Excrement hiding absorbent sheet for pets

An absorbent sheet for pets that is highly effective in concealing pet excrement. The absorbent sheet includes: a liquid-permeable front-surface sheet; a liquid-impermeable back-surface sheet; an absorbent body that is provided between the front-surface sheet and the back-surface sheet, and that absorbs liquid that has permeated through the front-surface sheet; an intermediate sheet that is arranged between the front-surface sheet and the absorbent body; and a color arrangement region that forms a color arrangement pattern together with at least one of the front-surface sheet, the back-surface sheet, and the absorbent body. The front-surface sheet is formed so as to have a lower total light transmittance than the intermediate sheet.

RELATED APPLICATIONS

This application is a 35 U.S.C. § 371 national phase filing of International Patent Application No. PCT/JP2013/080952, filed Nov. 15, 2013, through which and to which priority is claimed under 35 U.S.C. § 119 to Japanese Patent Application No. 2012-272364, filed Dec. 13, 2012, the entire disclosure of which is hereby expressly incorporated by reference.

TECHNICAL FIELD

The present invention relates to an absorbent sheet for pets, more particularly to an absorbent sheet for pets which has excellent concealability for excrement.

BACKGROUND ART

Conventionally, absorbent sheets for pets have been provided to be used particularly for disposing excrement of pets which are kept indoors. For example, Japanese Unexamined Patent Application Publication JP 2012-130285A discloses an absorbent sheet for pets.

In the absorbent sheet according to this prior art, an intermediate sheet is disposed between a liquid-permeable top sheet and an absorber. Further, a colored sheet containing a black component is disposed between the intermediate sheet and the absorber.

The top sheet is light transmissive. The intermediate sheet has an L* value larger than the black component of the colored sheet, can retain liquid, and has a lower light transmittance than the top sheet.

By provision of such a structure, when a pet excretes urine on the prior art absorbent sheet, part of urine is retained by the intermediate sheet. Further, with the structure in which the colored sheet is disposed on the back surface side of the intermediate sheet and the light transmissive top sheet is disposed on the top surface side of the intermediate sheet, a user can easily recognize an outline of urine retained in the intermediate sheet, from the top sheet side.

Depending on a desired absorbent sheet for pets, however, it may be desired to make the outline of excreted urine less visible from the top sheet.

PRIOR ART DOCUMENT

Patent Document

Patent Document 1:

JP 2012-130285 A

SUMMARY OF THE INVENTION

Problem to be Solved by the Invention

Accordingly, it is an object of the present invention to provide an absorbent sheet for pets which has excellent concealability for excrement.

Means for Solving the Problem

In order to solve the above-described problem, according to a preferred aspect of the present invention, an absorbent sheet for pets is provided which includes an excretion surface on which a pet excretes, a placing surface that is opposite to the excretion surface, a liquid-permeable top sheet that is disposed on the excretion surface side, a liquid-impermeable back sheet that is disposed on the placing surface side, an absorber that is disposed between the top sheet and the back sheet and absorbs liquid which has penetrated the top sheet, a core layer that is provided in the absorber and has a core layer top surface formed on a side of the core layer facing the excretion surface, a core layer back surface formed on a side of the core layer facing the placing surface, and a core layer side surface between the core layer top surface and the core layer back surface, a covering sheet that covers at least part of the core layer top surface, and an intermediate sheet that is disposed between the top sheet and the absorber. Further, the absorbent sheet for pets has a coloration region that is visible from the excretion surface side and forms a coloration pattern together with other regions of the absorbent sheet, and the top sheet is formed to have a lower total light transmittance than the intermediate sheet.

According to a further aspect of the absorbent sheet of the present invention, difference in total light transmittance between the top sheet and the intermediate sheet is 1 to 50%.

According to a further aspect of the absorbent sheet of the present invention, the total light transmittance of the top sheet is 40 to 80%.

According to a further aspect of the absorbent sheet of the present invention, the total light transmittance of the intermediate sheet is 60 to 90%.

According to a further aspect of the absorbent sheet of the present invention, the top sheet has a plurality of ridges and grooves that are each formed between adjacent ones of the ridges.

According to a further aspect of the absorbent sheet of the present invention, the intermediate sheet is formed of a composite nonwoven fabric having a meltblown nonwoven fabric layer between two spun-bond nonwoven fabric layers and having a basis weight of 8 to 25 g/m2.

According to a further aspect of the absorbent sheet of the present invention, the coloration region has an L* value of 50 or less in an L*a*b* color system, wherein “L” represents lightness and “a” and “b” represent green-red and blue-yellow color components respectively.

According to a further aspect of the absorbent sheet of the present invention, the coloration region has an L* value larger than 0 but smaller than 100 and a b* value larger than −0.4a in an L*a*b* color system.

According to a further aspect of the absorbent sheet of the present invention, the coloration region is formed in the covering sheet.

According to a further aspect of the absorbent sheet of the present invention, the covering sheet includes a first covering sheet that covers at least part of the core layer top surface and a second covering sheet that covers at least part of the core layer back surface, and the coloration region is formed in the first covering sheet.

According to a further aspect of the absorbent sheet of the present invention, the covering sheet is formed by a third covering sheet that covers the core layer back surface and the coloration region is formed in the third covering sheet.

According to a further aspect of the absorbent sheet of the present invention, a plurality of the intermediate sheets are provided.

According to a further aspect of the absorbent sheet of the present invention, the coloration region is formed in the intermediate sheet.

According to a further aspect of the absorbent sheet of the present invention, the coloration region is formed in the top sheet.

According to a further aspect of the absorbent sheet of the present invention, the coloration region is formed in the core layer.

Effect of the Invention

According to the present invention, an absorbent sheet for pets can be provided which has high concealability for pet excrement.

BEST MODES FOR CARRYING OUT THE INVENTION

First Embodiment

A first embodiment of an absorbent sheet for pets according to the present invention is now explained with reference toFIGS. 1 to 3. The “pet” in this embodiment widely includes vertebrates (mammals, reptiles, birds and amphibians) and invertebrates, and typically represents pets such as cats, dogs, rabbits and hamsters.

The pet absorbent sheet100is a flat sheet having a prescribed thickness. The pet absorbent sheet100has a pet use mode in which it is spread out flat with a back sheet160placed on an intended place and receives excrement of pets. The pet absorbent sheet according to this embodiment preferably has a rectangular or square shape, but it may have a circular, elliptical or polygonal shape. The “excrement of pets” as used herein widely includes not only urine, but body fluids such as saliva and menstrual blood. In the pet use mode, a top sheet100has a planar structure serving both as a flat excrement receiving surface (hereinafter also referred to as a main absorbing region) for receiving excrement of pets in non-contact with pets and as a pet walking surface on which the pet can walk. The manner of placing the pet absorbent sheet on the “intended place” includes a manner of directly placing the pet absorbent sheet on floor or the like, and a manner of setting the pet absorbent sheet on a holder and placing it on floor or the like.

FIG. 1is a perspective view showing the overall structure of the pet absorbent sheet100according to the first embodiment of the present invention.FIG. 2schematically shows the sectional structure of the pet absorbent sheet100in a sectional view taken along line A-A inFIG. 1.

The pet absorbent sheet100has an excretion surface101on which a pet excretes in the pet use mode and a placing surface102which comes in contact with the intended place. The placing surface102is opposite to the excretion surface101.

The excretion surface101is an example embodiment that corresponds to the “excretion surface on which a pet excretes” according to the present invention.

The placing surface102is an example embodiment that corresponds to the “placing surface opposite to the excretion surface” according to the present invention.

The pet absorbent sheet100has a liquid-permeable top sheet110which is disposed on the excretion surface101side. The top sheet110is an example embodiment that corresponds to the “liquid-permeable top sheet which is disposed on the excretion surface side” according to the present invention.

Further, the pet absorbent sheet100has a liquid-impermeable back sheet160which is disposed on the placing surface102side. The back sheet160is an example embodiment that corresponds to the “liquid-impermeable back sheet which is disposed on (a side of) the placing surface” according to the present invention.

The pet absorbent sheet100further has an absorber140that is disposed between the top sheet110and the back sheet160and absorbs liquid which has penetrated the top sheet110. The absorber140is an example embodiment that corresponds to the “absorber that is disposed between the top sheet and the back sheet and absorbs liquid which has penetrated the top sheet” according to the present invention.

The pet absorbent sheet100further has an intermediate sheet120that is disposed between the top sheet110and the absorber140. The intermediate sheet120is an example embodiment that corresponds to the “intermediate sheet that is disposed between the top sheet and the absorber” according to the present invention.

The pet absorbent sheet100further has a coloration region130that is visible from the excretion surface101side and forms a coloration pattern together with other regions of the pet absorbent sheet100.

The coloration region130is an example embodiment that corresponds to the “coloration region that is visible from the excretion surface side and forms a coloration pattern together with other regions of the absorbent sheet” according to the present invention.

Further, the “coloration pattern” in the present invention does not only refer to color. For example, it is a concept including lightness and brightness. Specifically, the condition that “the coloration pattern is different” in the present invention is only necessary to make a user recognize a difference in coloration.

At this time, for example in a sectional view as shown inFIG. 2, the coloration pattern only needs to be formed by a part having the coloration region130and other parts.

Further, the specific structure of the coloration region130will be described below.

The top sheet110and the back sheet160are formed to be slightly larger than the absorber140. Peripheral edges of the top sheet110and the back sheet160are bonded together at an edge end bonding part154, with the intermediate sheet120, the coloration region130and the absorber140disposed between the top sheet110and the back sheet160.

The top sheet110may be formed of thermoplastic nonwoven fabric, including a spun-bond nonwoven fabric of thermoplastic long fibers, a through-air nonwoven fabric of thermoplastic short fibers, a point-bond nonwoven fabric and a perforated film.

Particularly as the top sheet110according to the present invention, a through-air nonwoven fabric is used.

The top sheet110has ridges111, grooves112which are each formed between adjacent ones of the ridges111, and openings113which are formed at intervals and extend along the grooves112.

The ridges111and the grooves112which are formed on the top sheet110are example embodiments that correspond to the feature that “the top sheet has a plurality of ridges and grooves each formed between adjacent ones of the ridges” according to the present invention.

The ridges111and the grooves112of the top sheet form a surface layer of the excretion surface101, or a part of the pet absorbent sheet which is closest to the user when the user visually checks the absorbent sheet. Thus, when the user visually checks the pet absorbent sheet100, the ridges111and the grooves112of the top sheet110are first strongly recognized by the user. As a result, especially an outline of liquid excrement can be prevented from being easily recognized.

The top sheet110is configured to have a lower total light transmittance than the intermediate sheet120. This is an example embodiment that corresponds to the feature that “the top sheet is formed to have a lower total light transmittance than the intermediate sheet” according to the present invention.

Reduction of the total light transmittance of the top sheet110is realized by increasing the thickness of the top sheet110, increasing the amount of titanium oxide to be added to the synthetic fibers for forming the top sheet110, or increasing the fiber density of the top sheet110.

Difference in total light transmittance between the top sheet110and the intermediate sheet120is preferably 1 to 50%. This is an example embodiment that corresponds to the “difference in total light transmittance between the top sheet and the intermediate sheet is 1 to 50%” according to the present invention.

Further, the total light transmittance of the top sheet110is preferably 40 to 80%. This is an example embodiment that corresponds to the “total light transmittance of the top sheet is preferably 40 to 80%” according to the present invention.

The intermediate sheet120may be formed of thermoplastic nonwoven fabric, including a through-air nonwoven fabric, a point-bond nonwoven fabric or spun-bond nonwoven fabric.

Particularly as the intermediate sheet120according to the present invention, preferably, a composite nonwoven fabric having a meltblown nonwoven fabric layer123between a first spun-bond nonwoven fabric layer121and a second spun-bond nonwoven fabric layer122is used. The composite nonwoven fabric may be referred to as SMS (spunbond/meltblown/spunbond) nonwoven fabric. It is preferable that the SMS nonwoven fabric to be used for the intermediate sheet120has a basis weight of 8 to 25 g/m2.

The intermediate sheet120is an example embodiment that corresponds to the “intermediate sheet that comprises a composite nonwoven fabric having a meltblown nonwoven fabric layer between two spun-bond nonwoven fabric layers and having a basis weight of 8 to 25 g/m2” according to the present invention.

The SMS nonwoven fabric forming the intermediate sheet120has a higher fiber density than the top sheet110and thus has excellent liquid suction ability by capillary action. Therefore, the intermediate sheet120can quickly suck liquid excrement from the top sheet110.

As a result, the amount of liquid excrement remaining in the top sheet110can be reduced.

Therefore, it can be made hard to visually recognize the liquid excrement from the excretion surface101of the top sheet110.

The total light transmittance of the intermediate sheet120is higher than that of the top sheet110.

Under this condition, the total light transmittance of the intermediate sheet120is set to 60 to 90%. This is an example embodiment that corresponds to the feature that “the total light transmittance of the intermediate sheet is 60 to 90%” according to the present invention.

Increase of the total light transmittance of the intermediate sheet120can be realized by reducing the thickness of the intermediate sheet120, reducing the amount of titanium oxide to be added to the synthetic fibers for forming the intermediate sheet120, or reducing the fiber density of the intermediate sheet120.

The absorber140of the pet absorbent sheet100has a core layer141and a super absorbent polymer layer142that is disposed on a top of the core layer141. The core layer141is an example embodiment that corresponds to the “core layer provided in the absorber” according to the present invention.

The core layer141has a core layer top surface141A that is formed on a side facing the excretion surface101of the pet absorbent sheet100, a core layer back surface141B that is formed on a side facing the placing surface102of the pet absorbent sheet100, and a core layer side surface141C that is formed between the core layer top surface141A and the core layer back surface141B.

The core layer top surface141A, the core layer back surface141B and the core layer side surface141C are example embodiments that correspond to the “core layer top surface formed on a side of the core layer facing the excretion surface, a core layer back surface formed on a side of the core layer facing the placing surface, and a core layer side surface formed between the core layer top surface and the core layer back surface”, respectively, according to the present invention.

A laminate including the core layer141and the super absorbent polymer layer142is covered by a covering sheet143. The covering sheet143is an example embodiment that corresponds to the “covering sheet that covers at least part of the core layer top surface” according to the present invention.

In the first embodiment, the covering sheet143has a first covering sheet143A that covers a top of the core layer top surface141A. The first covering sheet143A is an example embodiment that corresponds to the “first covering sheet that covers at least part of the core layer top surface” according to the present invention.

The covering sheet143further has a second covering sheet143B that covers the core layer back surface141B, the core layer side surface141C and part of the core layer top surface141A. The second covering sheet143B is an example embodiment that corresponds to the “second covering sheet that covers at least part of the core layer back surface” according to the present invention.

Further, a portion of the second covering sheet143B which covers part of the core layer top surface141A is disposed on an excretion surface side of the first covering sheet143A disposed on the core layer top surface141A.

The core layer141may be formed of a mixture of particulate or fibrous super absorbent polymer and fluff pulp, or a mixture of particulate or fibrous super absorbent polymer, fluff pulp and thermoplastic synthetic fibers.

The super absorbent polymer layer142is formed by dispersing super absorbent polymer on the top of the core layer141.

The covering sheet143, or the first covering sheet143A and the second covering sheet143B are formed of tissue paper and provided to prevent deformation of the super absorbent polymer layer142and the core layer141.

In the first embodiment, the covering sheet143is colored and forms the coloration region130. This is an example embodiment that corresponds to the feature that “the coloration region is formed in the covering sheet” according to the present invention.

Specifically, the first covering sheet143A of the covering sheet143is colored. This is an example embodiment that corresponds to the feature that “the coloration region is formed in the first covering sheet” according to the present invention.

In the first embodiment, the top sheet110and the intermediate sheet120has a white color. Having a white color here means that a dye or a pigment is not added, or that a white dye or a white pigment is added.

On the other hand, the coloration region130is colored with black-, yellow-, orange- and/or red-based color. In this invention, the black-based color is defined as having an L* value of 50 or less in an L*a*b* color system. This is an example embodiment that corresponds to the feature that “the coloration region has an L* value of 50 or less in an L*a*b* color system” according to the present invention.

Further, in the present invention, yellow-, orange- and red-based colors are collectively defined as having an L* value larger than 0 but smaller than 100 and a b* value larger than −0.4a in the L*a*b* color system. This is an example embodiment that corresponds to the feature that “the coloration region has an L* value larger than 0 but smaller than 100 and a b* value larger than −0.4a in an L*a*b* color system” according to the present invention.

A black-based color absorbs the coloration pattern colored by liquid excrement and thereby makes the excrement inconspicuous.

Further, yellow-, orange- and red-based colors assimilate with the coloration pattern colored by liquid excrement and thereby make the excrement inconspicuous.

The back sheet160may be preferably formed particularly of a resin film sheet in order to reliably secure its liquid-impermeability. For example, a film of polyethylene, polypropylene or polyethylene terephthalate may be used to form the back sheet160. Further, in consideration of flexibility, the back sheet may also be formed of a nonwoven fabric to which a water repellent is applied.

A bonding part150is provided to bond the top sheet110and the intermediate sheet120, the intermediate sheet120and the first covering sheet143A, the first covering sheet143A and the super absorbent polymer layer142, and the top sheet110and the back sheet160.

The bonding part150includes a surface layer side bonding part151for bonding the top sheet110and the intermediate sheet120, an intermediate bonding part152for bonding the intermediate sheet120and the first covering sheet143A, an absorber side bonding part153for bonding the first covering sheet143A and the super absorbent polymer layer142, and an edge end bonding part154for bonding the top sheet110and the back sheet160.

A hot-melt adhesive is used in the surface layer side bonding part151, the intermediate bonding part152and the edge end bonding part154. The hot-melt adhesive is also referred to as HMA (Hot Melting Adhesive).

The hot-melt adhesive can be applied to the surface layer side bonding part151, the intermediate bonding part152and the edge end bonding part154in a spiral or linear pattern.

Further, the surface layer side bonding part151and the intermediate bonding part152are preferably subjected to curtain spray coating. In the curtain spray coating, the hot-melt adhesive is discharged in the form of fine fibers and uniformly applied.

In the curtain spray coating, an adhesive coating of 0.1 to 1.0 g/m2is particularly preferable. Under this condition, when the top sheet110, the intermediate sheet120and the absorber140absorb excrement, the intermediate sheet120and the absorber140are separated from each other by deformation due to expansion.

The edge end bonding part154is preferably subjected to bead coating because the top sheet110and the back sheet160must be firmly bonded together.

In the bead coating, the hot-melt adhesive is linearly applied in non-contact with the bonding part along a machine direction in the manufacturing process. Therefore, the hot-melt adhesive is applied in a fine line, so that a small amount of hot-melt adhesive can be provided with a high basis weight.

In the absorber side bonding part153, the first covering sheet143A and the super absorbent polymer layer142are bonded together by water spray. In the water spray, water is sprayed over the super absorbent polymer layer142to bond the first covering sheet143A thereto in the manufacturing process, so that deformation of the absorber can be prevented. After sprayed, the water evaporates. Thus, the water sprayed part of the pet absorbent sheet100is dry in user's actual use of the pet absorbent sheet100.

In the pet absorbent sheet100according to the first embodiment of the present invention, when a pet excretes, the excrement is led from the top sheet110into the absorber140via the intermediate sheet120. At this time, the excrement can be satisfactorily transferred to the absorber140through the intermediate sheet120having low liquid retainability. Further, the top sheet110has a lower total light transmittance than the intermediate sheet120, so that the excrement retained in the intermediate sheet120and the absorber140is made less visible from the top sheet100.

The first covering sheet143A forming the coloration region130can conceal the excrement retained in the intermediate sheet120and the absorber140.

Therefore, the excrement retained in the intermediate sheet120and the absorber140is made less visible from the top sheet100.

Further, the intermediate bonding part152that bonds the intermediate sheet120and the first covering sheet143A collapses, and the intermediate sheet120and the absorber140are separated from each other.

As a result, the excrement retained in the intermediate sheet120and the absorber140is further made less visible from the top sheet100.

Second Embodiment

A second embodiment according to the present invention is explained with reference toFIG. 4. In a pet absorbent sheet200according to the second embodiment, an absorber240is disposed between a top sheet210and a back sheet260, and an intermediate sheet220is disposed between the top sheet210and the absorber240.

The top sheet210has the same structure as the top sheet100of the first embodiment. Specifically, the top sheet210is formed of a through-air nonwoven fabric, having ridges211, grooves212which are each formed between adjacent ones of the ridges211and openings213which are formed at intervals and extend along the grooves212.

The back sheet260has the same structure as the back sheet160of the first embodiment.

The absorber240has the same structure as the absorber140of the first embodiment. Specifically, a core layer241and a super absorbent polymer layer242which is disposed on a top of the core layer241are covered by a first covering sheet243A and a second covering sheet243B.

Further, a portion of the second covering sheet243B which covers part of a core layer top surface241A is disposed on an excretion surface side of the first covering sheet243A disposed on the core layer top surface241A.

The first covering sheet243A is colored and forms a coloration region230.

In the second embodiment, the intermediate sheet220includes a first intermediate sheet221and a second intermediate sheet222. In this manner, a plurality of sheets can be used as the intermediate sheet220. Further, the first intermediate sheet221and the second intermediate sheet222are bonded by the first intermediate bonding part252A, and the second intermediate sheet222and the absorber240are bonded by the second intermediate bonding part252B.

Like the intermediate bonding part152of the above-described first embodiment, the second intermediate bonding part252B can be separated by liquid absorption.

Further, in the second embodiment, the two intermediate sheets220are used, but three or more intermediate sheets may be used. This is an example embodiment that corresponds to the feature that “a plurality of the intermediate sheets are provided” according to the present invention.

A surface layer side bonding part251has the same structure as the surface layer side bonding part151of the first embodiment.

An absorber side bonding part253has the same structure as the absorber side bonding part153of the first embodiment.

An edge end bonding part254has the same structure as the edge end bonding part154of the first embodiment.

The pet absorbent sheet200according to the second embodiment essentially has the same effect as the pet absorbent sheet100of the first embodiment.

In this embodiment, however, by providing the first intermediate sheet221and the second intermediate sheet222as the intermediate sheet220, higher concealability for excrement is provided compared with the first embodiment.

Further, the first intermediate sheet221can be provided to have higher fiber density than the top sheet210, and the second intermediate sheet222can be provided to have higher basis weight than the first intermediate sheet221.

Specifically, density gradient can be provided among the top sheet210, the first intermediate sheet221and the second intermediate sheet222. As a result, liquid can be more easily drawn into the absorber240, so that the excrement concealing effect (concealability) can be enhanced.

Third Embodiment

A third embodiment according to the present invention is explained with reference toFIG. 5. In a pet absorbent sheet300according to the third embodiment, an absorber340is disposed between a top sheet310and a back sheet360. Further, an intermediate sheet320is disposed between the top sheet310and the absorber340.

The top sheet310has the same structure as the top sheet110of the first embodiment. Specifically, the top sheet310is formed of a through-air nonwoven fabric, having ridges311, grooves312which are each formed between adjacent ones of the ridges311and openings313which are formed at intervals and extend along the grooves312.

The back sheet360has the same structure as the back sheet160of the first embodiment.

In the absorber340, a core layer341and a super absorbent polymer layer342which is disposed on a top of the core layer341are covered by a covering sheet. The covering sheet is formed of a single sheet and referred to as a third covering sheet343.

The covering sheet343is formed of colored tissue and forms a coloration region330. Thus, the coloration region330is also formed on the side of a placing surface300B of the pet absorbent sheet300.

This is an example embodiment that corresponds to the feature that “the covering sheet comprises a third covering sheet that covers the core layer back surface” according to the present invention.

The intermediate sheet320has the same structure as the intermediate sheet120of the first embodiment.

A surface layer side bonding part351has the same structure as the surface layer side bonding part151of the first embodiment.

An intermediate bonding part352has the same structure as the intermediate bonding part152of the first embodiment.

An absorber side bonding part353has the same structure as the absorber side bonding part153of the first embodiment.

An edge end bonding part354has the same structure as the edge end bonding part154of the first embodiment.

The pet absorbent sheet300according to the third embodiment has the same effect as the pet absorbent sheet100of the first embodiment in terms of concealability for excrement as viewed from the excretion surface.

Further, the coloration region330is also provided on the placing surface. Generally, when disposed of after use, a pet absorbent sheet is folded with the excretion surface inside. Accordingly, the placing surface is exposed.

Therefore, in the pet absorbent sheet300according to the third embodiment, the excrement can be made less visible from the placing surface side, so that user's discomfort can be reduced when the absorbent sheet is disposed of after use.

Fourth Embodiment

A fourth embodiment according to the present invention is explained with reference toFIG. 6.

In a pet absorbent sheet400according to the fourth embodiment, an absorber440is disposed between a top sheet410and a back sheet460. Further, an intermediate sheet420is disposed between the top sheet410and the absorber440.

The top sheet410has the same structure as the top sheet110of the first embodiment. Specifically, the top sheet410is formed of a through-air nonwoven fabric, having ridges411, grooves412which are each formed between adjacent ones of the ridges411and openings413which are formed at intervals and extend along the grooves412.

The back sheet460has the same structure as the back sheet160of the first embodiment.

In the absorber440, a core layer441and a super absorbent polymer layer442which is disposed on a top of the core layer441are covered by a first covering sheet443A and a second covering sheet443B.

Further, a portion of the second covering sheet443B which covers part of a core layer top surface441A is disposed on an excretion surface side of the first covering sheet443A disposed on the core layer top surface441A.

The first covering sheet443A and the second covering sheet443B are formed of uncolored white tissue.

The intermediate sheet420is formed of SMS nonwoven fabric like the intermediate sheet120of the first embodiment, but the intermediate sheet420is colored and forms a coloration region430.

This is an example embodiment that corresponds to the feature that “the coloration region is formed in the intermediate sheet” according to the present invention.

A surface layer side bonding part451has the same structure as the surface layer side bonding part151of the first embodiment.

An intermediate bonding part452has the same structure as the intermediate bonding part152of the first embodiment.

An absorber side bonding part453has the same structure as the absorber side bonding part153of the first embodiment.

An edge end bonding part454has the same structure as the edge end bonding part154of the first embodiment.

The pet absorbent sheet400according to the fourth embodiment has the same effect as the pet absorbent sheet100of the first embodiment.

Fifth Embodiment

A fifth embodiment according to the present invention is explained with reference toFIG. 7. In a pet absorbent sheet500according to the fifth embodiment, an absorber540is disposed between a top sheer510and a back sheet560. Further, an intermediate sheet520is disposed between the top sheet510and the absorber540.

The top sheet510is formed of a through-air nonwoven fabric, having ridges511, grooves512which are each formed between adjacent ones of the ridges511, and openings513which are formed at intervals and extend along the grooves512.

The top sheet510is colored and forms a coloration region530. This is an example embodiment that corresponds to the feature that “the coloration region is formed in the top sheet” according to the present invention.

The back sheet560has the same structure as the back sheet160of the first embodiment.

In the absorber540, a core layer541and a super absorbent polymer layer542which is disposed on a top of the core layer541are covered by a first covering sheet543A and a second covering sheet543B.

Further, a portion of the second covering sheet543B which covers part of a core layer top surface541A is disposed on an excretion surface side of the first covering sheet543A disposed on the core layer top surface541A.

The first covering sheet543A and the second covering sheet543B are formed of uncolored white tissue.

The intermediate sheet520has the same structure as the intermediate sheet120of the first embodiment.

A surface layer side bonding part551has the same structure as the surface layer side bonding part151of the first embodiment.

An intermediate bonding part552has the same structure as the intermediate bonding part152of the first embodiment.

An absorber side bonding part553has the same structure as the absorber side bonding part153of the first embodiment.

An edge end bonding part554has the same structure as the edge end bonding part154of the first embodiment.

The pet absorbent sheet500according to the fifth embodiment has the same effect as the pet absorbent sheet100of the first embodiment.

Sixth Embodiment

A sixth embodiment according to the present invention is explained with reference toFIG. 8. In a pet absorbent sheet600according to the sixth embodiment, an absorber640is disposed between a top sheet610and a back sheet660. Further, an intermediate sheet620is disposed between the top sheet610and the absorber640.

The top sheet610has the same structure as the top sheet110of the first embodiment. Specifically, the top sheet610is formed of a through-air nonwoven fabric, having ridges611, grooves612which are each formed between adjacent ones of the ridges611, and openings613which are formed at intervals and extend along the grooves612.

The back sheet560has the same structure as the back sheet160of the first embodiment.

In the absorber640, a core layer641and a super absorbent polymer layer642which is disposed on a top of the core layer641are covered by a first covering sheet643A and a second covering sheet643B.

Further, a portion of the second covering sheet643B which covers part of a core layer top surface641A is disposed on an excretion surface side of the first covering sheet643A disposed on the core layer top surface641A.

The core layer641is formed of colored pulp fibers and forms a coloration region630. This is an example embodiment that corresponds to the feature that “the coloration region is formed in the core layer” according to the present invention.

The first covering sheet643A and the second covering sheet643B are formed of uncolored white tissue.

The intermediate sheet620has the same structure as the intermediate sheet120of the first embodiment.

A surface layer side bonding part651has the same structure as the surface layer side bonding part151of the first embodiment.

An intermediate bonding part652has the same structure as the intermediate bonding part152of the first embodiment.

An absorber side bonding part653has the same structure as the absorber side bonding part153of the first embodiment.

An edge end bonding part654has the same structure as the edge end bonding part154of the first embodiment.

The pet absorbent sheet600according to the sixth embodiment has the same effect as the pet absorbent sheet100of the first embodiment.

Seventh Embodiment

A seventh embodiment according to the present invention is explained with reference toFIG. 9. A pet absorbent sheet100A according to the seventh embodiment is different from the pet absorbent sheet100of the first embodiment in the arrangement of a second covering sheet143AB.

Specifically, a portion of the second covering sheet143AB which covers part of a core layer top surface141A is disposed on an excretion surface side of the intermediate sheet120disposed on the core layer top surface141A.

The pet absorbent sheet100A according to the seventh embodiment has the same effect as the pet absorbent sheet100according to the first embodiment.

Eighth Embodiment

An eighth embodiment according to the present invention is explained with reference toFIG. 10. A pet absorbent sheet400A according to the eighth embodiment is different from the pet absorbent sheet400of the fourth embodiment in the arrangement of a second covering sheet443AB.

Specifically, a portion of the second covering sheet443AB which covers part of a core layer top surface441A is disposed on an excretion surface side of the intermediate sheet420disposed on the core layer top surface441A.

The pet absorbent sheet400A according to the eighth embodiment has the same effect as the pet absorbent sheet400according to the fourth embodiment.

Ninth Embodiment

A ninth embodiment according to the present invention is explained with reference toFIG. 11. A pet absorbent sheet500A according to the ninth embodiment is different from the pet absorbent sheet500of the fifth embodiment in the arrangement of a second covering sheet543AB.

Specifically, a portion of the second covering sheet543AB which covers part of a core layer top surface541A is disposed on an excretion surface side of the intermediate sheet520disposed on the core layer top surface541A.

The pet absorbent sheet500A according to the ninth embodiment has the same effect as the pet absorbent sheet500according to the fifth embodiment.

Tenth Embodiment

A tenth embodiment according to the present invention is explained with reference toFIG. 12. A pet absorbent sheet600A according to the tenth embodiment is different from the pet absorbent sheet600according to the sixth embodiment in the arrangement of a second covering sheet643AB.

Specifically, a portion of the second covering sheet643AB which covers part of a core layer top surface641A is disposed on an excretion surface side of the intermediate sheet620disposed on the core layer top surface641A.

The pet absorbent sheet600A according to the tenth embodiment has the same effect as the pet absorbent sheet600according to the sixth embodiment.

Eleventh Embodiment

An eleventh embodiment according to the present invention is explained with reference toFIG. 13. A pet absorbent sheet100B according to the eleventh embodiment is different from the pet absorbent sheet100of the first embodiment in the arrangement of a second covering sheet143BB.

Specifically, a portion of the second covering sheet143BB which covers part of the core layer top surface141A is disposed on a placing surface side of a first covering sheet143BA.

The pet absorbent sheet100B according to the eleventh embodiment has the same effect as the pet absorbent sheet100according to the first embodiment.

Twelfth Embodiment

A twelfth embodiment according to the present invention is explained with reference toFIG. 14. A pet absorbent sheet400B according to the twelfth embodiment is different from the pet absorbent sheet400of the fourth embodiment in the arrangement of a second covering sheet443BB.

Specifically, a portion of the second covering sheet443BB which covers part of a core layer top surface441A is disposed on a placing surface side of a first covering sheet443BA.

The pet absorbent sheet400B according to the twelfth embodiment has the same effect as the pet absorbent sheet400according to the fourth embodiment.

Thirteenth Embodiment

A thirteenth embodiment according to the present invention is explained with reference toFIG. 15. A pet absorbent sheet500B according to the thirteenth embodiment is different from the pet absorbent sheet500of the fifth embodiment in the arrangement of a second covering sheet543BB.

Specifically, a portion of the second covering sheet543BB which covers part of a core layer top surface541A is disposed on a placing surface side of a first covering sheet543BA.

The pet absorbent sheet500B according to the thirteenth embodiment has the same effect as the pet absorbent sheet500according to the fifth embodiment.

Fourteenth Embodiment

A fourteenth embodiment according to the present invention is explained with reference toFIG. 16. A pet absorbent sheet600B according to the fourteenth embodiment is different from the pet absorbent sheet600of the sixth embodiment in the arrangement of a second covering sheet643BB.

Specifically, a portion of the second covering sheet643BB which covers part of a core layer top surface641A is disposed on a placing surface side of a first covering sheet643BA.

The pet absorbent sheet600B according to the fourteenth embodiment has the same effect as the pet absorbent sheet600according to the sixth embodiment.

The structure of the absorbent sheet for pets according to the present invention is not limited to those as described above. Further, the structures according to the first to fourteenth embodiments can be appropriately applied in combination.

EXAMPLE

Example according to the present invention is shown inFIGS. 17 and 18.

The Example is used to evaluate the concealability for excrement with respect to the absorbent sheet for pets according to the present invention.

First, in preparing the Example, evaluation of total light transmittance was conducted on sheet-like members for forming the Example and Comparative Example.

For the evaluation, five sheets were obtained.

Sheet1is formed of through-air nonwoven fabric and has a basis weight of 25 g/m2.

Sheet2is formed of through-air nonwoven fabric and has a basis weight of 23 g/m2.

Sheet3is formed of through-air nonwoven fabric and has a basis weight of 20 g/m2.

Sheet4is formed of SMS (spunbond/meltblown/spunbond) nonwoven fabric and Sheet4is formed of SMS (spunbond/meltblown/spunbond) nonwoven fabric and has a basis weight of 8 g/m2.

Sheet5is formed of tissue paper and has a basis weight of 15 g/m2. The tissue paper of sheet5is colored by adding black pigment of 1% by weight.

For measurement of the total light transmittance, a test was conducted in accordance with JIS K 7015 by using a turbidimeter Z-300A of Nippon Denshoku Industries Co., Ltd. The test was carried out ten times for one sheet to find an average.

The measurement results are shown inFIG. 17.

Based on the measurement results of the total light transmittance, the sheet-like members were selected to obtain the Example and the Comparative Example.

The Example has the same structure as the pet absorbent sheet100of the first embodiment according to the present invention.

The through-air nonwoven fabric of sheet3is used as the top sheet. The SMS nonwoven fabric of sheet4is used as the intermediate sheet. The tissue paper of sheet5is used as the covering sheet.

Further, a mixture of pulp having a basis weight of 60 g/m2and super absorbent polymer is used as the absorber. A resin film sheet is used as the back sheet.

Specifically, in this Example, the top sheet has a lower total light transmittance than the intermediate sheet.

Comparative Example 1

The SMS nonwoven fabric of sheet4is used as the top sheet. The through-air nonwoven fabric of sheet3is used as the intermediate sheet. As for the covering sheet, the absorber and the back sheet, the same sheets as those in Example 1 are used.

Specifically, in this Comparative Example, the top sheet has a higher total light transmittance than the intermediate sheet.

Next, a test for evaluating the excrement concealing effect was conducted using the absorbent sheets for pets in Example 1 and Comparative Example 1.

For the test, artificial urine is first prepared by adding 0.005 g of yellow pigment No. 5 to 500 ml of common transparent artificial urine.

40 cc of the artificial urine is dropped onto each of the pet absorbent sheets of the Example and the Comparative Example. The Example and the Comparative Example are visually evaluated after an elapse of 10 seconds, 1 minute, 2 minutes and 5 minutes after dropping of the artificial urine.

In the evaluation, the color of the top sheet is rated on a scale of 1 to 10, provided that the color of the top sheet on which the artificial urine is not dropped is 1 and the color of the top sheet immediately after the artificial urine is dropped thereon is 10

This data show that the Example according to the present invention has a higher concealability for excrement than the Comparative Example.

(Correspondences Between the Features of the Embodiments and the Features of the Invention)

The pet absorbent sheets100,200,300,400,500,600,100A,400A,500A,600A,100B,400B,500B,600B are example embodiments that correspond to the “absorbent sheet for pets” according to the present invention. The excretion surface101is an example embodiment that corresponds to the “excretion surface” according to the present invention. The placing surface102is an example embodiment that corresponds to the “placing surface” according to the present invention. The top sheets110,210,310,410,510,610are example embodiments that correspond to the “top sheet” according to the present invention. The back sheets160,260,360,460,560,660are example embodiments that correspond to the “back sheet” according to the present invention. The absorbers140,240,340,440,540,640are example embodiments that correspond to the “absorber” according to the present invention. The core layers141,241,341,441,541,641are example embodiments that correspond to the “core layer” according to the present invention. The core layer top surfaces141A,241A,341A,441A,541A,641A are example embodiments that correspond to the “core layer top surface” according to the present invention. The core layer back surfaces141B,241B,341B,441B,541B,641B are example embodiments that correspond to the “core layer back surface” according to the present invention. The core layer side surfaces141C,241C,341C,441C,541C,641C are example embodiments that correspond to the “core layer side surface” according to the present invention. The covering sheets143,243,343,443,543,643,143A,443A,543A,643A,143B,443B,543B,643B are example embodiments that correspond to the “covering sheet” according to the present invention. The intermediate sheets120,220,320,420,520,620are example embodiments that correspond to the “intermediate sheet” according to the present invention. The coloration regions130,230,330,430,530,630are example embodiments that correspond to the “coloration region” according to the present invention. The ridges111,211,311,411,511,611are example embodiments that correspond to the “ridge” according to the present invention. The grooves112,212,312,412,512,612are example embodiments that correspond to the “groove” according to the present invention. The covering sheets143,243,343,443,543,643,143A,443A,543A,643A are example embodiments that correspond to the “covering sheet” according to the present invention. The first covering sheets143A,243A,343A,443A,543A,643A,143AA,443AA,543AA,643AA,143BA,443BA,543BA,643BA are example embodiments that correspond to the “first covering sheet” according to the present invention. The second covering sheets143B,243B,343B,443B,543B,643B,143AB,443AB,543AB,643AB,143BB,443BB,543BB,643BB are example embodiments that correspond to the “second covering sheet” according to the present invention. The third covering sheet343is an example embodiment that corresponds to the “third covering sheet” according to the present invention.

In view of the nature of the above-described invention, various features can be provided as follows.

An absorbent sheet for pets, comprising:

an excretion surface on which a pet excretes,

a placing surface opposite to the excretion surface,

a liquid-permeable top sheet that is disposed on the excretion surface (side),

a liquid-impermeable back sheet that is disposed on the placing surface (side),

an absorber that is disposed between the top sheet and the back sheet and absorbs liquid which has penetrated the top sheet,

a core layer that is provided in the absorber and has a core layer top surface formed on a side of the core layer facing the excretion surface, a core layer back surface formed on a side of the core layer facing the placing surface, and a core layer side surface formed between the core layer top surface and the core layer back surface,

a covering sheet that covers at least part of the core layer top surface, and

an intermediate sheet that is disposed between the top sheet and the absorber, wherein:

the absorbent sheet has a coloration region that is visible from the excretion surface side and forms a coloration pattern together with other regions of the absorbent sheet, and

the top sheet is formed to have a lower total light transmittance than the intermediate sheet.

The absorbent sheet as defined in aspect 1, wherein difference in total light transmittance between the top sheet and the intermediate sheet is 1 to 50%.

The absorbent sheet as defined in aspect 1 or 2, wherein the total light transmittance of the top sheet is 40 to 80%.

The absorbent sheet as defined in any one of aspects 1 to 3, wherein the total light transmittance of the intermediate sheet is 60 to 90%.

The absorbent sheet as defined in any one of aspects 1 to 4, wherein the top sheet has a plurality of ridges and grooves that are each formed between adjacent ones of the ridges.

The absorbent sheet as defined in any one of aspects 1 to 5, wherein the intermediate sheet comprises a composite nonwoven fabric having a meltblown nonwoven fabric layer between two spun-bond nonwoven fabric layers and having a basis weight of 8 to 25 g/m2.

The absorbent sheet as defined in any one of aspects 1 to 6, wherein the coloration region has an L* value of 50 or less in an L*a*b* color system.

The absorbent sheet as defined in any one of aspects 1 to 6, wherein the coloration region has an L* value larger than 0 but smaller than 100 and a b* value larger than −0.4a in an L*a*b* color system.

The absorbent sheet as defined in any one of aspects 1 to 8, wherein the coloration region is formed in the covering sheet.

The absorbent sheet as defined in aspect 9, wherein the covering sheet comprises a first covering sheet that covers at least part of the core layer top surface and a second covering sheet that covers at least part of the core layer back surface, and the coloration region is formed in the first covering sheet.

The absorbent sheet as defined in aspect 9, wherein the covering sheet comprises a third covering sheet that covers the core layer back surface and the coloration region is formed in the third covering sheet.

The absorbent sheet as defined in any one of aspects 9 to 11, wherein a plurality of the intermediate sheets are provided.

The absorbent sheet as defined in any one of aspects 1 to 8, wherein the coloration region is formed in the intermediate sheet.

The absorbent sheet as defined in any one of aspects 1 to 8, wherein the coloration region is formed in the top sheet.

The absorbent sheet as defined in any one of aspects 1 to 8, wherein the coloration region is formed in the core layer.

DESCRIPTION OF THE NUMERALS