above object can be achieved by adhering a specific amount of a mixture obtained by mixing the above-mentioned and an alkyl phosphate metal salt in a specific mixing ratio to the nonwoven fabric.

The present invention has been made on the basis of the above-mentioned findings, and a polyoxyethylene alkyl ether sulfate or polyoxyethylene alkenyl ether sulfate or an alkyl sulfate or alkenyl sulfate and an alkyl phosphate metal salt in a weight ratio of 1: 3-
The non-woven fabric 10 was prepared by mixing the surfactant mixture prepared by mixing 3: 1.
The present invention provides a hydrophilic non-woven fabric characterized in that 0.05 to 2.0 parts by weight relative to 0 parts by weight (hereinafter referred to as "first invention" refers to this invention).

Further, the present invention provides an absorbent article comprising a liquid-permeable topsheet, a liquid-impermeable backsheet, and an absorber disposed between the two sheets, wherein the topsheet is the above-mentioned topsheet. The present invention provides an absorbent article (hereinafter referred to as "the second invention" when referred to as the present invention), which is characterized by being formed of the hydrophilic nonwoven fabric.

First, the hydrophilic non-woven fabric of the first invention will be described in detail below. As the alkyl group in the polyoxyethylene alkyl ether sulfate that can be used in the present invention, those having 8 to 22 carbon atoms are preferable, for example, octyl group, lauryl group, stearyl group, myristyl group, palmityl group, behenyl group, cetyl. Examples thereof include a group, but those having 12 to 18 carbon atoms are preferable from the viewpoint of improving the affinity with the fibers used for the nonwoven fabric.

Examples of the polyoxyethylene alkyl ether sulphate include polyoxyethylene (3) sodium lauryl ether sulfate, polyoxyethylene (7) cetyl ether sodium sulfate and the like. When used, they may be used alone or as a mixture of two or more kinds. Can be used as As the polyoxyethylene alkyl ether sulfate, it is possible to use a mixture of two or more compounds having different alkyl groups, and when the mixture is used, the mixture is 70% by weight of the mixture.
The above compound preferably has an alkyl group having 12 to 18 carbon atoms.

The alkenyl group in the polyoxyethylene alkenyl ether sulfate which can be used in the present invention preferably has 8 to 22 carbon atoms, and examples thereof include an oleyl group. From the viewpoint of improving the affinity of the above, those having 12 to 18 carbon atoms are preferable.

Examples of the polyoxyethylene alkenyl ether sulfate include polyoxyethylene (5) oleyl ether sodium sulfate. As the polyoxyethylene alkenyl ether sulfate, a mixture of two or more compounds having different alkenyl groups can be used. When the mixture is used, the mixture is 70% by weight or more of the compound. Preferably has an alkenyl group having 12 to 18 carbon atoms.

The alkyl group in the alkyl sulfate that can be used in the present invention has 8 to 22 carbon atoms.
Are preferred, for example, octyl group, lauryl group,
Examples thereof include stearyl group, myristyl group, palmityl group, cetyl group, behenyl group, and the like, and those having 12 to 18 carbon atoms are preferable from the viewpoint of improving the affinity with the fibers used in the nonwoven fabric.

Examples of the alkyl sulfates include sodium myristyl ether sulfate, sodium lauryl ether sulfate, sodium cetyl ether sulfate, sodium stearyl ether sulfate and the like, and when used, they can be used alone or as a mixture of two or more kinds. .
As the alkyl sulfate, a mixture of two or more compounds having different alkyl groups can be used, and when the mixture is used, the mixture contains 70% by weight or more of the compounds having carbon atoms. It preferably has 12 to 18 alkyl groups.

The alkenyl group in the alkenyl sulfate that can be used in the present invention has 8 to 8 carbon atoms.
No. 22 is preferable, and examples thereof include an oleyl group, and those having 12 to 18 carbon atoms are preferable from the viewpoint of improving the affinity with the fibers used in the nonwoven fabric.

Examples of the alkenyl sulfate include sodium oleyl ether sulfate. In addition, as the above-mentioned alkenyl sulfate, 2 of compounds having different alkenyl groups are used.
It is also possible to use a mixture of two or more species, and when the mixture is used, it is preferable that 70% by weight or more of the compound in the mixture has an alkenyl group having 12 to 18 carbon atoms.

The alkyl group in the above-mentioned alkyl phosphate metal salt that can be used in the present invention preferably has 8 to 22 carbon atoms.
Examples thereof include an octyl group, a caprin group, a capryl group, a lauryl group, a myristyl group, a palmityl group, and a stearyl group, and those having 8 to 12 carbon atoms are preferable from the viewpoint of improving the affinity with the fibers used in the nonwoven fabric.

Examples of the above-mentioned alkyl phosphate metal salts include potassium lauryl phosphate, potassium capryl phosphate, sodium caprin phosphate and the like, and when used, they can be used alone or as a mixture. As the alkyl phosphate metal salt, a mixture of two or more compounds having different alkyl groups can be used, and when the mixture is used, the mixture contains 80% by weight or more of the compound. 8 to 12 carbon atoms
It is preferable to have an alkyl group of

The above-mentioned surfactant mixture used in the present invention is the above polyoxyethylene alkyl ether sulfate or the above polyoxyethylene alkenyl ether sulfate (hereinafter, both are generically referred to as "sulfate compound") or the above alkyl sulfate salt or The above alkenyl sulfate (hereinafter, both are collectively referred to as “sulfate compound”) and the above alkyl phosphate metal salt are in a weight ratio of 1: 3 to 3: 1, preferably a weight ratio of 1: 2.
It is a surfactant mixture formed by mixing 2: 1. When the ratio of the weight of the alkyl phosphate metal salt to the weight of the sulfate compound or the sulfate compound is more than 3, hydrophilicity is decreased and leakage occurs at the time of use, and the sulfate compound or the sulfate compound is When the ratio of the weight of the above-mentioned alkyl phosphate metal salt to the weight 3 is less than 1, rust occurs during the production of the nonwoven fabric.

In the present invention, as the material of the non-woven fabric to which the surfactant mixture is attached, nylon, polyester resins, polyolefin resins such as polyethylene, or resins obtained by combining these resins can be used. Especially, polyethylene is preferable from the viewpoint of texture and cost. Further, the fibers constituting the non-woven fabric may be fibers made of the above material alone, but may be a mixture of other fibers, for example, having a high melting point resin such as polyethylene terephthalate or polypropylene in the core, the sheath The above-mentioned core-sheath structure composite fiber, which is a polyolefin resin, can be preferably used.

The thickness of the above fiber is 0.5 to 10d.
It is preferable to be, and it is more preferable to be set to 1.5 to 4d. The length of the fiber used for the non-woven fabric is 5
The thickness is preferably ˜55 mm, and more preferably 38-55 mm. Further, the basis weight of the non-woven fabric is 15 to 15.
It is preferably 30 g / m ² .

Thus, the hydrophilic non-woven fabric of the present invention contains the above surfactant mixture in an amount of 0.
It is a hydrophilic non-woven fabric obtained by adhering 05 to 2.0 parts by weight, preferably 0.1 to 0.5 parts by weight. When the amount of the above surfactant mixture attached is less than 0.05 parts by weight, hydrophilicity is not sufficiently expressed, and when the amount of the above surfactant mixture exceeds 2.0 parts by weight, the non-woven fabric becomes hard and the touch becomes poor. For example, it becomes unsuitable for use as a surface material for absorbent articles.

As a method for adhering the surfactant mixture to the nonwoven fabric, the surfactant mixture is made into an aqueous emulsion or the like and then dipped in the spinning and / or drawing step of the nonwoven fabric so as to have the above-mentioned adhering amount. A generally known method such as a spraying method or a spraying method can be applied as it is.

The hydrophilic non-woven fabric of the present invention is useful as a surface material (surface sheet) for absorbent articles such as disposable diapers and sanitary napkins, and is also used for cleaning sheets, wipes for wet wipes, cosmetic cotton, etc. You can also

Next, the absorbent article of the second invention will be described. The absorbent article of the present invention is an absorbent article comprising a liquid-permeable topsheet, a liquid-impermeable backsheet, and an absorber arranged between the two sheets, wherein the topsheet is It is formed of the hydrophilic non-woven fabric. Here, members other than the top sheet, that is, the back sheet and the absorber, can be used commonly known ones without particular limitation, other ordinary elastic members, fastening tapes and the like arranged as necessary. Can be arranged. Further, as the shape and the like of the surface sheet, the same shape and the like can be adopted as a normal absorbent article without any particular limitation. Further, as the surface sheet, the hydrophilic non-woven fabric may be used in combination with another liquid-permeable film or hydrophobic non-woven fabric.

[0031]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. In addition, the physical property evaluation method and the like in each example were performed as follows.

[Contact angle] 0.3 wt% of the surfactant mixture
An aqueous solution was added dropwise to a PE (polyethylene) plate and the contact angle was measured. As a device for measuring the contact angle, a product name “CA-A” manufactured by Kyowa Interface Science Co., Ltd. was used.

[Rust prevention test] Nail iron, the surface of which was washed with toluene, was dipped in a 0.3 wt% aqueous solution of a surfactant and stored at a storage temperature of 20 ° C and 40 ° C for 10 hours. Was observed and evaluated. The evaluation criteria are shown in [Table 1].

[Liquid permeation time] As shown in FIG. 1, the nonwoven fabric 1 obtained in Examples and Comparative Examples and the No. 5A filter paper 12 having a diameter of 55 mm were made of glass having a diameter of 35 mm with the filter paper 12 facing upward. The time until the artificial blood 14 (10 cm ² ) is inserted into the cylinder 13 from the height of 30 mm above and the artificial blood 14 starts to leak from below through the filter paper 12 and the nonwoven fabric 1 under constant pressure (t). ) Was measured. Note that the more hydrophilic the material, the shorter the required time (t).

[Surface Liquid Flow] As shown in FIG. 2, the non-woven fabric, which is a top sheet, was removed from a commercially available napkin, and the non-woven fabric 1 obtained in Examples and Comparative Examples was wound on the surface to obtain a measurement sample 21. . The non-absorption surface (back surface sheet side) of the measurement sample 21 is placed on the slope table 22 of the surface liquid flow measuring device, and the acrylic plate 23 is placed thereon. Next, from the lower end of the measurement sample 21 along the slope, 150 mm above, and from the height of 10 mm above the surface of the measurement sample 21, 1 g of artificial blood with the microtube pump 24.
Was dropped over 10 seconds, the distance from the point where the nonwoven fabric 1 was wet to the point where the artificial blood was first absorbed by the absorber was measured, and the average value of the 5 measurement samples was taken as the surface liquid flow.

[Examples 1 to 4, Comparative Examples 1 to 7] [Table 1]
Each of the components and the blending amount of the surfactant mixture shown in were adjusted. A 0.2% aqueous solution of the obtained surfactant mixture was mangle-treated on a non-woven fabric made of a polyolefin and having a basis weight shown in [Table 1] and prepared using a miniature card tester, and the above-mentioned surface activity was obtained. The agent mixture was adhered to the above-mentioned non-woven fabric in an amount shown in [Table 1] to obtain hydrophilic non-woven fabrics. The drawing ratio at this time was 150%. Here, the drawing ratio is calculated by the formula [(weight of non-woven fabric after deposition-weight of non-woven fabric before deposition) / weight of non-woven fabric before deposition]. The obtained hydrophilic nonwoven fabric was evaluated for liquid permeation time and surface liquid flow. Also,
The contact angle and rust-proof test were performed and evaluated about the said surfactant mixture. The results are shown in [Table 1].

[0037]

[Table 1]

[0038]

The hydrophilic non-woven fabric of the present invention has high hydrophilicity, and the hydrophilizing agent used can suppress the generation of rust in the heat treatment apparatus in the process of producing the non-woven fabric. Is less harmful due to the occurrence of. Further, the absorbent article of the present invention, since the surface sheet is formed by the hydrophilic nonwoven fabric, liquid absorption capacity,
It has excellent liquid permeability, and there is no fear that rust will mix into the surface sheet and cause deterioration during mounting.

[Brief description of drawings]

FIG. 1 is a principle diagram of a liquid permeation time evaluation method for absorbent articles.

FIG. 2 is a principle diagram of a surface liquid flow measuring method for absorbent articles.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Non-woven fabric 12 Filter paper 13 Cylinder 14 Artificial blood 15 Rubber packing 21 Measurement sample 22 Tilt table 23 Acrylic plate 24 Micro tube pump

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location D06M 13/262 D06M 13/32

Claims (4)

[Claims] 1. A surface activity obtained by mixing polyoxyethylene alkyl ether sulfate or polyoxyethylene alkenyl ether sulfate or alkyl sulfate or alkenyl sulfate with an alkyl phosphate metal salt in a weight ratio of 1: 3 to 3: 1. A hydrophilic non-woven fabric, characterized in that 0.05 to 2.0 parts by weight of the agent mixture is adhered to 100 parts by weight of the non-woven fabric. 2. The polyoxyethylene alkyl ether sulfate or the polyoxyethylene alkenyl ether sulfate is a mixture of two or more compounds having different alkyl groups or alkenyl groups, and 70% by weight or more of the compound in the mixture. Has an alkyl group or an alkenyl group having 12 to 18 carbon atoms, and the above-mentioned alkyl phosphate metal salt is a mixture of two or more compounds having different alkyl groups, and 80% by weight or more of the compound in the mixture. Has an alkyl group having 8 to 12 carbon atoms, The hydrophilic non-woven fabric according to claim 1, wherein 3. The alkylsulfate or alkenylsulfate is a mixture of two or more compounds having different alkyl groups or alkenyl groups, and 70% by weight or more of the compounds in the mixture have 12 to 18 carbon atoms. The alkyl phosphate metal salt having an alkyl group or an alkenyl group is a mixture of two or more compounds having different alkyl groups, and 80% by weight or more of the compound in the mixture has 8 to 12 carbon atoms. The hydrophilic non-woven fabric according to claim 1, which has the alkyl group of. 4. An absorbent article comprising a liquid-permeable topsheet, a liquid-impermeable backsheet, and an absorber arranged between the two sheets, wherein the topsheet comprises: An absorbent article formed of the hydrophilic nonwoven fabric according to any one of 1 to 3.