JP5064314B2 - Disposable diapers - Google Patents

Description

  The present invention relates to a disposable diaper which is not easily stuffy and has excellent moisture permeability and has a good feeling of use.

  In recent years, as a diaper for infants or the elderly or disabled, an absorbent body, a top sheet at least partially made of a liquid-permeable material, and arranged to cover the surface of the absorbent body, and liquid-impermeable Disposable diapers (for example, a tape-type diaper, a pants-type diaper, etc.) comprising a back material disposed to cover the back surface of the absorbent body made of a functional material are widely used.

  Among these disposable diapers, as the pants-type disposable diaper, for example, it is composed of each part of the front body, the crotch part, and the back body, and the corresponding side edges of the front body and the back body are joined together, There is known one in which one waist opening and a pair of leg openings are formed (see Patent Document 1). In such a pants-type disposable diaper, elastic materials such as rubber thread are disposed along the waist opening and the leg opening.

  The tape-type diaper is composed of, for example, the front body, the crotch part, and the back body, and includes an absorbent body, a top sheet disposed so as to cover the upper surface of the absorbent body, and the absorbent body. What is provided with the back sheet | seat arrange | positioned so that a lower surface may be covered, and the fastening tape arrange | positioned so that it may extend from each right and left side edge of a back body is known (refer patent document 2 and 3). ). Such a tape-type disposable diaper has an advantage that the wearer can easily attach the front body and the back body of the diaper with a fastening tape.

  The disposable diaper as described above is used so that the top sheet is in contact with the wearer's skin, and excrement is absorbed and held in the absorbent body through the liquid-permeable portion of the top sheet. And the excrement is prevented from leaking outside by the liquid-impermeable back sheet disposed on the back side of the absorber. Note that the back sheet is normally liquid-impermeable and moisture-permeable as described above from the viewpoint of preventing the diaper from being steamed.

Registered Utility Model No. 3024357 JP 2004-141532 A JP 2004-24307 A

  As described above, the back sheet constituting the disposable diaper has a certain degree of moisture permeability, but it is not always sufficient, and the inside of the diaper may be steamed when worn. A general back sheet is composed of a microporous plastic film having many fine pores of 0.1 to several μm. For this reason, if the diameter of the pores is increased or the number of pores is increased in order to increase the moisture permeability of the backsheet, the strength of the backsheet itself tends to be reduced. A diaper using a back sheet having a reduced strength may have a problem of facilitating leakage of excrement absorbed and held by the absorbent body to the outside while ensuring moisture permeability.

  The present invention has been made in view of such problems of the prior art, and the object is to provide a back sheet having excellent moisture permeability and sufficient strength, and is worn. An object of the present invention is to provide a disposable diaper that is not easily stuffy and is comfortable to use and that can reliably prevent leakage of excreta and the like.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors have achieved the above-mentioned problems by using a back sheet in which a specific leak-proof coating layer is formed on at least one side of a sheet-like support having air permeability. The inventors have found that it is possible to achieve this, and have completed the present invention.

  That is, according to this invention, the disposable diaper shown below is provided.

[1] An absorbent body, a top sheet at least partly made of a liquid-permeable material, and disposed so as to cover the surface of the absorbent body, and a back sheet disposed so as to cover the back surface of the absorbent body A sheet-like support made of a breathable material selected from a nonwoven fabric, a woven fabric, or paper , and a synthetic resin and an aspect formed on at least one side of the support A disposable diaper having a leak-proof coating layer containing a flat pigment having a ratio of 5 or more .

  [2] The disposable diaper according to [1], wherein the synthetic resin is a styrene-butadiene copolymer.

[3] The coating amount of the anti-Monuri coating layer is, the disposable diaper according to any one of the is 0.5 to 50 g / ^{m 2} [1] or [2].

[ 4 ] The disposable diaper according to any one of [1] to [ 3 ], wherein the moisture-proof coating layer has a moisture permeability of 3000 to 100,000 g / (m ² · 24h).

[ 5 ] The disposable diaper according to any one of [1] to [ 4 ], wherein the leak-proof coating layer is formed on at least one surface of the support with a precoat layer interposed.

  The disposable diaper of the present invention is excellent in moisture permeability and is provided with a back sheet having sufficient strength, it is hard to be stuffy when worn, has good comfort, and can reliably prevent leakage of excrement etc. There is an effect that it is possible.

  BEST MODE FOR CARRYING OUT THE INVENTION The best mode for carrying out the present invention will be described below, but the present invention is not limited to the following embodiment, and is based on the ordinary knowledge of those skilled in the art without departing from the gist of the present invention. It should be understood that modifications and improvements as appropriate to the following embodiments also fall within the scope of the present invention.

  The disposable diaper of the present invention is an absorbent body, a top sheet at least partially made of a liquid-permeable material, disposed so as to cover the surface of the absorbent body, and disposed so as to cover the back surface of the absorbent body. And a back sheet. And the disposable diaper of the present invention includes a sheet-like support made of a material having air permeability, and a leak-proof coating layer containing a synthetic resin formed on at least one side of the support. , Has.

  The back sheet having the above-described configuration is excellent in moisture permeability. For this reason, the disposable diaper of the present invention using such a back sheet is hard to be stuffy when worn, and is comfortable to use. Moreover, unlike the conventional back sheet comprised by the microporous plastic film etc., said back sheet shows sufficient intensity | strength, while having the outstanding moisture permeability. Therefore, the disposable diaper of the present invention using such a back sheet is not only comfortable to use, but also has a very low possibility of leaking excrement to the outside, and reliably absorbs and holds it in the absorbent body. Is possible. For this reason, excrement is less likely to adhere to the clothes or bedding of the wearer or caregiver, and it does not take time for subsequent washing or cleaning, and can reduce the burden on both the caregiver and the wearer. .

  Hereinafter, the details of the disposable diaper of the present invention will be described by taking a pants-type disposable diaper and a tape-type disposable diaper as examples. Note that the “pants-type disposable diaper” means that the corresponding side edges 2a and 6a (2b and 6b) of the front body 2 and the back body 6 are joined together, such as the disposable diaper 1A shown in FIGS. 1A to 1C. By doing this, one waist circumference opening part 10 and a pair of leg circumference opening parts 12 (12a, 12b) are formed, and it means the disposable diaper comprised by the underpants type beforehand.

  In addition, the “two-piece type” refers to the absorbent main body 14 in which the absorbent body 22, the top sheet 18, and the back sheet 20 are integrated into a pad shape like the disposable diaper 1 </ b> A shown in FIG. 1A and FIG. This means a configuration in which an exterior member 16 encapsulating a person's body is provided, and an absorbent main body 14 is disposed and fixed inside the exterior member 16.

  Further, the “tape-type disposable diaper” includes an absorbent body 22, a top sheet 18, and a back sheet 20 as in the disposable diaper 1 </ b> B shown in FIGS. 2A and 2B, and the left and right sides of the back body 6. The disposable diaper further provided with the fastening tape 11 for fixing the front body 2 and the back body 6 arrange | positioned so that it may extend from edge 6a, 6b is meant.

  Also, the “front body” is the part that covers the abdomen (front of the body) of the wearer when wearing a diaper, and the “inseam” is the part that is worn when the diaper is worn by the wearer. The part that covers the inseam of the wearer, “rear body” means a part that covers the wearer's back side (back of the body) when a diaper is worn on the wearer.

[1]: Disposable diapers:
FIG. 1 is a schematic plan view showing a state in which one embodiment of the disposable diaper of the present invention is unfolded and viewed from the top sheet side, and FIG. 1B is a cross-sectional view taken along line AA ′ of FIG. 1A. Moreover, FIG. 1C is a perspective view which shows one Embodiment of the disposable diaper of this invention. As shown in FIGS. 1A to 1C, the disposable diaper 1 </ b> A of the present embodiment includes an absorbent body 22 and a top sheet that is made of at least a part of a liquid-permeable material and covers the surface of the absorbent body 22. 18 and a back sheet 20 disposed so as to cover the back surface of the absorber 22. Also, by joining the corresponding side edges 2a, 6a (2b, 6b) of the front body 2 and the back body 6, one waist opening 10 and a pair of leg openings 12 (12a, 12b) are formed. Is formed.

[1-1] Backsheet:
As shown in FIG. 1B, the back sheet 20 is a structural member that has a sheet-like support 20a and a leak-proof coating layer 20b formed on one side of the support 20a, and has a sheet-like shape as a whole. . The back sheet 20 is disposed so as to cover the back surface of the absorber 22 (the surface located on the wearer's clothing side when the diaper is worn). Although there is no particular limitation on the arrangement method of the back sheet, for example, it may be arranged so as to match the outer shape of the diaper, but it is not always necessary to make such arrangement, and it is absorbed and held by the absorber. From the viewpoint of preventing leakage of excrement and the like, a back sheet may be disposed at least in a portion where the absorber exists.

  2B, a cover sheet 24 may be bonded to the outer surface side of the back sheet 20. This cover sheet is used to reinforce the back sheet and improve the feel (tactile feeling) of the back sheet. Examples of the material constituting the cover sheet include woven fabric and non-woven fabric. Especially, it is preferable to use the dry nonwoven fabric and wet nonwoven fabric which consist of thermoplastic resins, such as polyethylene, a polypropylene, and polyester.

[1-1-1] Support:
The support 20a constituting the back sheet 20 of the disposable diaper 1A of the present embodiment is a sheet-like member made of a material having air permeability. Since the support body 20a is comprised with the material which has air permeability, the disposable diaper 1A provided with the back sheet 20 using this support body 20a as a component is hard to be stuffy at the time of wear, and becomes comfortable to use.

The material which comprises a support body is selected from a nonwoven fabric, a woven fabric, and paper . Of these, non-woven fabrics such as dry non-woven fabrics and wet non-woven fabrics made of a thermoplastic resin such as polyethylene, polypropylene, or polyester are preferable from the viewpoints of ensuring air permeability and maintaining strength.

When configuring the support with a nonwoven fabric had a basis weight of the nonwoven fabric (mass per unit area) is preferably 10 to 150 g / ^{m 2,} and still more preferably from 15 to 40 g / ^{m 2.} When the basis weight of the nonwoven fabric is within this range, better air permeability and strength are ensured, so that the moisture permeability and strength of the back sheet provided with the support composed of the nonwoven fabric are sufficiently ensured.

[1-1-2] Leakproof coating layer:
The back sheet 20 of the disposable diaper 1A of the present embodiment is formed by forming a leak-proof coating layer 20b containing a synthetic resin on one surface of a support 20a. The leak-proof coating layer 20b is moisture permeable and liquid impermeable. That is, the backsheet 20 having the leakproof coating layer 20b formed on the surface of the support 20a having air permeability ensures good air permeability and strength by the support 20a, and the leakproof coating layer 20b. Excellent liquid impermeability and moisture permeability are ensured.

Moisture permeability of the leakage preventing coating layer is preferably ^{3000~100000g / (m 2 · 24h)} , and further preferably from ^{7000~50000g / (m 2 · 24h)} . If the moisture permeability of the leak-proof coating layer is less than 3000 g / (m ² · 24 h), it may be stuffy when worn. On the other hand, if it exceeds 100000 g / (m ² · 24 h), urine and stool odors may easily leak.

  1B shows a state in which the leak-proof coating layer 20b is formed only on one side of the support 20a, but the leak-proof coating layer is not only on one side of the support, but on both sides. It may be formed. Further, as shown in FIG. 1B, when the leak-proof coating layer 20b is formed only on one side of the support 20a, the back sheet 20 is placed so that the leak-proof coating layer 20b is on the absorber 22 side. It is preferable to arrange.

  Examples of the synthetic resin contained in the leak-proof coating layer include styrene-butadiene copolymer (SBR), acrylic-styrene copolymer, methacrylate-butadiene copolymer, acrylonitrile-butadiene copolymer, polyester, A polyurethane etc. can be mentioned. Among them, SBR is preferable because it has good water resistance and good elongation, and is difficult to cause cracks in the leak-proof coating layer due to cracking. Here, the polymerizable monomer constituting SBR is mainly composed of styrene and 1,3-butadiene, but other polymerizable monomers copolymerizable with styrene and 1,3-butadiene are used in the present invention. It is also preferable to use it within a range that does not impair the purpose. Specific examples of other polymerizable monomers include aromatic vinyl monomers, (meth) acrylic acid ester monomers, cyano group-containing ethylenically unsaturated monomers, glycidyl esters of ethylenically unsaturated acids, Examples thereof include glycidyl ethers of unsaturated alcohols and (meth) acrylamide monomers. In addition, these polymerizable monomers can be used individually or in combination of 2 or more types.

  In addition, the glass transition temperature (Tg) and the gel amount of the synthetic resin (the remaining amount of extraction with an organic solvent such as tetrahydrofuran, which is mainly composed of a polymer component having a molecular weight of several hundred thousand) mainly block the leakproof coating layer. This affects the ease of adhesion between the surface of the working layer and other components, and the film forming property of the leak-proof coating layer. When a synthetic resin having a low Tg and / or a low gel amount is used, blocking tends to occur, while film formability tends to be improved. On the other hand, when a synthetic resin having a high Tg and / or a high gel amount is used, blocking tends to be difficult, but the film formability tends to be lowered. From such a viewpoint, the Tg of the synthetic resin is usually −30 to 50 ° C., preferably −15 to 30 ° C. Moreover, the gel amount of a synthetic resin is 30-95 mass% normally, Preferably it is 60-90 mass%. In addition, what is necessary is just to determine Tg and gel amount of a synthetic resin by the balance of the film formability of a leak-proof coating layer, and blocking.

The leak-proof coating layer contains a flat pigment having an aspect ratio of 5 or more as a component other than the above synthetic resin . When such a flat pigment is contained in the leak-proof coating layer, the liquid impermeability of the leak-proof coating layer is improved while maintaining moisture permeability.

The aspect ratio of the tabular pigment is a value (D / T) obtained by dividing the average particle diameter (D) of the tabular pigment by the thickness (T) of the tabular pigment. The aspect ratio of the flat pigment is 5 or more, and preferably 10 or more. When the aspect ratio is less than 5, it is difficult to orient parallel to the coating surface of the leak-proof coating layer, and the effect of improving the liquid impermeability of the leak-proof coating layer may not be sufficiently exhibited. The thickness of the flat pigment can be measured by observation with an electron microscope.

  The flat pigment is usually a substantially flat crystalline substance having an average particle diameter of several μm or more measured by a laser diffraction method. The average particle diameter of the tabular pigment is preferably 1 to 200 μm, more preferably 3 to 100 μm, particularly preferably 5 to 50 μm, and most preferably 10 to 40 μm. If the average particle diameter is less than 1 μm, the orientation of the tabular pigment is difficult to be parallel to the surface of the support, and thus the effect of improving the liquid impermeability of the leak-proof coating layer may not be sufficiently exhibited. . On the other hand, if it exceeds 200 μm, a part of the flat pigment may protrude from the leak-proof coating layer. In addition, the average particle diameter of the tabular pigment can be measured by a microtrack laser diffraction method.

  When the flat pigment is contained in the leak-proof coating layer, if the average particle diameter of the flat pigment is too small compared to the coating thickness of the leak-proof coating layer, the flat plate is oriented parallel to the surface of the support. There is a tendency that the amount of the pigment is reduced. For this reason, it is preferable that the average particle diameter of a flat pigment is 20% or more of the coating thickness of a leak-proof coating layer.

  Specific examples of the flat pigment include phyllosilicate mineral, natural flake graphite and the like. The phyllosilicate mineral is a mineral that has a plate-like or flaky shape and a clear cleavage plane. Specific examples of the phyllosilicate mineral include mica, pyrophyllite, talc (talc), chlorite, septite chlorite, serpentine, stilpnomelane, and clay minerals. Among them, mica and talc are preferable because they are minerals with large particles at the time of production and a large amount of production. Specific examples of mica are muscovite (mascobite), sericite (sericite), phlogopite (flocopite), biotite (biotite), fluorine phlogopite (artificial mica), red mica, soda mica, vanadine mica , Illite, chin mica, paragonite, brittle mica and the like. In general, clay minerals such as kaolin are also included in the concept of tabular crystals. In particular, among kaolins, deramikaolin and the like in which the crystal layer is intentionally peeled off are preferable.

From the viewpoints of average particle diameter, aspect ratio, cost, etc., muscovite, sericite, and talc are suitable as the flat pigment. The chemical composition of muscovite is represented by “K ₂ O.3Al ₂ O ₃ .6SiO ₂ .2H ₂ O”. If the raw muscovite is classified by dry pulverization with a hammer mill or the like, muscovite with a desired particle size distribution can be obtained. Also, muscovite with a desired particle size distribution can be obtained by wet grinding such as a sand mill using glass beads as a grinding medium in water.
Note that muscovite with a high aspect ratio (for example, about 20 to 30) can be obtained by pulverizing so as not to apply excessive force or by wet pulverization while applying ultrasonic waves.

The chemical composition of sericite is similar to the chemical composition of muscovite, the ratio of SiO ₂ / Al ₂ O ₃ is slightly larger and the content of K ₂ O is smaller than that of muscovite. Since the sericite ore is finer than the muscovite ore, the average particle size of the sericite obtained by pulverization and classification is generally about 0.5 to 2 μm. For this reason, it is preferable to use those having a particle size distribution that greatly relaxes the pulverization conditions, further classifies the coarse residue portion of the general-purpose product, etc., and passes the mesh of the required size. Thereby, a sericite with a high aspect ratio (for example, about 10 to 30) can be obtained.

  Talc is a hydrate of magnesium silicate and is generally flaky particles. However, since the particle diameter of commercially available talc is about 0.1 to 3 μm, coarse talc for ceramics is used, or the same pulverization classification operation as in the case of sericite is performed, and the average particle It is preferable to obtain one having a diameter of about 10 μm. The aspect ratio of talc is smaller than that of muscovite or sericite and is about 5 to 10.

  The muscovite is preferable because the raw stone is much larger than the sericite and talc, and the particle size distribution can be easily set by pulverization and classification. On the other hand, sericite is preferable because it has a smaller raw stone than muscovite, but has good cleaving properties and the pulverized product has a flat plate shape. Talc is preferable because it is advantageous in terms of cost.

  The leak-proof coating layer constituting the back sheet of the disposable diaper of the present invention is preferably formed on at least one surface of the support with a precoat layer interposed. It is preferable to form a leakproof coating layer on the surface of the support with the precoat layer interposed, since the leakproof coating layer is formed uniformly.

  A precoat layer is a layer formed by apply | coating the foamed coating material to the nonwoven fabric surface. This paint contains an adhesive. A conventionally known adhesive may be used as the adhesive. Specific examples of the adhesive include polyacrylic acid ester, polymethacrylic acid ester, ethylene-vinyl acetate copolymer, polyester resin, polyurethane and the like. Moreover, the copolymer of these resin is used similarly. Furthermore, starch, starch derivatives, PVA, casein, CMC and the like can be used. These adhesives may exist in the form of an emulsion in the paint, or may exist in a state dissolved in a solvent in the paint.

  Moreover, you may mix | blend a white pigment with a coating material as needed. Examples of white pigments that can be blended include inorganic pigments such as calcium carbonate, magnesium carbonate, magnesium hydroxide, aluminum hydroxide, zinc hydroxide, zinc oxide, titanium dioxide, aluminum oxide, silicon dioxide, amorphous silica, and barium sulfate; styrene, Examples thereof include organic pigments composed of acrylic acid esters and the like. The white pigment content is preferably about 40 parts by mass or less with respect to 1 part by mass of the solid content of the adhesive. When the amount of the white pigment exceeds 40 parts by mass, the amount of the adhesive is relatively decreased, the adhesion between the precoat layer and the nonwoven fabric is lowered, and the precoat layer tends to fall off. Furthermore, you may mix | blend auxiliary agents, such as a lubricant, antioxidant, a ultraviolet absorber, a colored pigment, an antistatic agent, and a thickener, with a coating material as needed.

  The paint is applied to the nonwoven fabric in a foamed state. Since the foamed paint has a very low specific gravity and almost no fluidity, it is difficult to soak into the nonwoven fabric used as the base material. Therefore, even if it is applied to a porous nonwoven fabric with poor formation, it does not become impregnated by soaking as in the case of applying an unfoamed paint, and the paint does not show through. In order to foam the paint, a conventionally known foaming machine may be used. As the foaming machine, for example, a continuous foaming machine, a shaking mixer, a cake mixer or the like manufactured by Stokes of the Netherlands may be used. The foaming ratio of the paint is preferably 2 times or more. The paint viscosity after foaming is preferably in the range of 4000-200000 mPa · s, more preferably 8000-100,000 mPa · s, as measured by a BM viscometer. When the viscosity of the paint after foaming is less than 4000 mPa · s, the paint tends to penetrate into the nonwoven fabric, and the paint tends to ooze out on the back surface of the nonwoven fabric. On the other hand, if it exceeds 200,000 mPa · s, the viscosity may be too high and coating may be difficult. In order to improve the stability of the foamed state, it is preferable to add a foam stabilizer (hereinafter also referred to as “foam stabilizer”) to the coating material prior to the foaming treatment. Specific examples of the foam stabilizer include, but are not limited to, higher fatty acids, higher fatty acid modified products, higher fatty acid alkali salts, and the like. The addition amount of the foam stabilizer is usually 30 parts by mass or less, preferably 1 to 10 parts by mass with respect to 100 parts by mass of the solid content in the paint. When the amount of the foam stabilizer is more than 30 parts by mass, the stability of the paint tends to decrease.

Any conventionally known means can be adopted as means for applying the paint to the nonwoven fabric. Specifically, a coating means such as a Mayer bar, air knife, blade, slit die, lip, comma, roll coater, etc. can be employed, and further, a coating means such as a gravure or a screen can be used. It is preferable that the coating amount of a coating material is 2-50 g / m < ² > by solid content, More preferably, it is 3-30 g / m < ² >. When the coating amount is less than 2 g / m ² , the precoat layer to be formed may be incomplete, and the barrier property may be insufficient when a leak-proof coating layer is provided thereon. On the other hand, when the coating amount is more than 50 g / m ² , the flexibility of the obtained back sheet may be lowered. What is necessary is just to dry after apply | coating a coating material. In addition, you may perform calendar processes, such as a super calendar, a machine calendar, and a soft calendar, as needed.

[1-2] Top sheet:
A top sheet is a sheet | seat arrange | positioned so that the surface (surface located in a wearer's skin side at the time of mounting | wearing of a diaper) may be coat | covered. At least a part (all or a part) of the top sheet is made of a liquid-permeable material because it is necessary for the absorbent body arranged on the back surface side to absorb the wearer's urine and the like. Usually, at least near the surface of the absorber, it is made of a liquid-permeable material that can permeate the wearer's urine and body fluid. As long as at least a part is made of the liquid permeable material, the entire top sheet is not necessarily made of the liquid permeable material.

  Examples of the liquid permeable material constituting the top sheet include a woven fabric, a nonwoven fabric, and a porous film. Especially, it is preferable to use what performed the hydrophilic treatment to the nonwoven fabric which consists of thermoplastic resins, such as a polypropylene, polyethylene, polyester, nylon. There is no restriction | limiting in particular also about the kind of nonwoven fabric, The conventionally well-known nonwoven fabric manufactured by various manufacturing methods, such as air through (card hot air), card | curd embossing, and a spun bond, can be used suitably.

  The top sheet may be composed of a single sheet material, but may be composed of a plurality of sheet materials. For example, in a tape-type disposable diaper, a form in which a top sheet disposed on an upper surface portion of an absorbent body and a top sheet disposed on a side flap portion are constituted by different sheets is often used. For example, the absorbent article 1B shown in FIGS. 2A and 2B is a tape-type disposable diaper. A topsheet 18 made of a liquid-permeable material is disposed at the center in the width direction of the diaper, and the side flap 9 portion of the diaper is disposed. Is an example in which a side sheet 19 made of a breathable water-repellent material exhibiting resistance to liquid permeation is disposed. The breathable water-repellent material constituting the side sheet may be a non-woven fabric produced by a method such as card embossing or spunbond, but a non-woven fabric sheet such as SMS or SMMS having a high waterproof property is more preferable.

[1-3] Absorber:
The absorber is a member for absorbing and holding the wearer's urine. The absorber is made of an absorbent material because it needs to absorb and retain the wearer's urine and body fluid.

  Examples of the absorbent material constituting the absorber include conventionally known absorbent materials usually used for disposable diapers and other absorbent articles, such as fluff pulp, super absorbent polymer (Super Absorbent Polymer; hereinafter referred to as “SAP”). And a hydrophilic sheet. Use fluff pulp made of wood pulp or non-wood pulp defibrated, SAP as sodium polyacrylate, hydrophilic sheet as tissue paper, absorbent paper, hydrophilized non-woven fabric Is preferred.

  These absorbent materials are usually used as a single-layer or multi-layer mat. Under the present circumstances, 1 type may be used independently among the said absorptive materials, and 2 or more types may be used together. Especially, what combined about 10-500 mass parts SAP with respect to 100 mass parts of fluff pulp is preferable. At this time, the SAP may be uniformly mixed in each mat of fluff pulp, or may be arranged in layers between the layers of the multilayer fluff pulp.

  In addition, a sheet (second sheet) for diffusing liquid such as urine and body fluid may be incidentally disposed on the surface side of the absorber (for example, between the absorber and the top sheet). . When this second sheet is attached, due to the wearer's posture, etc., even when the space on the back side of the top sheet is not sufficiently formed, the absorption rate of urine, body fluid, etc. is difficult to decrease, and the absorption rate decreases. It is possible to prevent leakage of urine and body fluids.

  Examples of the material constituting the second sheet include hydrophilic and liquid-permeable materials such as woven fabric, non-woven fabric, porous plastic, and fluff pulp. Examples of these constituent materials include polypropylene, polyethylene, polyester, rayon, acetate, or composite fibers thereof, and pulp. As the pulp, crimped fibers such as curly cellulose fibers can be suitably used.

  Although there is no restriction | limiting in particular about the shape of an absorber, The shape used in the conventional disposable diaper and other absorbent articles, for example, a rectangular shape, an hourglass type, a gourd type, a T shape etc. can be mentioned.

  The entire absorbent body is preferably encapsulated by a hydrophilic sheet. Such a configuration has an advantage that SAP can be prevented from leaking from the absorber and shape stability can be imparted to the absorber.

  Usually, the absorber is interposed between the top sheet and the back sheet by being sandwiched between the top sheet and the back sheet and sealing the peripheral edge thereof. Therefore, the flap part in which the absorber is not interposed is formed between the top sheet and the back sheet at the peripheral part of the absorber. The absorbent body may be interposed at least in the crotch region, and the absorbent body may extend to the front body and the back body.

[1-4] Solid gathering:
The disposable diaper of the present invention is preferably made of a water-repellent sheet and includes at least a pair of three-dimensional gathers arranged on both sides of the absorbent body.

  The three-dimensional gather is a member for preventing side leakage of the urine excreted by the wearer, and is a leak-proof wall configured to stand up three-dimensionally. By forming such a three-dimensional gather, the three-dimensional gather serves as a leak-proof wall, and leakage (so-called “lateral leakage”) from leg openings, side edges and the like of the disposable diaper can be effectively prevented.

  The structure of a three-dimensional gather can employ | adopt the structure used for the conventional disposable diaper and other absorbent articles. For example, like a disposable diaper 1A shown in FIG. 1B and a disposable diaper 1B shown in FIG. 2B, an elastic material (three-dimensional gather elastic material 36) is sandwiched and fixed between layers of the water-repellent sheet 32, and the three-dimensional gather elastic material 36 is fixed. A material in which a gather is formed by a contraction force can be suitably used. In these examples, the three-dimensional gather stretchable material 36 is sandwiched and fixed to the folded portion of the water-repellent sheet 32.

  The three-dimensional gather may be separately provided with a water-repellent sheet for three-dimensional gather as described above, or may be formed by a part of the sheet material constituting the diaper. For example, the disposable diaper 1B shown in FIG. 2B is an example in which the three-dimensional gathers 26a and 26b are formed by a part of the water-repellent sheet 32 constituting the side sheet 19. The water-repellent sheet may be a nonwoven fabric produced by a production method such as card embossing or spunbonding, but a nonwoven fabric sheet such as SMS or SMMS having a high waterproof property is more preferable.

[1-5] Fastening tape:
The disposable diaper of this invention may be provided with the fastening tape for fixing the front body and the back body arrange | positioned so that it may extend from each right and left side edge of a back body. That is, the disposable diaper of the present invention includes a so-called tape-type disposable diaper.

  The fastening member of the fastening tape may be an adhesive fastener that is fixed by an adhesive, but a mechanical fastener (planar fastener) that is fixed by mechanical coupling is preferably used. In addition to high fastening force, the mechanical fastener has an advantage that the fastening force does not decrease even when the detachment is performed a plurality of times.

  For example, the disposable diaper 1B shown in FIG. 2A is an example in which a mechanical fastener 46 is used as a fastening member. A hook material 46 a is attached near the tip of the fastening tape 11, while a front patch 13 made of a loop material 46 b is attached to the front body 2, and the fastening tape 11 is attached to the front patch 13. It is comprised so that it can stop.

  The number of fastening tapes is not particularly limited, and an appropriate number of fastening tapes may be attached according to the dimensions of the wearer's body shape (specifically, around the waist, around the legs, etc.). In general, a pair of disposable diapers for infants (one each on the left and right) is attached, and a pair of disposable diapers for adults (two on the left and two on the left) are attached.

[1-6] Various elastic materials:
In the disposable diaper of the present invention, it is preferable to arrange the elastic material around the legs and arrange the elastic material around the waist.

  The leg circumference elastic material is an elastic material arranged along the leg circumference opening. By arranging the leg-stretchable material, a gather (leg gather) rich in stretchability can be formed in the leg-surrounding opening. Therefore, it is difficult to form a gap around the leg, and urine leakage from the opening around the leg can be effectively prevented.

  For example, a disposable diaper 1A shown in FIG. 1A is a pants-type disposable diaper, and is an example in which leg gathers are arranged in a curved manner along the curve of the leg circumference opening of the diaper to form a leg gather. On the other hand, the disposable diaper 1B shown in FIG. 2A is a tape-type disposable diaper, and is an example in which leg gathers are formed by linearly arranging three leg-around elastic members 40 along the longitudinal direction of the diaper. The leg-surrounding elastic member 40 is made of thread rubber or flat rubber.

  As for the leg periphery elastic material, it is preferable that the leg periphery elastic material 40 is formed in the part outside the standing line of the solid gather 26 like the disposable diaper 1B shown to FIG. 2A, for example. With such a configuration, it is possible to improve the wearing feeling and wearing feeling of the crotch part while ensuring a sufficient leakage preventing effect of the three-dimensional gather.

  The waist elastic material is an elastic material arranged along the waist opening. By arranging the elastic material around the waist, a gather (waist gather) rich in elasticity can be formed in the waist opening. This waist gather makes it difficult for gaps to be formed around the waist, preventing urine leakage from around the waist, and improving the fit of the diaper to the wearer, thereby preventing the diaper from falling down.

  For example, the disposable diaper 1A shown in FIGS. 1A and 1B is an example in which a plurality of waist elastic members 42 are arranged along the opening end of the waist opening of the diaper. On the other hand, the disposable diaper 1B shown in FIG. 2A is an example in which a band-like waist elastic member 42 is disposed along the edge of the back body 6 of the diaper. The belt-like waist elastic member 42 is made of an elastic foam such as urethane foam. In the illustrated example, the waist elastic member 42 is disposed only on the back body (back side), but the waist elastic material may be disposed on the front body (abdominal side).

  An abdominal circumference elastic material is an elastic material arrange | positioned in the part (namely, part equivalent to a wearer's abdominal circumference) between a waist circumference opening part and a leg circumference opening part. By arranging the elastic material around the abdomen, it is possible to form a highly elastic tammy gather around the abdomen of the wearer. This Tammy Gather, together with West Gather, can make the diaper fit and anti-slip effect even better.

  A disposable diaper 1A shown in FIG. 1B includes a plurality of disposable diapers that surround the wearer's belly at a portion between the waist opening and the leg opening (that is, a portion corresponding to the wearer's belly). This is an example in which an abdominal circumference elastic member 44 is arranged.

  For these stretchable materials, after considering the degree of shrinkage of gathers, etc., the constituent material, the elongation rate of the material, the stretched state at the time of fixing, etc. may be determined. As an elastic material, the elastic material which has been used with the conventional disposable diaper can be used conveniently. Specific examples include elastic rubber, elastic film, elastic foam (urethane foam, etc.), etc. in addition to natural rubber flat rubber and synthetic rubber (urethane rubber, etc.) elastic thread. it can.

  The stretchable material is preferably fixed in the stretched state in order to exert a sufficient stretch force. For example, when the elastic material is a flat rubber made of natural rubber or a thread rubber made of an elastic thread of synthetic rubber, it is preferably fixed in an extended state of 120 to 400%, and fixed in an extended state of 200 to 300%. More preferably. By fixing in the extended state in such a range, it is possible to apply a sufficient expansion / contraction force without applying an excessive tightening force to the wearer.

  The stretchable material as described above is fixed to other constituent members of the diaper by an adhesive or other means. The fixing method may be, for example, adhesion using a hot melt adhesive or other highly fluid adhesive, or may be welding by heat such as heat sealing or ultrasonic waves.

[2] Disposable diaper manufacturing method:
Next, the manufacturing method of the disposable diaper of the present invention will be described by taking as an example the case of manufacturing the disposable diaper 1A shown in FIGS. 1A to 1C.

[2-1] Production of back sheet:
The back sheet 20 can be manufactured, for example, by coating a coating material containing a synthetic resin on the surface of the support 20a to form a leak-proof coating layer 20b.

As the coating material, a synthetic resin emulsion or a synthetic resin solution solubilized by mixing with alkaline water or a solvent can be used. In order to form the leak-proof coating layer 20b containing a flat pigment , a synthetic resin emulsion and a flat pigment dispersed in water or an organic solvent such as toluene or methyl ethyl ketone (MEK) are mixed. The obtained coating material may be used, or a coating material obtained by adding a flat pigment to a synthetic resin solution may be used. In addition, you may add a thickener, a dispersing agent, an antifoamer, surfactant, a tint modifier, an inorganic pigment, an organic pigment etc. as needed.

The mixing ratio of the flat pigment and the synthetic resin is preferably in the range of 30/70 to 70/30 in terms of mass ratio. When the blending ratio of the flat pigment and the synthetic resin is less than 30/70 by mass ratio, the effect produced by blending the flat pigment may be insufficient. On the other hand, when the mixing ratio of the flat pigment and the synthetic resin is more than 70/30 by mass ratio, there are many voids between the flat pigment and the synthetic resin contained in the leakage-proof coating layer formed, The liquid impermeability of the leak-proof coating layer may decrease.

The coating amount of the leak-proof coating layer (the coating amount of the coating material for forming the leak-proof coating layer) is preferably 0.5 to 50 g / m ^2, and preferably 5 to 30 g / m ^2. More preferably. If the coating amount is less than 0.5 g / m ² , the liquid impermeability of the formed leakage-proof coating layer may be lowered. On the other hand, if it exceeds 50 g / m ² , the moisture permeability of the leak-proof coating layer to be formed may be lowered.

The coating equipment for coating the coating material on the surface of the support 20a is not particularly limited . However, a coating method that uses a blade coater , a bar coater, an air knife coater, or the like to scrape the coated surface is preferable because it tends to promote the orientation of the flat pigment.

[2-2] Production of absorbent main body:
The absorber 22 wrapped in the hydrophilic sheet is disposed on the upper surface of the back sheet 20 manufactured as described above, and the top sheet 18 is disposed on the upper surface. Subsequently, the absorptive main body 14 can be obtained by sealing the periphery of the absorbent body 22 so as to be sandwiched between the top sheet 18 and the back sheet 20.

[2-3] Production of exterior member:
Two nonwoven sheets serving as the exterior member 16 are prepared, and an elastic material 42 around the waist, an elastic material 44 around the abdomen, and an elastic material 40 around the legs are arranged on the upper surface of one of the nonwoven sheets (outer sheet 16b). , Glue and fix. Then, another non-woven sheet (inner sheet 16a) is laminated and fixed on the upper surface, thereby expanding / contracting the waist elastic member 42, the belly elastic member 44 and the leg elastic member between the two nonwoven sheets. The exterior member 16 in which the material 40 is interposed can be obtained.

[2-4] Manufacture of disposable diapers:
The absorbent main body 14 is disposed and fixed near the crotch part of the exterior member 16. Next, the absorbent body 14 is turned inside, and the front body 2 and the back body 6 are folded in two so that the front body 2 and the back body 6 are matched, and the front body 2 and the back body 6 are joined by means such as heat sealing to form the joint 8. By doing, the disposable diaper 1A shown to FIG. 1A-FIG. 1C can be manufactured.

  The series of steps as described above can be continuously performed by mechanical means. For example, by adopting a method / apparatus such as continuously feeding a long sheet material or stretchable material from a roller, it becomes possible to continuously manufacture disposable diapers, which contributes to an improvement in productivity.

  The disposable diaper of the present invention can be suitably used as a disposable diaper for infants or adults such as elderly people and persons with disabilities who need care.

It is a schematic plan view which shows the state which unfolded and viewed one Embodiment of the disposable diaper of this invention from the top sheet side. It is A-A 'sectional drawing of FIG. 1A. It is a perspective view showing one embodiment of the disposable diaper of the present invention. It is a schematic plan view which shows the state which looked at the other embodiment of the disposable diaper of this invention from the top sheet side. It is A-A 'sectional drawing of FIG. 1A.

Explanation of symbols

1A, 1B: disposable diapers, 2: front body, 2a, 2b: side edge, 4: crotch, 6: back body, 6a, 6b: side edge, 8: joint, 9: side flap, 10: waist circumference Opening, 11: Fastening tape, 12, 12a, 12b: Opening around leg, 13: Front patch, 14: Absorbent body, 16: Exterior member, 16a: Outer sheet, 16b: Inner sheet, 18: Top sheet , 19: side sheet, 20: back sheet, 20a: support, 20b: leak-proof coating layer, 22: absorber, 24: cover sheet, 26, 26a, 26b: three-dimensional gather, 32: water repellent sheet, 36 : Three-dimensional gather elastic material, 40: Elastic material around leg, 42: Elastic material around waist, 44: Elastic material around belly, 46: Mechanical fastener, 46a: Hook material, 46b: Loop material

Claims (5)

An absorbent body, a top sheet that is at least partially made of a liquid-permeable material and disposed to cover the surface of the absorbent body, and a back sheet disposed to cover the back surface of the absorbent body. Prepared,
The back sheet is a sheet-like support made of a breathable material selected from a nonwoven fabric, a woven fabric, or paper , and a synthetic resin and an aspect ratio of 5 or more formed on at least one side of the support . A disposable diaper having a leak-proof coating layer containing a flat pigment .   The disposable diaper according to claim 1, wherein the synthetic resin is a styrene-butadiene copolymer. The coating amount of the anti-Monuri coating layer is, the disposable diaper according to claim 1 or 2 is 0.5 to 50 g / ^{m 2.} The disposable diaper according to any one of claims 1 to 3, wherein a moisture permeability of the leak-proof coating layer is 3000 to 100000 g / (m ² · 24 h). The anti Monuri coating layer is at least on one side, the disposable diaper according to any one of claims 1-4, which is formed while interposing the precoat layer of the support.

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