JPH1158638A - Composite sheet for throwaway diaper and throwaway diaper using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a liquid from transmitting and further contrive to improve the bond strength of a waist measure side part at manufacturing and the productivity of a diaper by a method wherein a laminate sheet consisting of a polypropylene non- woven fabric sheet, a resin film and a non-woven fabric under the condition that the resin film having a specified composition is used as the liquid impermeable film. SOLUTION: In a composite sheet, which is formed by pilling up a laminate sheet consisting of a resin film 3 and a non-woven fabric layer 2 and a polyprolyne non- woven fabric sheet 4, the non-woven fabric layer 2 in the laminate sheet is piled up so as to face outside. In addition, the resin film 3 is made of a thermoplastic resin composition consisting of 80-20 wt.%, preferably 60-40 wt.% of polypropylene resin and 20-80 wt.%, preferably 40-60 wt.% of polyethylene resin. As a result, the transmittance of a liquid can be prevented from developing under the condition that a cloth-like feeling and the flexibility of a sheet are maintained. At the same time, even in the case that the sheet is shaped into a pulling over type throwaway diaper, the bond strength of a waist measure side part at manufacturing and the productivity of the diaper can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated sheet used for a disposable diaper and a disposable diaper using the same, and more particularly, to a disposable diaper formed by laminating at least a specific laminated sheet and a nonwoven fabric sheet. Sheets and disposable diapers.

[0002]

2. Description of the Related Art Conventionally, as a disposable diaper for infants or adults, an adhesive tape for attachment and detachment is attached to an hourglass-shaped flat sheet. A so-called fastening type in which a front part and a rear part are connected to each other is used. However, in this type of disposable diaper, there is a risk that the adhesive tape portion may be loosened, stretched or detached without knowing, and urine may leak out during urination. Also, unlike underwear that wears like pants, it only stops on both sides of the waist, so it does not always fit perfectly from the thigh to the crotch part, especially for infants who have grown to some extent, If the activity is also active,
It was displaced by the movement, and the sense of security of wearing it was not always sufficient.

[0003] Under these circumstances, a disposable diaper that can be worn like pants has been desired. However, in the manufacture of a disposable diaper that is worn, the manufacturing process is more complicated than that of the conventional type. There was a disadvantage that it would. In both types, the top sheet, that is, the sheet on the side that the skin touches when worn, is made of a liquid-permeable material, and the back sheet, that is, the one that is outside when worn, is made of a liquid-impermeable material. A single sheet or a laminated sheet of a sheet made of a liquid impermeable material and a nonwoven fabric sheet is used, and the same is true in that a composite flat sheet in which such a top sheet and a back sheet are stacked is used. However, while the so-called fastening type is an hourglass-shaped flat sheet as it is, in the case of a disposable diaper to be worn, the hourglass-shaped flat sheet is placed on the top sheet side at the portion where it hits the crotch. It is necessary to fold the inside of the waist and join the waist portion while leaving a portion through which the foot passes to form a pants-like shape.

[0004] In this process, the top sheet side which is bent and comes into contact with each other, that is, the front body and the back body are joined together at the side to form a pants-like shape. It is in a double overlapped state, and the double overlapped portion is heated and pressed. Conventionally, as a material for disposable diapers, a polypropylene nonwoven fabric is used for a top sheet because of its good texture, and a backsheet is a laminated sheet of a low-density polyethylene resin film and a nonwoven fabric, and the resin film is interposed. As described above, a composite sheet in which the top sheet and the back sheet are overlapped is used. In this case, the seal interface to be thermally fused is the same between the polypropylene nonwoven fabrics. Originally, a nonwoven fabric having a small basis weight is used for this nonwoven fabric in order to quickly absorb urine and the like. For this reason, it has been pointed out that the seal strength at the heat-sealed interface cannot be increased and the seal surface is broken. In order to solve such a drawback, the low-density polyethylene resin film layer is not present only in the joint portion, and only two layers of a nonwoven fabric layer as a top sheet and a nonwoven fabric layer as a back sheet are formed. Has been adopted in order to complement the small basis weight by applying heat fusion to impart strength.
For this reason, there is a problem in the process that the layered structure of the adhesive portion must be two layers except for the low-density polyethylene resin film layer.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made from the above viewpoint, and satisfies the basic performance of a diaper that prevents liquid permeation while maintaining a cloth-like feel and flexibility.
In addition, even in the case of shaping into a disposable diaper of a wearable type, a disposable diaper sheet having good bonding processing suitability of the waist side portion at the time of its production, excellent bonding strength and productivity, and a disposable diaper using the same. It is intended to provide diapers.

[0006]

Means for Solving the Problems As a result of extensive studies, the present inventors have found that a polypropylene non-woven fabric sheet, a resin non-woven fabric sheet and a polypropylene non-woven fabric sheet can be used as a liquid impermeable film by using a resin film having a specific composition. It has been found that the above object can be achieved by forming a laminated sheet composed of The present invention has been completed based on such findings.

That is, the present invention provides the following disposable diaper sheet and a disposable diaper using the sheet. At least a composite sheet obtained by laminating a laminated sheet (1) of a resin film and a nonwoven fabric and a nonwoven fabric sheet (2) made of polypropylene such that the nonwoven fabric layer of the laminated sheet (1) is located outside. Wherein the resin film layer of the laminated sheet (1) is made of a resin composition in which a polypropylene resin is 80 to 20% by weight and a polyethylene resin is 20 to 80% by weight. Composite sheet.

[0008] A disposable diaper using the disposable diaper sheet described above, wherein the polypropylene nonwoven sheet (2) is a top sheet, and the nonwoven layer of the laminated sheet (1) is outside and the backsheet is a backsheet. .

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below. 1. Contents of each sheet constituting the composite sheet (1) Laminated sheet of resin film and non-woven fabric (1) Resin film In a disposable diaper, the resin film serves as a liquid-impermeable film to prevent urine and the like from leaking outside. It will fulfill its role.

The present invention is characterized by the composition of the resin composition constituting the resin film. That is, the resin film contains 80 to 20% by weight of a polypropylene resin,
Preferably 60 to 40% by weight and 2% polyethylene resin
It is characterized by being composed of a thermoplastic resin composition of 0 to 80% by weight, preferably 40 to 60% by weight. When the content of the polypropylene resin exceeds 80% by weight, the resin may be lacking in softness. On the other hand, if the content is less than 20% by weight, there is a possibility that the joining strength of the sealing portion is insufficient and the strength stability is lacking. Polypropylene resin has a density of 0.930 g / cm ^{3 in} terms of softness.
The following is preferred. In addition, the polypropylene resin here is a polypropylene homopolymer, a polypropylene copolymer containing propylene as a main component, or a polypropylene homopolymer or a polypropylene copolymer and various additives added within a range that does not impair the object of the present invention. This is a concept that also includes a composition with a third component such as, for example, but in particular, random polypropylene is preferably used from the viewpoint of compatibility with polyethylene. On the other hand, the polyethylene resin also has a density of 0.930 g / cm ³ or less from the viewpoint of softness, and further 0.99 g / cm ^3.
It is preferably ³ or less. Further, the polyethylene resin here is a so-called high-density polyethylene (HDP).
E) and linear low density polyethylene (LLDP)
E) may be used. Further, LLDPE may be a polymer obtained using a so-called metallocene catalyst.

Other than the above, the thermoplastic resin composition
If necessary, a pigment, a heat stabilizer, a deodorant, an antibacterial agent and the like may be added. About the manufacturing method of the resin film,
There is no particular limitation, and a known extrusion molding method such as an inflation molding method or a T-die molding may be used. The thickness of the resin film layer is 8 to 50 μm, preferably 1 to 50 μm.
0 to 35 μm. If it is less than 8 μm, pinholes are likely to occur and stable liquid impermeability may not be obtained. If it is more than 50 μm, it may be too thick to obtain cloth-like softness as a whole.

Nonwoven fabric The nonwoven fabric constituting the laminated sheet (1) of the present invention includes not only a product nonwoven fabric which has undergone a bonding process such as heat bonding or bonding with an adhesive, but also a so-called non-woven fabric which has not undergone these bonding processes. Nonwoven webs are also included. The fiber used is not particularly limited, but may be polypropylene, polyethylene, polyethylene terephthalate (P
ET), polyurethane, cellulosic fibers and composite fibers thereof are preferably used. Among them, polypropylene is more preferably used. There is also no particular limitation on the method for producing the nonwoven fabric, and it is appropriately selected from the methods that provide flexibility and bulkiness. It can be manufactured by a known method such as spun bonding, spun lace, hot air card, hot embossed card, and melt blow. Among them, the following method is preferably used from the viewpoint of securing air permeability and softness. For example, the spun bond method is preferable because it can be manufactured in one step, and a bulky and soft material having excellent hydrophobicity is easily obtained. In addition, composite fibers of the spun bond method and the melt blow method, specifically, composite fibers of the spun bond method / melt blow method / spun bond method, and composite fibers of the spun bond method / melt blow method, It has excellent performance that there is no unevenness in weight, the appearance is good, and the excrement is highly concealable. Furthermore,
A conjugate short fiber (for example, polyethylene and polyethylene terephthalate) formed into a sheet using a card machine and heat-sealed with hot air, hot embossing, or the like is also preferable because it is soft and has high concealability of excrement. Such a conjugate short fiber includes a side-by-side type and a core-sheath type.

The basis weight of the nonwoven fabric is not particularly limited, but is 10 to 30 g / m ² , preferably 15 to ²⁰ g / m ² .
² If it exceeds 30 g / m ² , the nonwoven fabric itself may become thick and lack softness.
If it is less than 0 g / m ² , there is a problem that it is difficult to obtain industrially stable quality. Manufacturing method of laminated sheet It can be manufactured by a known extrusion lamination, for example, a method in which a resin is melt-extruded onto a nonwoven fabric base material, and a nonwoven fabric base material is simultaneously fed from a sandwich feeding portion through the lamination to laminate. Among them, extrusion lamination in which a resin film is directly melt-extruded onto a nonwoven fabric sheet and joined is preferable in terms of process and economy. In joining, partial joining using an uneven roll or the like is preferably used from the viewpoint of the softness of the obtained laminated sheet. (2) Polypropylene nonwoven fabric sheet The nonwoven fabric also includes product nonwoven fabrics and nonwoven webs that have undergone a bonding step such as heat bonding or bonding with an adhesive, similarly to the above nonwoven fabrics. Polypropylene is used because of its good texture. There is no particular limitation on the method of manufacturing the nonwoven fabric,
The method is appropriately selected from methods that can provide flexibility and bulkiness.
It can be manufactured by a known method such as spun bonding, spun lace, hot air card, hot embossed card, and melt blow. Among them, the following method is preferably used from the viewpoint of securing air permeability and softness. For example, the spun bond method is preferable because it can be manufactured in one step, and a bulky and soft material having excellent hydrophobicity is easily obtained. In addition, composite fibers of the spun bond method and the melt blow method, specifically, composite fibers of the spun bond method / melt blow method / spun bond method, and composite fibers of the spun bond method / melt blow method, It has excellent performance that there is no unevenness in weight, the appearance is good, and the excrement is highly concealable. Furthermore, a composite staple fiber formed into a sheet using a card machine and heat-sealed with hot air or hot embossing or the like is also preferable because of its softness and high excrement concealing property. Such a conjugate short fiber includes a side-by-side type and a core-sheath type.

The basis weight of the nonwoven fabric is not particularly limited, but is 10 to 30 g / m ² , preferably 15 to ²⁰ g / m ² .
² If it exceeds 30 g / m ² , the nonwoven fabric itself may become thick and lack softness.
If it is less than 0 g / m ² , there is a problem that it is difficult to obtain industrially stable quality. 2. Composite Sheet for Disposable Diapers The composite sheet according to the present invention is required to have at least two kinds of sheets, a laminated sheet (1) of a resin film and a nonwoven fabric, and a nonwoven fabric sheet (2) made of polypropylene laminated. If necessary, between the laminated sheet (1) and the nonwoven fabric sheet made of polypropylene (2),
A liquid absorbing sheet or the like may be partially present. In a disposable diaper, the polypropylene nonwoven fabric sheet (2) becomes a top sheet, that is, a sheet on the side to be touched by the skin at the time of wearing, and the laminated sheet (1) comes to the outside at the time of wearing, because of its good texture. It becomes a sheet. Further, as the sheet that is outside at the time of mounting, the non-woven fabric that is not in contact with the wearer's skin but is in contact with the hand of another person is a good nonwoven fabric in the laminated sheet (1) in terms of texture. It must be superimposed so that it is on the outside. That is, in the back sheet, the resin film layer is inside and the nonwoven fabric layer is outside.

When the composite sheet is used for a disposable diaper, the above sheets are overlapped in a predetermined manner, cut into a predetermined shape, and the cut portion is bonded by heat fusion or the like. 3. Disposable diaper A disposable diaper using the composite sheet for disposable diapers. The composite sheet for disposable diapers according to the present invention can be applied to both fastening and disposable types of disposable diapers, but is extremely advantageous particularly when producing disposable diapers of a wearable type. . (1) Manufacturing method In the case of the fastening type, it can be manufactured by attaching and detaching adhesive tape to a flat sheet obtained by cutting the composite sheet into an hourglass shape.

[0016] The type of disposable diaper to be worn is usually
The flat composite sheet obtained by cutting into an hourglass shape is folded with the top sheet side inward at the part that hits the crotch part, and the waist part is joined except for the part where the foot passes, and shaped into pants Can be manufactured. In this case, the top sheet sides that have been folded and encountered, ie,
As shown in FIG. 1, the front body and the back body are formed into a pants-like shape by bonding them together with a so-called palm joint. The joining portion is in a state in which the flat composite sheet is doubly overlapped, and the doubly overlapped portion can be heat-pressed with a heating roll or the like so as to be bonded together.

In particular, a liquid-absorbent sheet is provided as an intermediate sheet between the laminated sheet (1) and the nonwoven fabric sheet (2) made of polypropylene in a portion where absorption of urine or the like is required, such as a crotch portion. It is preferable to use a sheet composed of the three types of sheets thus obtained, and to use the laminated sheet (1) and the nonwoven sheet made of polypropylene (2) for the other portions. In this case, the composite sheet composed of the two types of sheets, the laminated sheet (1) and the nonwoven fabric sheet (2) made of polypropylene, overlaps the portion to be attached to the palm, which is convenient for thermocompression bonding.

The liquid-absorbing sheet is not particularly limited, but a sheet obtained by wrapping pulp, a water-absorbing polymer, or the like with a tissue or the like is used. In the portion where the liquid-absorbing sheet is interposed, the liquid-absorbing sheet is bonded to the back sheet by a method such as spot bonding.

[0019]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Evaluation of the properties of the obtained disposable diaper,
The test was performed in the following manner. Seal strength: Using an Instron tensile tester as a tester, a test piece having a width of 15 mm was pulled at a tensile speed of 200 mm.
/ Min until pulled. The maximum value at the time of breaking was defined as "seal strength".

Sealability: From the results of the above-mentioned seal strength test, sealability was evaluated in three stages. ：: Good heat sealability. Sufficient sealing strength is obtained, and the sealing temperature range is wide. Δ: Seal strength was obtained at a certain temperature or higher, but the seal temperature range was narrow.

×: No seal strength was obtained, and there was a problem in practicality. Softness: Sensory evaluation was performed based on the feel of the hand. It was evaluated on a three-point scale whether it was soft and close to a cloth. ：: Feels soft. △: I feel normal.

×: Feels hard. Example 1 As a resin film, polypropylene resin (PP) (manufactured by Idemitsu Petrochemical Co., Ltd.)
Product name "Idemitsu Polypro F-794N1" (Density 0.8
90 g / cm ³ ) and 60% by weight of linear low density polyethylene (LLDPE) (manufactured by Dow Chemical Company, trade name “Affinity EG8200” (density 0.870 g / cm ³ )
³ ) While melt extruding a resin composition comprising 40% by weight with a T-die molding machine, a nonwoven fabric sheet (polypropylene spunbond (PP spunbond) nonwoven fabric, manufactured by Idemitsu Petrochemical Co., Ltd .; trade name "Stratec RW2020" (basis weight)
20 g / m ² ), roll-pressed and joined to obtain a laminated sheet. Resin temperature 250 ° C, film thickness 15
μm, the throughput was 23 kg / h, and the take-off speed was 80 m / min.

Next, the above-mentioned laminated sheet of a resin film and a nonwoven fabric, and a polypropylene nonwoven fabric sheet (polypropylene spunbond (PP spunbond) nonwoven fabric, manufactured by Idemitsu Petrochemical Co., Ltd .; trade name: “Stratec RW2020”)
(A basis weight of 20 g / m ² ) and a resin film was interposed therebetween to obtain a composite sheet. Next, the composite sheet obtained above was cut in half, assuming that the disposable diaper was attached to the side seal, and the two pieces obtained were joined to the polypropylene nonwoven fabric side, which should correspond to the top sheet, as shown in FIG. As an interface, bonding was performed by pressing with a heating roll. The crimping temperature was 135 to 150 ° C., and crimping was performed at a linear pressure of 35 kg / cm for 5 seconds. Table 1 shows the results.

[0024]

[Table 1]

Example 2 In Example 1, linear polyethylene (LLDP) was used as the polyethylene resin.
E) (manufactured by Dow Chemical Company, trade name "Affinity E
G8200 ") in the same manner as in Example 1 except that linear low density polyethylene (LLDPE) (manufactured by Idemitsu Petrochemical Co., Ltd., trade name" Moretech-0438CL "(density 0.918 g / cm ³ )) was used instead. The results are shown in Table 1. Example 3 In Example 1, the polypropylene resin 6 was used.
0% by weight and linear low density polyethylene (LLDPE) 4
While the resin composition consisting of 0% by weight is melt-extruded with a T-die molding machine, the same resin composition is formed into a film by a T-die molding machine instead of being overlapped with a nonwoven fabric sheet and roll-bonded and joined. Example 1 was repeated except that this film was bonded to a nonwoven fabric sheet by thermocompression bonding using a heat laminating machine. Table 1 shows the results. [Comparative Example 1] In Example 1, the polypropylene resin 6 was used.
0% by weight and linear low density polyethylene (LLDPE) 4
Instead of the resin composition consisting of 0% by weight, linear low-density polyethylene (LLDPE) (trade name “Moretech-0438CL” manufactured by Idemitsu Petrochemical Co., Ltd. (density 0.918 g /
cm ³ ) The procedure was the same as in Example 1 except that only 100% by weight was used. Table 1 shows the results. [Comparative Example 2] In Example 1, the polypropylene resin 6 was used.
0% by weight and linear low density polyethylene (LLDPE) 4
Instead of the resin composition consisting of 0% by weight, polypropylene resin (PP) (trade name "Idemitsu Polypro F-794N1" manufactured by Idemitsu Petrochemical Co., Ltd. (density 0.890 g / cm ³ ))
The same procedure was performed as in Example 1 except that only 100% by weight was used. Table 1 shows the results. [Comparative Example 3] In Example 1, the polypropylene resin 6 was used.
0% by weight and linear low density polyethylene (LLDPE) 4
Instead of the resin film composed of 0% by weight of the resin composition, a linear low density polyethylene (LLDPE) film (trade name "Idemitsu Polyethylene-L0" manufactured by Idemitsu Petrochemical Co., Ltd.)
314L ”(density 0.920 g / cm ³ ) with a thickness of 25μ
m)), except that a laminated sheet obtained by bonding the same nonwoven fabric sheet and a hot melt adhesive as in Example 1 was used. Table 1 shows the results. [Comparative Example 4] The procedure of Example 1 was repeated, except that the resin film was not used, and only the nonwoven fabric and the polypropylene nonwoven fabric were heat-sealed. Table 1 shows the results
Shown in

[0026]

As described above, the disposable diaper sheet of the present invention satisfies the basic performance of a diaper that prevents the permeation of a liquid while maintaining the feel and flexibility of a cloth, and is shaped into a disposable diaper that can be worn. Also in this case, the bonding workability of the waist side portion at the time of manufacturing is good, and the bonding strength and productivity are excellent.

[Brief description of the drawings]

FIG. 1 is a schematic view of a disposable diaper of a wearable type in which a front body and a back body are attached to a palm at a waist side.

FIG. 2 is a schematic view of a bonded portion pressed by a heating roll with a polypropylene nonwoven fabric side corresponding to a top sheet as a bonding interface.

[Explanation of symbols]

 1: Joint between front and back body 2: Non-woven fabric layer in back sheet 3: Resin film layer in back sheet 4: Top sheet (polypropylene non-woven fabric) 5: Seal interface

Claims (2)

[Claims] 1. A composite sheet obtained by laminating at least a laminated sheet (1) of a resin film and a nonwoven fabric and a nonwoven fabric sheet (2) made of polypropylene, wherein the nonwoven fabric of the laminated sheet (1) is included in the composite sheet. The laminated sheet (1) has a resin film layer of 80-
A composite sheet for disposable diapers, comprising a resin composition comprising 20% by weight and 20 to 80% by weight of a polyethylene resin. 2. A disposable diaper using the composite sheet for disposable diapers according to claim 1, wherein the nonwoven fabric sheet (2) made of polypropylene is used as a top sheet, and the nonwoven fabric layer of the laminated sheet (1) is placed outside. Disposable diapers with sheets.