Absorbent sheet

Abstract

To provide an absorbent sheet resistant to creasing.SOLUTION: An absorbent sheet comprises a body part having a water permeable surface sheet, a back sheet on the opposite side of the surface sheet, and an absorber disposed between the surface sheet and the back sheet. The absorber includes an absorbent core containing thermoplastic resin fiber, with the thermoplastic resin fiber accounting for 30% or more by weight of the entire absorbent core. After a load of 3.0 kg is applied in a thickness direction for 10 minutes to the body part, which is folded along a fold line that traverses the absorbent core and partitions the body part into a first portion and a second portion, when the first portion is lifted vertically, the second portion separates naturally from the first portion, and the angle formed between the first and second portions is 145° or more.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to an absorbent sheet.

Background Art

[0002] Absorbent sheets that absorb liquids are widely used. For example, Patent Document 1 below describes a urine absorbent sheet for pets, which includes a water-permeable top sheet, a water-impermeable back sheet, and an absorber disposed between the top sheet and the back sheet, and the edges of the top sheet and the back sheet are joined.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Generally, absorbent sheets are folded and compressed, and then compactly stored in a package and sold. To enhance compactness, it is desirable to strongly compress the absorbent sheet. However, if a folded absorbent sheet is strongly compressed, the absorbent sheet may develop creases. If the absorbent sheet develops creases, it may not be possible to deform the absorbent sheet into the desired shape according to the intended use when taken out of the package, which may hinder the use of the absorbent sheet.

[0005] Therefore, an object of the present disclosure is to provide an absorbent sheet that is less likely to develop creases.

Means for Solving the Problems

[0006] The absorbent sheet according to one aspect includes a main body portion having a water-permeable surface sheet, a back sheet on the opposite side of the surface sheet, and an absorber disposed between the surface sheet and the back sheet. The absorber has an absorbent core containing thermoplastic resin fibers, and the proportion of the thermoplastic resin fibers in the entire absorbent core is 30% or more by weight. After applying a load of 3.0 kg in the thickness direction for 10 minutes to the main body portion folded along a broken line that divides the main body portion into a first portion and a second portion across the absorbent core, when the first portion is vertically lifted, the second portion naturally separates from the first portion, and the angle formed by the first portion and the second portion becomes 145° or more.

[0007] When an absorbent core containing pulp is bent, cellulose fibers, which are the main component of pulp, form hydrogen bonds and are joined together to form a fold. In contrast, in this aspect, the absorbent core contains thermoplastic resin fibers at a proportion of 30% or more by weight. Since thermoplastic resin fibers do not contain hydroxy groups and do not form hydrogen bonds unlike pulp, when the absorbent sheet is folded and compressed along a broken line, it is difficult for the absorbent sheet to have a fold. Therefore, when the folded absorbent sheet is taken out of the package, it is suppressed that the shape of the absorbent sheet is maintained in the folded state, and the absorbent sheet is naturally unfolded. As a result, the absorbent sheet can be made into a desired shape according to the intended use.

[0008] The broken line may be a double-fold line for folding the main body portion in half so that the back sheet is disposed on the inside. In this case, when the absorbent sheet housed in a double-fold is taken out of the package, it can be naturally unfolded.

[0009] The proportion of the thermoplastic resin fibers in the entire absorbent core may be 65% or more by weight. By setting the proportion of the thermoplastic resin fibers to 65% or more, it is possible to more effectively suppress the formation of folds in the absorbent sheet. As a result, the absorbent sheet can be easily unfolded when taken out of the package.

[0010] The average fiber length of the thermoplastic resin fibers may be 0.2 mm or more and 8.0 mm or less. By setting the average fiber length of the thermoplastic resin fibers within this range, it is possible to suppress the formation of creases in the absorbent sheet.

[0011] The absorber further includes a core wrap that covers the absorbent core, and the average fiber length of the thermoplastic resin fibers may be shorter than the average fiber length of the core wrap. Note that the average fiber length of the core wrap may be 100 mm or more. By making the average fiber length of the core wrap relatively long, the absorbent core can be stably held.

[0012] The core wrap includes a first core wrap sheet disposed between the top sheet and the absorbent core, and a second core wrap sheet disposed between the back sheet and the absorbent core, and at least one of the first core wrap sheet and the second core wrap sheet may contain synthetic fibers. By including synthetic fibers in at least one of the first core wrap sheet and the second core wrap sheet, the formation of creases in the core wrap can be suppressed.

[0013] Both the first core wrap sheet and the second core wrap sheet may contain synthetic fibers. By including synthetic fibers in both the first core wrap sheet and the second core wrap sheet, the formation of creases in the core wrap can be suppressed.

[0014] The first core wrap sheet may be composed of a tissue, and the second core wrap sheet may be composed of a non-woven fabric. When the main body is folded so that the back sheet is disposed inside, the folding angle of the second core wrap sheet becomes small, and creases are likely to be formed in the second core wrap sheet. By configuring the second core wrap sheet with a non-woven fabric, the formation of creases in the core wrap can be suppressed. Note that the non-woven fabric may be an SMS non-woven fabric.

[0015] The ratio of the thickness of the main body folded along the folding line after applying a load of 3.0 kg in the thickness direction for 10 minutes and then releasing the load and waiting for 3 minutes to the thickness of the main body folded along the folding line before applying the load may be 94% or more. In this absorbent sheet, since the thickness of the absorbent sheet recovers in a short time after the load is released, it is possible to suppress a decrease in the water absorption performance of the absorbent sheet.

[0016] The basis weight of the thermoplastic resin fibers in the region on the folding line of the absorbent core may be smaller than the basis weight of the thermoplastic resin fibers in the region other than the region on the folding line of the absorbent core. The absorbent core may contain thermoplastic resin fibers in the region on the folding line. By including thermoplastic resin fibers in the region on the folding line, a restoring force acts on the main body folded along the folding line, and the absorbent sheet can be naturally spread out.

[0017] The bending rigidity of the main body by the KES method may be 0.20 [gf·cm 2 / cm] or less. If the bending rigidity of the main body is high, the crease part may be hard and may give a sense of discomfort to the pet. By setting the bending rigidity of the main body to 0.20 [gf·cm 2 / cm] or less, it is possible to suppress the sense of discomfort given to the pet.

[0018] The thermoplastic resin fibers may be composed of an olefin resin or a PET resin. By configuring the thermoplastic resin fibers with an olefin resin or a PET resin, even if the absorbent sheet is folded and compressed along the folding line, it is difficult for creases to be formed in the absorbent sheet.

[0019] The back sheet has an inner surface facing the absorber and an outer surface on the opposite side of the surface, and an engaging portion for engaging with an excrement treatment sheet that absorbs the excrement of the pet is provided on the outer surface of the back sheet, and the engaging portion may be disposed at a position deviated from the folding line. In this case, it is possible to prevent creases from being formed in the engaging portion.

[0020] The area of the main body in plan view is 400 cm 2The following may be applicable. By significantly reducing the area of the main body part compared to a general excrement treatment sheet, the absorbent sheet can be used by overlapping it on a part of the excrement treatment sheet.

[0021] The absorbent sheet according to another aspect includes a main body part having a water-permeable surface sheet, a back sheet on the opposite side of the surface sheet, and an absorber disposed between the surface sheet and the back sheet. The absorber has an absorbent core containing thermoplastic resin fibers made of an olefin resin or a PET resin. A folding line is formed in the main body part that crosses the absorbent core. The back sheet has an inner surface facing the absorber and an outer surface on the opposite side of the surface. An engaging part that engages with an excrement treatment sheet for absorbing the excrement of a pet is provided on the outer surface of the back sheet, and the engaging part is disposed at a position offset from the folding line.

[0022] In this aspect, since the absorbent core contains thermoplastic resin fibers made of an olefin resin or a PET resin that do not form hydrogen bonds, it is difficult for creases to be formed in the absorbent sheet when the absorbent sheet is folded and compressed along the folding line. Also, when the engaging part is disposed on the folding line, there is a risk that creases will be formed in the engaging part when the absorbent sheet is folded along the folding line. In contrast, in this aspect, since the engaging part is disposed at a position offset from the folding line, when the absorbent sheet is folded along the folding line, the engaging part is prevented from bending, and as a result, the formation of creases in the absorbent sheet is suppressed.

[0023] The proportion of the thermoplastic resin fibers in the entire absorbent core may be 30% or more by weight ratio. By setting the proportion of the thermoplastic resin fibers to 30% or more, it is possible to more effectively suppress the formation of creases in the absorbent sheet.

[0024] The absorbent sheet is used by overlapping it on a part of an excrement treatment sheet for absorbing the excrement of an animal, and may have an area smaller than the area of the excrement treatment sheet. In this case, for example, in order to cover urine stains on the excrement treatment sheet, the absorbent sheet can be used by overlapping it on the excrement treatment sheet.

[0025] The thermoplastic resin fibers may be derived from the shredded nonwoven fabric. In this case, the absorbent core can be manufactured using the edge materials of the nonwoven fabric or the like as the material.

Advantages of the Invention

[0026] According to various aspects of the present invention, it is possible to suppress the formation of creases in the absorbent sheet.

Brief Description of the Drawings

[0027]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Modes for Carrying Out the Invention

[0028] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the description of the drawings, the same reference numerals are assigned to the same elements, and duplicate descriptions are omitted. The drawings may be drawn with some parts simplified or exaggerated for ease of understanding, and the dimensional ratios are not limited to those described in the drawings.

[0029] With reference to FIGS. 1 to 5, a pet sheet 1 according to an embodiment will be described. The pet sheet 1 is an example of an absorbent sheet that absorbs pet excrement. First, a usage example of the pet sheet 1 will be described with reference to FIG. 1. FIG. 1(A) shows an excrement treatment sheet (hereinafter referred to as "treatment sheet") 100 for pets. Typically, the treatment sheet 100 has a rectangular planar shape and includes a liquid-permeable surface sheet, a liquid-impermeable back sheet, and an absorber disposed between the surface sheet and the back sheet.

[0030] The treatment sheet 100 is disposed in a pet breeding space (for example, indoors) and is used to absorb and hold pet excrement to keep the breeding space clean. That is, the treatment sheet 100 provides a pet excretion space. The treatment sheet 100 may be placed directly on the floor or ground of the breeding space or on a tray.

[0031] In this specification, pets broadly include vertebrates and invertebrates, and typically include pet animals such as dogs, cats, rabbits, hamsters, etc. Pets include animals other than mammals such as birds, reptiles, and amphibians. As the pet excrement U, typically urine is mentioned, but it includes body fluids such as low-viscosity feces, saliva, and blood that can be absorbed by the absorber. In the following description, an example of absorbing urine as the excrement U will be described.

[0032] Pets tend to excrete while avoiding the excrement marks (urine marks) on the processing sheet 100. For this reason, as a result of the pet urinating in a strained posture in an attempt to avoid the urine marks, it may urinate outside the processing sheet 100, soiling the breeding space. To avoid such problems, the user of the processing sheet 100 (for example, the pet owner) may replace the processing sheet 100 with a new one even though there is an available area (an area capable of absorbing new urine). However, replacing the usable processing sheet 100 is not appropriate from the perspectives of both economy and environmental protection.

[0033] To solve the above problems, as shown in FIG. 1(B), the pet sheet 1 is used by being overlapped on the area where the excrement U of the processing sheet 100 has been absorbed (for example, the urine mark). By arranging the processing sheet 100 so as to overlap the urine mark, the urine mark can be visually hidden, so that it is possible to prevent the pet from urinating outside the processing sheet 100 while avoiding the urine mark. As a result, the processing sheet 100 can be repeatedly used for a long period of time, so improvements are achieved from the perspectives of economy and environmental protection.

[0034] On the other hand, the pet sheet 1 may be folded, compressed, and compactly stored in a package and sold. In order to enhance the compactness, it is desirable to strongly compress and package the pet sheet 1. However, if the folded pet sheet 1 is strongly compressed, there is a risk that the pet sheet 1 will develop creases. A crease is a streak-like wrinkle formed along the fold line L1 of the pet sheet 1.

[0035] If the pet sheet 1 develops creases, the absorbent sheet cannot be deformed into the desired shape according to the intended use when taken out of the package. Specifically, as shown in FIG. 2, if the pet sheet 1 has creases, the pet sheet 1 will not naturally spread out and will be placed on the processing sheet 100 in a state of being bent in a mountain shape. In this case, the portion of the pet sheet 1 placed on the processing sheet 100 will look locally raised, which may give the pet a sense of discomfort and cause the pet to dislike using the processing sheet 100.

[0036] To solve such problems, the pet sheet 1 is designed so that it is difficult to form folding habits and naturally unfolds when taken out of the package. When the pet sheet 1 naturally unfolds, the user can reduce the trouble of unfolding the pet sheet 1, and since the pet sheet 1 becomes flat on the processing sheet 100, the discomfort given to the pet can be reduced. Hereinafter, the structure of the pet sheet 1 will be described in detail.

[0037] FIG. 3 is a plan view of an exemplary pet sheet 1 as viewed from the surface sheet 2 side. FIG. 4 is a plan view of the pet sheet 1 as viewed from the back sheet 3 side. FIG. 5 is a schematic cross-sectional view of the pet sheet 1 taken along line IV-IV of FIG. 3. In the following description, the thickness direction of the pet sheet 1 is referred to as the Z direction, and the two directions perpendicular to each other when viewed from the Z direction are referred to as the X direction and the Y direction, respectively. The Y direction is a direction parallel to the folding line L1 of the pet sheet 1 described later.

[0038] As shown in FIGS. 3 and 4, the pet sheet 1 includes a main body portion 10 having a rectangular planar shape. Note that the planar shape of the main body portion 10 is not limited to a rectangular shape, and any shape such as a polygon, a circle, or an ellipse can be adopted. The size of the main body portion 10 is determined according to the size or type of the pet using the pet sheet 1. Typically, the area of the pet sheet 1 in plan view is smaller than the area of the processing sheet 100, for example, 400 cm 2 The following is.

[0039] The main body 10 has a surface sheet 2 with water permeability, a back sheet 3 on the opposite side of the surface sheet, and an absorber 4 disposed between the surface sheet 2 and the back sheet 3. The surface sheet 2 provides a surface 2a that faces the pet side (upward) during use. Typically, the surface sheet 2 is composed of a water-permeable non-woven fabric, which moves urine excreted from the pet toward the absorber 4 side. Examples of the non-woven fabric constituting the surface sheet 2 include air-through non-woven fabric, spunbond non-woven fabric, or point-bond non-woven fabric. The surface sheet 2 may be hydrophilized by a surfactant. In addition, in order to ensure visual unity, the surface sheet 2 of the pet sheet 1 may be composed of a non-woven fabric of the same color system as the surface sheet of the treatment sheet 100. Thereby, it is suppressed that the pet feels a sense of discomfort with the pet sheet 1.

[0040] The back sheet 3 is disposed on the opposite side of the surface sheet 2 in the Z direction and has water impermeability. The back sheet 3 has substantially the same dimensions as the surface sheet 2 and is arranged to completely overlap the surface sheet 2 when viewed from the Z direction. The back sheet 3 provides a back surface (outer surface) 3a that is placed on the treatment sheet 100 during use. Typically, the back sheet 3 is composed of a resin film with water impermeability. As the resin film constituting the back sheet 3, for example, a polyethylene film or a polypropylene film is used. Note that the back sheet 3 may be composed of a water-repellent or hydrophobic non-woven fabric, or may be a laminate in which a resin film and a non-woven fabric are bonded together.

[0041] The back sheet 3 prevents urine excreted on the pet sheet 1 from moving toward the treatment sheet 100 side. Note that the back sheet 3 may have water permeability. This is because since the treatment sheet 100 has a function of absorbing urine, there is no major problem even if urine excreted on the pet sheet 1 moves toward the treatment sheet 100 side.

[0042] The absorber 4 is disposed between the top sheet 2 and the back sheet 3 and absorbs the urine of pets. The absorber 4 has a substantially rectangular planar shape. As shown in FIG. 3, the absorber 4 has dimensions slightly smaller than those of the top sheet 2 and the back sheet 3 and is disposed at the center of the main body 10. As a result, an absorption portion 13 in which the absorber 4 is disposed between the top sheet 2 and the back sheet 3 and a flap portion 14 in which the absorber 4 is not disposed between the top sheet 2 and the back sheet 3 are formed in the main body 10. Typically, the flap portion 14 is a rectangular frame-shaped region where the top sheet 2 and the back sheet 3 are bonded together without passing through the absorber 4, and is formed so as to surround the absorption portion 13. That is, the flap portion 14 is formed along the outer edge of the pet sheet 1.

[0043] The rigidity of the flap portion 14 is lower than that of the absorption portion 13 because the absorber 4 is absent. That is, the flap portion 14 is thin and soft, so it is easy to pick up by hand. The double-folded pet sheet 1 can be naturally spread by picking up and lifting the flap portion 14.

[0044] As shown in FIG. 5, the absorber 4 includes an absorbent core 41 and a core wrap 42. The absorbent core 41 includes thermoplastic resin fibers made of a thermoplastic resin. The thermoplastic resin fibers are synthetic fibers composed of an olefin resin such as polyethylene (PE) or polypropylene (PP), or a polyethylene terephthalate resin (PET). Since these thermoplastic resin fibers do not have a hydroxy group, they have the property of not forming hydrogen bonds that cause creases.

[0045] The thermoplastic resin fibers can be produced by pulverizing a non-woven fabric made of synthetic resin with a pulverizer. The thermoplastic resin fibers can also be produced from the end materials of the non-woven fabric generated when manufacturing the PET sheet 1, the treated sheet 100, or other products. Generally, the non-woven fabric has a fiber length of about 30 mm to 51 mm. Since the thermoplastic resin fibers contained in the absorbent core 41 are produced by pulverizing the non-woven fabric, the fiber length of the thermoplastic resin fibers is shorter than that of general non-woven fabrics. The average fiber length of the thermoplastic resin fibers contained in the absorbent core 41 is, for example, 0.2 mm or more and 8.0 mm or less. The average fiber length of the thermoplastic resin fibers may be, for example, 0.2 mm or more and 0.35 mm or less. The thermoplastic resin fibers have a function of absorbing and diffusing the urine of the pet into the absorbent core 41 by capillary action.

[0046] The absorber 4 further contains a superabsorbent polymer (SAP). As the superabsorbent polymer, for example, particulate or fibrous polymers of polyacrylic acid-based, starch-based, or cellulose-based are used. When the thermoplastic resin fibers are entangled with the superabsorbent polymer, the superabsorbent polymer is retained within the absorbent core 41.

[0047] The ratio of the thermoplastic resin fibers in the entire absorbent core 41 is 30% or more, 40% or more, 50% or more, 60% or more, or 65% or more by weight. That is, the ratio of the superabsorbent polymer in the entire absorbent core 41 is 70% or less by weight. By increasing the ratio of the thermoplastic resin fibers, the diffusibility of urine is improved and the shape retention of the absorbent core 41 is enhanced. On the other hand, by increasing the weight ratio of the superabsorbent polymer, the water retention performance of the absorbent core 41 is improved. From the viewpoint of enhancing the shape retention of the absorbent core 41, the ratio of the thermoplastic resin fibers by weight may be higher than the ratio of the superabsorbent polymer.

[0048] The absorbent core 41 may further contain pulp. As the pulp, for example, cellulose pulp mainly composed of cellulose fibers is used. However, since cellulose fibers have hydroxy groups, the cellulose fibers form hydrogen bonds and bond to each other, making it easy for the absorbent core 41 to form creases. Therefore, from the viewpoint of suppressing the formation of creases, the proportion of pulp in the entire absorbent core 41 is preferably 50% or less by weight and lower than the proportion of thermoplastic resin fibers. The absorbent core 41 may be composed of thermoplastic resin fibers and a superabsorbent polymer without containing pulp.

[0049] The core wrap 42 is composed of, for example, a tissue or a nonwoven fabric sheet, and covers the upper surface 41a, side surface 41b, and lower surface 41c of the absorbent core 41. The core wrap 42 is adhered to the surface of the absorbent core 41 by, for example, a hot melt adhesive. The core wrap 42 may include a first core wrap sheet 42a and a second core wrap sheet 42b. The first core wrap sheet 42a is disposed between the surface sheet 2 and the absorbent core 41 and covers the upper surface 41a and side surface 41b of the absorbent core 41. The second core wrap sheet 42b is disposed between the back sheet 3 and the absorbent core 41 and covers the lower surface 41c of the absorbent core 41.

[0050] In one embodiment, at least one of the first core wrap sheet 42a and the second core wrap sheet 42b contains synthetic fibers having no hydroxy group. For example, the first core wrap sheet 42a is composed of a tissue, and the second core wrap sheet 42b is composed of a nonwoven fabric. The tissue enhances the diffusibility of urine, but is likely to have creases because it is composed of cellulose pulp. On the other hand, since the nonwoven fabric is composed of synthetic fibers that do not form hydrogen bonds, it is less likely to have creases. For example, as the nonwoven fabric constituting the second core wrap sheet 42b, an SMS nonwoven fabric in which spunbond, meltblown, and spunbond are laminated in this order is used.

[0051] When the main body 10 is folded so that the back sheet 3 is disposed inside, the bending angle of the second core wrap sheet 42b disposed inside in the bending direction is smaller than that of the first core wrap sheet 42a, so that a crease is likely to be formed in the second core wrap sheet 42b. Here, by forming the second core wrap sheet 42b of a nonwoven fabric, the formation of a crease in the second core wrap sheet 42b is suppressed.

[0052] When the main body 10 is folded so that the front sheet 2 is disposed inside, the first core wrap sheet 42a may be formed of a nonwoven fabric and the second core wrap sheet 42b may be formed of a tissue. The average fiber length of the nonwoven fabric constituting the first core wrap sheet 42a is 100 mm or more. That is, the average fiber length of the thermoplastic resin fibers contained in the absorbent core 41 is shorter than the average fiber length of the nonwoven fabric constituting the core wrap 42. By using a nonwoven fabric having a relatively long fiber length for the core wrap 42, leakage of the superabsorbent polymer from the absorbent core 41 is suppressed. Note that both the first core wrap sheet 42a and the second core wrap sheet 42b may be formed of a tissue. The average fiber length of the thermoplastic resin fibers contained in the absorbent core 41 may be shorter than the average fiber length of the tissue constituting the core wrap 42.

[0053] Also, both the first core wrap sheet 42a and the second core wrap sheet 42b may be formed of a nonwoven fabric. In this case, the formation of a crease in the core wrap 42 can be effectively suppressed.

[0054] As shown in FIGS. 4 and 5, an engaging portion 7 having an engaging surface 7a that can be coupled to the processing sheet 100 is provided on the back surface 3a of the back sheet 3. For example, the engaging portion 7 is a hook-and-loop fastener that engages with the surface of the processing sheet 100. Note that the engaging portion 7 may be an adhesive surface with a release paper. In the embodiment shown in FIG. 4, four rectangular engaging portions 7 are provided at the corner portions (four corners) of the back surface 3a. These four engaging portions 7 are arranged such that the outer edge portions of each engaging portion 7 are spaced apart from the outer edge of the back surface 3a. However, each engaging portion 7 may be arranged such that the outer edge portions of each engaging portion 7 coincide with the outer edge of the back surface 3a. The engaging portion 7 is provided in a state where the engaging surface 7a is exposed to the outside.

[0055] When the engaging portion 7 is a hook-and-loop fastener, a plurality of hooks protruding from the hook sheet are formed on the engaging surface 7a. When the pet sheet 1 is placed on the processing sheet 100, the pet sheet 1 is coupled to the processing sheet 100 by the plurality of hooks on the engaging surface 7a being entangled with the non-woven fabric constituting the surface sheet of the processing sheet 100. On the other hand, the shapes of the plurality of hooks are designed so that the engaging surfaces 7a of the engaging portions 7 are not coupled to each other.

[0056] The pet sheet 1 is stored in a folded state along a folding line L1 extending in the Y direction. As shown in FIG. 3, the folding line L1 extends in the Y direction so as to cross the absorbent core 41 along the center line of the main body portion 10 in the X direction. That is, the folding line L1 is a folding line for folding the pet sheet 1 in half. By this folding line L1, the main body portion 10 is partitioned into a first portion 11 located on one side (left side in FIG. 3) with respect to the folding line L1 and a second portion 12 located on the other side (right side in FIG. 3) with respect to the folding line L1.

[0057] When viewed from the thickness direction Z, the broken line L1 crosses the absorbent core 41 of the absorber 4. The absorbent core 41 also contains thermoplastic resin fibers in the region on the broken line L1. Thereby, a restoring force acts on the folded main body 10, making it easier for the pet sheet 1 to unfold. On the other hand, when the pet sheet 1 is bent along the broken line L1, the thermoplastic resin fibers are biased, and the basis weight of the thermoplastic resin fibers in the region of the absorbent core 41 on the broken line L1 may be smaller than the basis weight of the thermoplastic resin fibers in the regions other than the region of the absorbent core 41 on the broken line L1.

[0058] As shown in FIG. 3, the engaging portions 7 are arranged at positions shifted from the broken line L1 (positions that do not overlap the broken line L1). More specifically, the four engaging portions 7 are provided at positions that are line-symmetric with respect to the broken line L1. FIG. 6 shows the pet sheet 1 folded in half with the back surface 3a arranged inside along the broken line L1. As described above, since the four engaging portions 7 are provided at positions that are line-symmetric with respect to the broken line L1, when the pet sheet 1 is folded in half along the broken line L1, the two engaging portions 7 provided on the first portion 11 come into contact with the two engaging portions 7 provided on the second portion 12. Here, since the engaging portions 7 are designed such that the bonding surfaces 7a do not bond to each other, the first portion 11 and the second portion 12 are not bonded to each other in the folded state and are naturally separated.

[0059] FIG. 7 is a schematic cross-sectional view showing a package 50 that houses a plurality of pet sheets 1. The package 50 is, for example, a bag having a substantially rectangular parallelepiped shape and is made of a synthetic resin such as polyethylene, polypropylene, or polyethylene terephthalate. An opening line (not shown) is formed in the package 50, and by opening the package 50 along the opening line, an opening is formed for taking out the pet sheet 1 housed in the package 50.

[0060] As shown in Fig. 7, the pet sheet 1 is folded in half along the fold line L1 so that the back surface 3a is disposed inside, and is accommodated in the package 50 in a compressed state. When using the pet sheet 1, the user puts a finger into the package 50 through the opening of the package 50, and picks and pulls out the flap portion 14 of the first portion 11 or the second portion 12 of the pet sheet 1 to take out the pet sheet 1 from the package 50. Then, the pet sheet 1 is placed on the processing sheet 100 with the back surface 3a facing the processing sheet 100 side. At this time, if there is a fold mark along the fold line L1 on the pet sheet 1, as shown in Fig. 2, the pet sheet 1 will not naturally spread out and will be placed on the processing sheet 100 in a state of being bent in a mountain shape. In this case, the portion of the pet sheet 1 placed on the processing sheet 100 will look locally raised, which will give the pet a sense of discomfort.

[0061] Therefore, when the first portion 11 of the pet sheet 1 is vertically lifted, the pet sheet 1 is designed such that the second portion 12 naturally separates from the first portion 11 and the angle θ (see Fig. 2) formed between the first portion 11 and the second portion 12 is 145° or more. In the following description, the state in which the pet sheet 1 is folded along the fold line L1 is referred to as the "folded state", and the state in which the first portion 11 and the second portion 12 are separated is referred to as the "deployed state". Also, the function that when the first portion 11 of the pet sheet 1 compressed under predetermined conditions is vertically lifted, the angle θ formed between the first portion 11 and the second portion 12 is 145° or more is referred to as the "deployment function".

[0062] Whether the pet sheet 1 has the above-described deployment function or not is confirmed by the following deployment function test. In the deployment function test, first, three folded pet sheets 1 in the folded state are stacked and placed on a horizontal table in an environment of constant temperature and humidity (room temperature 20°C, humidity 60%). Next, a weight of 3.0 kg (5.3×10 3 [N / m 2) is applied for 10 minutes. Then, the load on the pet sheet 1 is released, and as shown in FIG. 8(A), the first portion 11 of the pet sheet 1 is vertically lifted. When the first portion 11 is vertically lifted, as shown in FIG. 8(B), the second portion 12 naturally separates from the first portion 11, and the pet sheet 1 is in a deployed state.

[0063] Next, the angle θ formed between the first portion 11 and the second portion 12 is measured. The angle θ is measured for each of the three pet sheets 1, and the average value of the angle θ is obtained. If the average value of the angle θ is 145° or more, it is determined that the pet sheet 1 has a deployment function.

[0064] The angle θ depends on the ratio of the thermoplastic resin fibers in the entire absorbent core 41, and tends to increase as the ratio of the thermoplastic resin fibers increases. This is because when the ratio of the thermoplastic resin fibers is high, the formation of creases is suppressed, and the pet sheet 1 is likely to spread. As described above, in the pet sheet 1, the ratio of the thermoplastic resin fibers in the entire absorbent core 41 is set to 30% or more by weight ratio, and it has a deployment function.

[0065] Also, the pet sheet 1 has a high compression recovery rate. The compression recovery rate means the ratio between the thickness of the pet sheet 1 in the double-folded state before compression and the thickness of the pet sheet 1 in the double-folded state after compression. The compression recovery rate depends on the ratio of the thermoplastic resin fibers in the entire absorbent core 41, and tends to increase as the ratio of the thermoplastic resin fibers increases. Specifically, the ratio (compression recovery rate) of the thickness of the main body portion 10 of the pet sheet 1 in the double-folded state 3 minutes after releasing the load, which is obtained by applying a load of 3.0 kg in the thickness direction to the main body portion 10 of the pet sheet 1 in the double-folded state for 10 minutes and then releasing the load, to the thickness of the main body portion 10 of the pet sheet 1 in the double-folded state before pressurization may be 94% or more. By having a high compression recovery rate of 94% or more, the thickness of the compressed pet sheet 1 can be recovered in a short time, so that a decrease in the water absorption performance of the pet sheet 1 can be suppressed. By setting the ratio of the thermoplastic resin fibers in the entire absorbent core 41 to 30% or more by weight ratio, the compression recovery rate of the pet sheet 1 can be made 94% or more.

[0066] Also, the bending rigidity of the main body 10 of the pet sheet 1 according to the KES method may be 0.20 [gf·cm 2 / cm] or less. The bending rigidity according to the KES method is measured, for example, using a large bending tester KES-FB-L manufactured by Kato Tech Co., Ltd. When measuring the bending rigidity, a 10 cm × 10 cm test piece is cut out from the absorption part 13 of the pet sheet 1, one end in the longitudinal direction of the test piece is attached to the first chuck of the bending tester, and the other end in the longitudinal direction of the test piece is attached to the second chuck of the bending tester. Then, the first chuck is rotated around the second chuck, and the bending rigidity of the bent test piece is measured with a torque detector. The same test is performed on five test pieces, and the average value of the measured values is taken as the bending rigidity. The lower the measured bending rigidity, the softer the sheet.

[0067] The bending rigidity depends on the ratio of the thermoplastic resin fibers in the entire absorbent core 41, and tends to decrease as the ratio of the thermoplastic resin fibers increases. By setting the ratio of the thermoplastic resin fibers in the entire absorbent core 41 to 30% or more by weight, the bending rigidity of the main body 10 can be made 0.20 [gf·cm 2 / cm] or less. By reducing the bending rigidity of the main body 10, it is possible to suppress the main body 10 from deforming following the superabsorbent polymer that has absorbed urine and swollen, and the formation of unevenness on the surface of the pet sheet 1. Also, if the bending rigidity of the main body 10 is high, the folded part may be hard and give the pet a sense of discomfort. By making the bending rigidity of the main body 10 0.20 [gf·cm 2 / cm] or less, it is possible to suppress the sense of discomfort given to the pet.

[0068] As described above, in the pet sheet 1, the absorbent core 41 contains 30% or more of thermoplastic resin fibers by weight ratio. Since the thermoplastic resin fibers do not contain a hydroxy group and do not form a hydrogen bond unlike pulp, when the pet sheet 1 is folded and compressed along the folding line L1, the formation of a crease in the pet sheet 1 is suppressed. Therefore, as shown in FIG. 7, when the pet sheet 1 accommodated in the double-folded state is taken out from the package 50, the pet sheet 1 is naturally unfolded and can be directly pasted onto the processing sheet 100. At this time, since the pet sheet 1 has a deployment function, it is difficult for the pet sheet 1 to bend into a mountain shape on the processing sheet 100, and it is possible to prevent the portion where the pet sheet 1 is disposed from looking locally swollen. Therefore, the visual discomfort of the pet can be reduced.

[0069] In addition, since the pet sheet 1 has a deployment function, when the user takes out the double-folded pet sheet 1 from the package 50, if the user grasps and takes out the first portion 11 or the second portion 12 of the pet sheet 1 with one hand, the pet sheet 1 will be naturally unfolded. Therefore, the labor of the user to unfold the pet sheet 1 with both hands is reduced. Further, since it is difficult to form a crease in the pet sheet 1, the pet sheet 1 can be accommodated in a strongly compressed state in the package 50. Therefore, it is possible to store the pet sheet 1 compactly.

[0070] Hereinafter, various experimental examples of the pet sheet 1 will be described, but the present invention is not limited to the following experimental examples.

[0071] FIG. 9 shows the experimental results of the relationship between the proportion of thermoplastic resin fibers in the entire absorbent core 41 and the angle θ formed between the first part 11 and the second part 12 of the PET sheet 1. That is, the proportion of superabsorbent polymer (SAP) in the entire absorbent core 41 is 35% by weight. Samples A to F of PET sheets with different proportions of thermoplastic resin fibers were prepared. Using these samples A to F, the above-described unfolding function test was performed, and the angle θ was measured. Further, after the unfolding function test, samples A to F were placed on the treatment sheet 100, and the height H (see FIG. 2) from the surface of the treatment sheet 100 to the fold line L1 of samples A to F was measured, and the visual discomfort was evaluated by a sensory test. In the item of "discomfort" in FIG. 9, "A" indicates little discomfort, "B" indicates a little discomfort, and "C" indicates a large discomfort.

[0072] Specifically, in sample A, the proportion of pulp mainly composed of cellulose fibers (hereinafter simply referred to as "pulp") was 65% by weight, and the proportion of thermoplastic resin fibers was 0% by weight. In sample B, the proportion of pulp was 52% by weight, and the proportion of thermoplastic resin fibers was 13% by weight. In sample C, the proportion of pulp was 39% by weight, and the proportion of thermoplastic resin fibers was 26% by weight. In sample D, the proportion of pulp was 32.5% by weight, and the proportion of thermoplastic resin fibers was 32.5% by weight. In sample E, the proportion of pulp was 26% by weight, and the proportion of thermoplastic resin fibers was 39% by weight. In sample F, the proportion of pulp was 0% by weight, and the proportion of thermoplastic resin fibers was 65% by weight.

[0073] As shown in FIG. 9, it was confirmed that the angle θ increases as the proportion of thermoplastic resin fibers in the entire absorbent core 41 increases. In particular, it was confirmed that when the proportion of thermoplastic resin fibers is 32.5% or more by weight, the angle θ becomes 151° or more, and the visual discomfort when the PET sheet is placed on the treatment sheet can be reduced.

[0074] Figure 10 shows the experimental results of the relationship between the proportion of thermoplastic resin fibers in the entire absorbent core 41 and the bending rigidity of the main body 10 of the PET sheet 1. In this experiment, the above-described samples A to F were prepared, a 10 cm × 10 cm test piece was cut out from the absorption part of the samples A to F, and the bending rigidity of the test piece was measured using a large bending tester KES-FB-L manufactured by Kato Tech Co., Ltd.

[0075] As shown in Figure 10, it was confirmed that the bending rigidity decreases as the proportion of thermoplastic resin fibers in the entire absorbent core 41 increases. In particular, if the proportion of thermoplastic resin fibers is 32.5% or more by weight ratio, the bending rigidity can be made 0.20 [gf·cm 2 / cm] or less.

[0076] Figure 11 shows the experimental results of the relationship between the proportion of thermoplastic resin fibers in the entire absorbent core 41 and the compression recovery rate of the main body 10 of the PET sheet 1. In this experiment, the above-described samples A to F were prepared, a load of 3.0 kg was applied to the samples A to F in the folded state from the thickness direction for 10 minutes, the load was released, and the thickness of the samples A to F after 3 minutes was measured. The ratio of the thickness of the samples A to F in the folded state before and after applying the load was defined as the compression recovery rate. As shown in Figure 11, it was confirmed that the compression recovery rate increases as the proportion of thermoplastic resin fibers in the entire absorbent core 41 increases. In particular, if the proportion of thermoplastic resin fibers is 32.5% or more by weight ratio, the compression recovery rate can be made 94% or more.

[0077] As described above, the PET sheet 1 according to various embodiments has been described. However, the present invention can be configured in various modified forms without being limited to the above-described embodiments and without changing the gist of the invention. That is, it should be noted that the above-described embodiments are for illustrative purposes and do not limit the scope of the present invention.

[0078] In the above embodiment, the proportion of the thermoplastic resin fibers in the entire absorbent core 41 is 30% or more by weight, but the proportion of the thermoplastic resin fibers may be 30% or less by weight. At least if the absorbent core 41 contains thermoplastic resin fibers composed of an olefin resin or a PET resin, it is possible to suppress the formation of creases in the pet sheet 1.

[0079] In the above embodiment, the folding line L1 is a double-fold line for folding the pet sheet 1 in half, but as long as it crosses the absorbent core 41 and divides the main body portion 10 into a first portion 11 and a second portion 12, the folding line L1 does not have to be a double-fold line. For example, the folding line L1 may extend in a direction inclined with respect to the outer edge of the main body portion 10.

[0080] In the embodiment shown in FIG. 7, the pet sheet 1 is housed in the package 50 in a state of being folded in half along the folding line L1 with the back surface 3a disposed inside, but the pet sheet 1 may be housed in the package 50 in a state of being folded in half along the folding line L1 with the front surface 2a disposed inside. In this case, the engaging portion 7 will contact the adjacent pet sheet 1 within the package 50, but since the bonding surface 7a of the engaging portion 7 is designed not to bond to the back sheet 3, the adjacent pet sheets 1 are prevented from being bonded to each other.

[0081] The pet sheet 1 may not be provided with the engaging portion 7. For example, an adhesive may be applied to a part or the whole of the back surface 3a of the back sheet 3, and a release paper may be provided on the back surface 3a. In this case, the back sheet 3 can be pasted on the treatment sheet 100 after peeling off the release paper.

[0082] The present disclosure includes the following content.

[0083] [1] A main body portion having a water-permeable front sheet, a back sheet on the opposite side of the front sheet, and an absorber disposed between the front sheet and the back sheet. The absorber has an absorbent core containing thermoplastic resin fibers, and the proportion of the thermoplastic resin fibers in the entire absorbent core is 30% or more by weight. After applying a load of 3.0 kg in the thickness direction for 10 minutes to the main body portion folded along a folding line that divides the main body portion into a first portion and a second portion across the absorbent core, when the first portion is vertically lifted, the second portion naturally separates from the first portion and the angle formed by the first portion and the second portion is 145° or more. An absorbent sheet.

[0084] [2] The absorbent sheet according to [1], wherein the folding line is a double-fold line for folding the main body portion in half so that the back sheet is disposed inside.

[0085] [3] The absorbent sheet according to [1] or [2], wherein the proportion of the thermoplastic resin fibers in the entire absorbent core is 65% or more by weight.

[0086] [4] The absorbent sheet according to any one of [1] to [3], wherein the average fiber length of the thermoplastic resin fibers is 0.2 mm or more and 8.0 mm or less.

[0087] [5] The absorber further includes a core wrap that covers the absorbent core. The absorbent sheet according to any one of [1] to [4], wherein the average fiber length of the thermoplastic resin fibers is shorter than the average fiber length of the core wrap.

[0088] [6] The absorbent sheet according to [5], wherein the average fiber length of the core wrap is 100 mm or more.

[0089] [7] The core wrap includes a first core wrap sheet disposed between the surface sheet and the absorbent core, and a second core wrap sheet disposed between the back sheet and the absorbent core. The absorbent sheet according to [5] or [6], wherein at least one of the first core wrap sheet and the second core wrap sheet contains synthetic fibers.

[0090] [8] The absorbent sheet according to [7], wherein both the first core wrap sheet and the second core wrap sheet contain the synthetic fiber.

[0091] [9] The absorbent sheet according to [7], wherein the first core wrap sheet is composed of a tissue and the second core wrap sheet is composed of a nonwoven fabric.

[0092]

[10] The absorbent sheet according to [9], wherein the nonwoven fabric is an SMS nonwoven fabric.

[0093]

[11] The ratio of the thickness of the main body portion folded along the folding line after releasing a load of 3.0 kg in the thickness direction for 10 minutes and then waiting for 3 minutes to the thickness of the main body portion folded along the folding line before pressurization is 94% or more. The absorbent sheet according to any one of [1] to

[10] .

[0094]

[12] The basis weight of the thermoplastic resin fibers in the region on the folding line of the absorbent core is smaller than the basis weight of the thermoplastic resin fibers in the region other than the region on the folding line of the absorbent core. The absorbent sheet according to any one of [1] to

[11] .

[0095]

[13] The absorbent core contains the thermoplastic resin fibers in the region on the folding line. The absorbent sheet according to

[12] .

[0096]

[14] The bending rigidity of the main body portion by the KES method is 0.20 [gf·cm 2 / cm] or less. The absorbent sheet according to any one of [1] to

[13] .

[0097]

[15] The thermoplastic resin fibers are composed of an olefin resin or a PET resin. The absorbent sheet according to any one of [1] to

[14] .

[0098]

[16] The back sheet has an inner surface facing the absorber and an outer surface on the opposite side of the surface. An engaging portion that engages with an excrement treatment sheet for absorbing pet excrement is provided on the outer surface of the back sheet. The engaging portion is disposed at a position deviated from the folding line, and the absorbent sheet according to any one of [1] to

[15] .

[0099]

[17] The area of the main body portion in a plan view is 400 cm 2 The absorbent sheet according to any one of [1] to

[16] below.

[0100]

[18] A main body portion including a water-permeable surface sheet, a back sheet on the opposite side of the surface sheet, and an absorber disposed between the surface sheet and the back sheet. The absorber has an absorbent core containing thermoplastic resin fibers made of an olefin resin or a PET resin. A folding line that crosses the absorbent core is formed in the main body portion. The back sheet has an inner surface facing the absorber and an outer surface on the opposite side of the surface. An engaging portion that engages with an excrement treatment sheet for absorbing pet excrement is provided on the outer surface of the back sheet. The engaging portion is disposed at a position deviated from the folding line. Absorbent sheet.

[0101]

[19] The ratio of the thermoplastic resin fibers in the entire absorbent core is 30% or more by weight, and the absorbent sheet according to

[18] .

[0102]

[20] It is used by being overlapped on a part of an excrement treatment sheet for absorbing pet excrement and has an area smaller than the area of the excrement treatment sheet, and the absorbent sheet according to

[18] or

[19] .

[0103]

[21] The thermoplastic resin fibers are derived from a shredded nonwoven fabric, and the absorbent sheet according to any one of

[18] to

[20] .

Description of symbols

[0104] 1… Pet sheet (absorbent sheet), 2… Surface sheet, 2a… Surface, 3… Back sheet, 3a… Back (outer surface), 4… Absorbent body, 7… Engaging part, 10… Main body part, 11… First part, 12… Second part, 41… Absorbent core, 42… Core wrap, 42a… First core wrap sheet, 42b… Second core wrap sheet, 100… Excrement treatment sheet, L1… Fold line, U… Excrement, θ… Angle.

Claims

1. A main body portion having a water-permeable surface sheet, a back surface sheet on the opposite side of the surface sheet, and an absorber disposed between the surface sheet and the back surface sheet, The absorber has an absorbent core containing thermoplastic resin fibers, and the proportion of the thermoplastic resin fibers in the entire absorbent core is 30% or more by weight ratio, After applying a load of 3.0 kg in the thickness direction for 10 minutes to the main body portion folded along a folding line that divides the main body portion into a first portion and a second portion across the absorbent core, when the first portion is vertically lifted, the second portion naturally separates from the first portion, and the angle formed by the first portion and the second portion is 145° or more, an absorbent sheet.

2. The absorbent sheet according to claim 1, wherein the folding line is a double-fold line for folding the main body portion in half so that the back surface sheet is disposed inside.

3. The absorbent sheet according to claim 1, wherein the proportion of the thermoplastic resin fibers in the entire absorbent core is 65% or more by weight ratio.

4. The absorbent sheet according to claim 1, wherein the average fiber length of the thermoplastic resin fibers is 0.2 mm or more and 8.0 mm or less.

5. The absorber further includes a core wrap that covers the absorbent core, The absorbent sheet according to claim 1, wherein the average fiber length of the thermoplastic resin fibers is shorter than the average fiber length of the core wrap.

6. The absorbent sheet according to claim 5, wherein the average fiber length of the core wrap is 100 mm or more.

7. The core wrap includes a first core wrap sheet disposed between the surface sheet and the absorbent core, and a second core wrap sheet disposed between the back surface sheet and the absorbent core, The absorbent sheet according to claim 5, wherein at least one of the first core wrap sheet and the second core wrap sheet contains synthetic fibers.

8. The absorbent sheet according to claim 7, wherein both the first core wrap sheet and the second core wrap sheet contain the synthetic fibers.

9. The absorbent sheet according to claim 7, wherein the first core wrap sheet is composed of a tissue, and the second core wrap sheet is composed of a non-woven fabric.

10. The absorbent sheet according to claim 9, wherein the non-woven fabric is an SMS non-woven fabric.

11. The ratio of the thickness of the main body portion folded along the folding line after a load of 3.0 kg has been applied to the main body portion folded along the folding line in the thickness direction for 10 minutes and then the load has been removed and 3 minutes have passed to the thickness of the main body portion before pressurization is 94% or more. The absorbent sheet according to claim 1.

12. The basis weight of the thermoplastic resin fibers in the region on the folding line of the absorbent core is smaller than the basis weight of the thermoplastic resin fibers in the region other than the region on the folding line of the absorbent core. The absorbent sheet according to claim 1.

13. The absorbent core includes the thermoplastic resin fibers in the region on the folding line. The absorbent sheet according to claim 12.

14. The bending rigidity of the main body part by the KES method is 0.20 [gf·cm 2 / cm] or less, the absorbent sheet according to claim 1.

15. The thermoplastic resin fibers are composed of an olefin resin or a PET resin. The absorbent sheet according to claim 1.

16. The back sheet has an inner surface facing the absorber and an outer surface on the side opposite to the surface, and an engaging portion for engaging with an excrement treatment sheet that absorbs pet excrement is provided on the outer surface of the back sheet, and the engaging portion is disposed at a position offset from the folding line. The absorbent sheet according to claim 1.

17. The area of the main body portion in a plan view is 400 cm ２ The absorbent sheet according to claim 1, which is as follows.

18. A main body portion including a water-permeable surface sheet, a back sheet on the side opposite to the surface sheet, and an absorber disposed between the surface sheet and the back sheet, the absorber having an absorbent core containing thermoplastic resin fibers made of an olefin resin or a PET resin, a folding line that crosses the absorbent core being formed in the main body portion, the back sheet having an inner surface facing the absorber and an outer surface on the side opposite to the surface, and an engaging portion for engaging with an excrement treatment sheet that absorbs pet excrement being provided on the outer surface of the back sheet, the engaging portion being disposed at a position offset from the folding line, Absorbent sheet.

19. The proportion of the thermoplastic resin fibers in the entire absorbent core is 30% or more by weight. The absorbent sheet according to claim 18.

20. It is used by being overlapped with a part of an excrement treatment sheet that absorbs pet excrement and has an area smaller than the area of the excrement treatment sheet. The absorbent sheet according to claim 18.

21. The thermoplastic resin fibers are derived from a shredded nonwoven fabric. The absorbent sheet according to claim 18.

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