JP2023013689A - Liquid absorbing nonwoven fabric laminate, lap sponge, and production method of liquid absorbing nonwoven fabric laminate - Google Patents

Abstract

To provide a liquid absorbing nonwoven fabric excellent in water absorption property and oil absorption property.SOLUTION: A liquid absorbing nonwoven fabric laminate comprises a fiber layer A comprising a cellulose-based fiber a, and a nonwoven fabric layer B comprising a fiber b comprising a thermoplastic resin.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to an absorbent nonwoven fabric laminate, a wrap sponge, and a method for producing an absorbent nonwoven fabric laminate.

A lap sponge is used as a tool for absorbing blood produced during surgery and securing a visual field.
The wrap sponge is made by laminating and sewing a plurality of gauze layers. Wrap sponges are used when they are brought into contact with bleeding sites such as internal organs of the human body to absorb blood, and many of them have a handle. Therefore, the wrap sponge is also called a patterned gauze.

For example, Patent Literature 1 describes a surgical gauze made of a fiber sheet mainly composed of solvent-spun cellulose fibers, which is used to absorb body fluids, blood, etc. during surgery.

Japanese Patent Application Laid-Open No. 2006-34507

Liquids such as body fluids and blood, particularly blood, contain a mixture of water and oil. Therefore, wrap sponges are required to have both the property of absorbing water and the property of absorbing oil. However, conventional wrap sponges and fiber sheets used for making wrap sponges do not sufficiently absorb oil, and there are cases where both water absorption and oil absorption cannot be achieved.

The present disclosure has been made in view of the above problems, and aims to provide an absorbent nonwoven fabric having excellent water and oil absorbency, a wrap sponge containing the absorbent nonwoven fabric, and a method for producing the absorbent nonwoven fabric. aim.

Means for solving the above problems include the following aspects.
<1> A fiber layer A containing cellulosic fibers a;
A nonwoven fabric layer B containing fibers b containing a thermoplastic resin;
A nonwoven fabric laminate for liquid absorption, comprising:
<2> The absorbent according to <1>, wherein at least one of the fiber layer A and the nonwoven fabric layer B is two or more layers, and the total number of layers of the fiber layer A and the nonwoven fabric layer B is three or more. Liquid nonwoven fabric laminate.
<3> The nonwoven fabric laminate for liquid absorption according to <1> or <2>, which is integrated by stitching with thread.
<4> The thread is a heat-shrinkable thread,
The nonwoven fabric laminate for liquid absorption according to <3>, wherein the laminate sewn with the heat-shrinkable thread is heat-treated.
<5> The nonwoven fabric laminate for liquid absorption according to any one of <1> to <4>, wherein the fiber layer A is located on at least one surface.
<6> The nonwoven fabric laminate for liquid absorption according to any one of <1> to <5>, wherein the thermoplastic resin contains an olefin polymer.
<7> The nonwoven fabric laminate for liquid absorption according to any one of <1> to <6>, having a thickness/basis weight of 0.035 or more when a 30 cm square is loaded with a weight of 130 g.
<8> A wrap sponge comprising the absorbent nonwoven fabric laminate according to any one of <1> to <7>.
<9> A step of obtaining a laminate by integrating a fibrous web A containing cellulosic fibers a and a fibrous web B containing fibers b containing a thermoplastic resin;
shrinking the laminate;
A method for producing a nonwoven fabric laminate for liquid absorption, comprising:
<10> The method for producing a nonwoven fabric laminate for liquid absorption according to <9>, wherein stitching is performed with a thread in the step of obtaining the laminate.
<11> The method for producing a liquid-absorbent nonwoven fabric laminate according to <10>, wherein the yarn is a heat-shrinkable yarn.
<12> The method for producing an absorbent nonwoven fabric laminate according to any one of <9> to <11>, wherein the shrinking step includes heating the laminate in an environment of 80° C. or higher. .

ADVANTAGE OF THE INVENTION According to this indication, the manufacturing method of the nonwoven fabric for liquid absorption which is excellent in water absorption and oil absorption, the lap sponge containing the said nonwoven fabric for liquid absorption, and the said nonwoven fabric for liquid absorption can be provided.

In the present disclosure, "-" indicating a numerical range is used to include the numerical values before and after it as lower and upper limits.
In the numerical ranges described step by step in the present disclosure, the upper limit or lower limit described in one numerical range may be replaced with the upper limit or lower limit of another numerical range described step by step. Also, in the numerical ranges described in the present disclosure, the upper or lower limits of the numerical ranges may be replaced with the values shown in the examples.
In the present disclosure, the term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes as long as the intended purpose of the process is achieved.
In this disclosure, when referring to the amount of each component in the composition, when there are multiple substances corresponding to each component in the composition, unless otherwise specified, the amount of the multiple substances present in the composition means total volume.

[Nonwoven fabric laminate for liquid absorption]
The absorbent nonwoven fabric laminate of the present disclosure includes a fiber layer A containing cellulosic fibers a and a nonwoven fabric layer B containing fibers b containing a thermoplastic resin. The nonwoven fabric laminate for liquid absorption of the present disclosure has excellent water absorbency due to the inclusion of the fiber layer A, and excellent oil absorption due to the inclusion of the nonwoven fabric layer B. The liquid-absorbent nonwoven fabric laminate is excellent in water absorbency and oil absorbency, and thus is suitable for use as a wrap sponge for absorbing liquid such as blood.

The liquid-absorbing nonwoven fabric laminate of the present disclosure is used for absorbing liquids, particularly liquids such as blood in which water and oil are mixed. Nonwoven fabric laminates that are not used for liquid absorption, for example, nonwoven fabric laminates for diaper topsheets (layers through which urine passes when the liquid absorbent material is absorbed) do not correspond to nonwoven fabric laminates for liquid absorption. .

Although the use of the liquid-absorbing nonwoven fabric laminate of the present disclosure is not particularly limited, it is suitably used in applications requiring water absorbency and oil absorbency. The liquid-absorbent nonwoven fabric laminate of the present disclosure is, for example, a wrap sponge used when absorbing liquid such as blood; cleaning supplies such as wipers; therapeutic supplies such as bandages and plaster; wiping supplies in kitchens, factories, etc. may be used in applications where both water absorption and oil absorption are required.

The liquid-absorbent nonwoven fabric laminate of the present disclosure is not particularly limited in layer configuration as long as at least one fiber layer A and at least one nonwoven fabric layer B are arranged in the thickness direction.

(Fiber layer A)
The nonwoven fabric laminate for liquid absorption of the present disclosure includes a fiber layer A containing cellulosic fibers a. The liquid-absorbing nonwoven fabric laminate may contain one fiber layer A, or may contain two or more fiber layers A.

When the absorbent nonwoven fabric laminate includes two or more fiber layers A, the cellulosic fibers a contained in each fiber layer A may be the same or different. Further, physical properties such as basis weight of each fiber layer A may be the same or different.

The basis weight of the fiber layer A is not particularly limited, and is preferably 40 g/m ² or more and 80 g/m ² or less, more preferably 50 g/m ² or more and 70 g/m ² or less. The basis weight after shrinkage is, for example, preferably 50 g/m ² or more and 120 g/m ² or less, more preferably 60 g/m ² or more and 80 g/m ² or less.
The method for measuring basis weight in the present disclosure is as described in Examples below.
The basis weight of the fiber layer A means the basis weight per layer.

Cellulosic fibers a contained in the fiber layer A include, for example, natural cellulose fibers such as hemp, cotton and pulp, regenerated cellulose fibers such as cupra, rayon, viscose rayon, polynosic rayon and lyocell. Among them, cotton, rayon, etc. are preferable, and cotton is preferable from the viewpoint of water absorption and touch.

Examples of cotton include absorbent cotton and non-absorbent cotton. The absorbent cotton may be bleached absorbent cotton, and the unabsorbed cotton may be bleached unabsorbed bleached cotton. The fiber layer A containing cotton as the cellulosic fiber a may be a cotton fiber web obtained by spreading and stacking cotton by a known carding method.
The fiber length of cotton is not particularly limited, and may be about 10 mm to 100 mm.

The content of the cellulosic fibers a in the fiber layer A is preferably 70% by mass or more, more preferably 90% by mass or more, relative to the total mass of the fiber layer A. The upper limit of the content of the cellulosic fibers a in the fiber layer A is not particularly limited, and may be 100% by mass or less.

The cellulosic fibers a in the fiber layer A may optionally contain commonly used additives. Additives include, for example, charging agents, antistatic agents, absorbent particles, nanoparticles, ion exchange resins, deodorants, fragrances, adhesives, surface modifiers, biocides, antibacterial agents, antiviral agents, agents, flame retardants, stabilizers, antioxidants, weather stabilizers, heat stabilizers, light stabilizers, antifog agents, lubricants, dyes, pigments, natural oils, synthetic oils, waxes, and other known additives. be done. These other components may be contained inside the cellulosic fibers a, or may adhere to the surfaces of the cellulosic fibers a.

(Nonwoven fabric layer B)
The nonwoven fabric laminate for liquid absorption of the present disclosure includes a nonwoven fabric layer B containing fibers b. The liquid absorbing nonwoven fabric laminate may contain one nonwoven fabric layer B, or may contain two or more nonwoven fabric layers B.

When the liquid-absorbent nonwoven fabric layered body includes two or more nonwoven fabric layers B, the fibers b contained in each nonwoven fabric layer B may be the same or different. Further, physical properties such as basis weight of each nonwoven fabric layer B may be the same or different.

Nonwoven fabrics constituting the nonwoven fabric layer B include spunbond nonwoven fabrics, meltblown nonwoven fabrics, wet nonwoven fabrics, spunlace nonwoven fabrics, dry nonwoven fabrics, dry pulp nonwoven fabrics, air-laid nonwoven fabrics, water jet nonwoven fabrics, flash spun nonwoven fabrics, spread nonwoven fabrics, needle-punched nonwoven fabrics, and the like. and various known nonwoven fabrics. When the nonwoven fabric layer B for liquid absorption includes two or more nonwoven fabric layers B, the two or more nonwoven fabric layers B may be composed of the same type of nonwoven fabric, or may be composed of different types of nonwoven fabric. . As the nonwoven fabric constituting the nonwoven fabric layer B, a spunbond nonwoven fabric is preferable from the viewpoints of having high oil absorbency, being easy to obtain strength, and not easily generating fiber lint, in addition to feeling and bulkiness.

The basis weight of the nonwoven fabric layer B is not particularly limited, and is preferably 10 g/m ² or more and 25 g/m ² or less, more preferably 15 g/m ² or more and 20 g/m ² or less.
In addition, the basis weight of the nonwoven fabric layer B means the basis weight per layer.

The fibers b contained in the nonwoven fabric layer B contain a thermoplastic resin. The thermoplastic resin is not particularly limited, and examples thereof include olefin-based polymers, polyester-based polymers, polyamide-based polymers, and thermoplastic resin compositions containing a plurality of these polymers. In the present disclosure, the thermoplastic resin is a concept including thermoplastic resin compositions.

An olefin polymer is a polymer mainly containing structural units derived from an olefin, a polyester polymer is a polymer containing polyester as a structural unit, and a polyamide polymer is a polymer containing polyamide as a structural unit. It is a coalescence.
In the present disclosure, "mainly containing" means that the target substance is contained in the largest amount in the whole. For example, it indicates that the content ratio of the target substance is 50% by mass or more as a percentage of the whole.

The thermoplastic resin preferably contains an olefin polymer. Olefin polymers include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene , 4-methyl-1-pentene, 4-methyl-1-hexene, and other α-olefin homopolymers or copolymers.

More specifically, the α-olefin homopolymer or copolymer includes high-pressure low-density polyethylene, linear low-density polyethylene (LLDPE), high-density polyethylene, and ethylene-olefin containing mainly ethylene-derived structural units. Ethylene-based polymers such as α-olefin copolymers, polypropylene (propylene homopolymer), propylene-based polymers such as propylene/α-olefin copolymers mainly containing structural units derived from propylene, 1-butene homopolymers Coalescing, 1-butene-based polymers such as 1-butene/α-olefin copolymers mainly containing structural units derived from 1-butene, 4-methyl-1-pentene homopolymers, 4-methyl-1-pentene Examples thereof include 4-methyl-1-pentene-based polymers such as 4-methyl-1-pentene/α-olefin copolymers mainly containing the derived structural unit. Among them, the α-olefin homopolymer or copolymer is preferably a propylene-based polymer from the viewpoint of excellent spinnability, mechanical strength, chemical resistance, and the like.

Propylene-based polymers include propylene homopolymers and propylene/α-olefin copolymers. The propylene-based polymer may contain both a propylene homopolymer and a propylene/α-olefin copolymer. The α-olefin used for the copolymerization of the propylene/α-olefin copolymer is preferably an α-olefin having 2 or more carbon atoms (excluding propylene), more preferably an α-olefin having 2 or 4 to 8 carbon atoms. Specific examples of α-olefins include ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1 -pentene, 4-methyl-1-pentene, 4-methyl-1-hexene and the like are preferred.

Specific examples of the propylene/α-olefin copolymer include a propylene/ethylene copolymer and a propylene/ethylene/1-butene copolymer.

In the propylene/α-olefin copolymer, the content of structural units derived from α-olefin is preferably 1 mol% to 10 mol% of the whole, and 1 mol% to 5 mol% of the whole. is more preferred.

The melting point (Tm) of the propylene-based polymer is preferably 120°C or higher, more preferably 125°C to 165°C.
In the present disclosure, melting point is measured as follows.
(1) A propylene-based polymer was set in a measurement pan for differential scanning calorimetry (DSC) manufactured by PerkinElmer, heated from 30°C to 200°C at a rate of 10°C/min, and held at 200°C for 10 minutes. After that, the temperature is lowered to 30°C at a rate of 10°C/min.
(2) Next, the temperature is again raised from 30° C. to 200° C. at a rate of 10° C./min, and the melting point is determined from the peaks observed during that time.

The melting point (Tm) of the propylene homopolymer is preferably 155°C or higher, more preferably 157°C to 165°C.
The melting point (Tm) of the propylene/α-olefin copolymer is preferably 120°C to 155°C, more preferably 125°C to 150°C.

The melt flow rate (MFR) of the propylene-based polymer (MFR: ASTM D-1238, 230° C., load 2160 g) is not limited as long as it is melt-spinnable, and is 20 g/10 minutes to 100 g/10 minutes. preferably 30 g/10 minutes to 80 g/10 minutes. When the MFR of the propylene-based polymer is 100 g/10 minutes or less, the mechanical strength of the fiber b tends to be excellent. When the MFR of the propylene-based polymer is 20 g/10 minutes or more, there is a tendency that fiber breakage during draw spinning can be suppressed.

The fibers b contained in the nonwoven fabric layer B may be monocomponent fibers containing one thermoplastic resin, or composite fibers containing two or more thermoplastic resins. The bicomponent fibers may be, for example, side-by-side, concentric core-sheath or eccentric core-sheath. The eccentric core-sheath type conjugate fiber may be an exposed type in which the core is exposed on the surface, or may be a non-exposed type in which the core is not exposed on the surface.

When the conjugate fiber is a core-sheath type, the mass ratio of the sheath to the core (core/sheath) is, for example, preferably 95/5 to 5/95, preferably 90/10 to 10/ It is more preferably 90, more preferably 60/40 to 10/90.

The fiber b is preferably a conjugate fiber containing a propylene-based polymer, more preferably a crimped conjugate fiber containing a propylene-based polymer, and an eccentric core-sheath type crimped conjugate containing a propylene-based polymer. Fibers are more preferred.

The fibers b may be monocomponent fibers or composite fibers as described above, or may be crimped fibers, hollow fibers, elastic fibers, or the like.

The average fiber diameter of the fibers b is preferably in the range of 5 μm to 30 μm. The upper limit of the average fiber diameter is more preferably 25 μm or less, still more preferably 20 μm or less.
The method for measuring the average fiber diameter in the present disclosure is as described in Examples below.

The fibers b contained in the nonwoven fabric layer B may contain commonly used additives as needed. Additives include, for example, hydrophilic agents, static charge agents, antistatic agents, absorbent particles, nanoparticles, ion exchange resins, deodorants, fragrances, adhesives, surface modifiers, biocides, and antibacterial agents. , antiviral agents, flame retardants, stabilizers, antioxidants, weather stabilizers, heat stabilizers, light stabilizers, anti-fogging agents, lubricants, dyes, pigments, natural oils, synthetic oils, waxes, etc. agents. These other components may be contained inside the fiber b or attached to the surface of the fiber b.

The liquid-absorbent nonwoven fabric laminate of the present disclosure may include two or more layers of at least one of the fiber layer A and the nonwoven fabric layer B, and the total number of layers of the fiber layer A and the nonwoven fabric layer B may be three or more. In this case, the arrangement of the fiber layer A and the nonwoven fabric layer B is not particularly limited. For example, the fiber layer A and the nonwoven fabric layer B may be alternately laminated, or the fiber layer A and the nonwoven fabric layer B may be randomly laminated. may

The total number of layers of the fiber layer A and the nonwoven fabric layer B is not particularly limited as long as it is 2 or more, and may be, for example, 3-8 or 4-6.

In the nonwoven fabric laminate for liquid absorption of the present disclosure, it is preferable that the fiber layer A is positioned on at least one surface from the viewpoint of water absorption. The absorbent nonwoven fabric laminate may have the fiber layer A on one surface and the nonwoven fabric layer B on the other surface, or may have the fiber layers A on both surfaces.

The nonwoven fabric laminate for liquid absorption of the present disclosure may include layers other than the fiber layer A and the nonwoven fabric layer B. Other layers include knitted fabrics, woven fabrics, films, papers, and the like.

The liquid-absorbent nonwoven fabric laminate of the present disclosure is preferably integrated by stitching with threads. The stitching shape is not particularly limited as long as the fiber layer A, the nonwoven fabric layer B, etc. are integrated. For example, the surface of the liquid-absorbent nonwoven fabric laminate is observed, and spaced apart along at least one direction such as the longitudinal direction, the lateral direction, and the direction crossing the longitudinal and lateral directions of the liquid-absorbent nonwoven fabric laminate. Sutures with threads may be performed, and sutures with threads are performed at intervals along two intersecting directions such as the longitudinal direction and the lateral direction (for example, suturing in a grid pattern). good too. Alternatively, stitching may be performed concentrically, such as concentric circles, concentric squares, etc., or may be performed radially. or may be sewn symmetrically with respect to a line segment parallel to the surface of the nonwoven fabric laminate for liquid absorption and passing through the center of the surface.

The seam pitch for sewing is not particularly limited, and is preferably 2.0 mm to 6.0 mm, more preferably 2.5 mm to 5.0 mm. When the seam pitch is 2.0 mm or more, when the liquid-absorbent nonwoven fabric laminate is produced by heat-shrinking the fiber layer A, etc., the liquid-absorbent nonwoven fabric laminate tends to be prevented from becoming too hard. . When the seam pitch is 6.0 mm or more, it tends to be possible to increase the bulk of the liquid-absorbent nonwoven fabric laminate when the fiber layer A or the like is thermally shrunk to produce the liquid-absorbent nonwoven fabric laminate. .

The seam pitch by sewing may be appropriately changed depending on the total number of layers (preferably the total number of the fiber layer A and the nonwoven fabric layer B; the same shall apply hereinafter) contained in the nonwoven fabric laminate for liquid absorption. For example, when the total number of layers contained in the liquid-absorbent nonwoven fabric laminate is 2 to 5, preferably 2 to 4, the seam pitch is preferably 2.0 mm to 6.0 mm, preferably 2.5 mm to 2.5 mm. 5.0 mm is more preferable. When the total number of layers contained in the nonwoven fabric laminate for liquid absorption is 5 to 8, preferably 6 to 8, the seam pitch is preferably 3.0 mm to 6.0 mm, more preferably 3.5 mm to 5.0 mm. 0 mm is more preferable.

The distance between seams that are adjacent in a certain direction such as the vertical direction or the horizontal direction, or the distance between seams that are adjacent concentrically or the like is not particularly limited, and is preferably 2.0 cm to 10 cm. More preferably, it is between 0.0 cm and 8.0 cm. When the distance between the seams is 2.0 cm or more, the liquid-absorbing nonwoven fabric layered body tends to be suppressed from becoming too hard when the liquid-absorbing non-woven fabric layered body is produced by thermally shrinking the fiber layer A or the like. It is in. When the distance between the seams is 10.0 cm or more, it tends to be possible to make the liquid-absorbent nonwoven fabric layered body bulky when the liquid-absorbent non-woven fabric layered body is produced by thermally shrinking the fiber layer A or the like. It is in.

Threads used for suturing may be heat-shrinkable threads or non-shrinkable threads that do not shrink due to heat. When the fiber layer A or the like is thermally shrunk to produce a nonwoven fabric laminate for liquid absorption, the fiber layer A and the nonwoven fabric layer B are deformed by the shrinkage of the threads, and a bulky liquid absorption nonwoven fabric layered body is obtained from the viewpoint that: Threads used for suturing are preferably heat-shrinkable threads. Further, the liquid-absorbent nonwoven fabric laminate of the present disclosure is preferably formed by heat-treating a laminate stitched with a heat-shrinkable thread.

The heat-shrinkable yarn is not particularly limited as long as it is shrunk by heating and, if necessary, cooling, and examples thereof include unstretched polyester.

In the liquid-absorbent nonwoven fabric laminate of the present disclosure, the thickness when a 30 cm square and a load of 130 g weight is applied (hereinafter also referred to as "thickness under low load") is preferably 5 mm to 18 mm, More preferably, it is between 8 mm and 15 mm.
A method for measuring the thickness under a low load in the present disclosure is as described in Examples below.

In the nonwoven fabric laminate for liquid absorption of the present disclosure, the thickness under load is preferably 1 mm to 5 mm, more preferably 2 mm to 4 mm.
The method of measuring the thickness with a load in the present disclosure is as described in Examples below.

^The basis weight of the liquid ^- absorbent ^nonwoven fabric ^laminate of the present disclosure is not particularly limited. more preferred.

In the liquid-absorbing nonwoven fabric laminate of the present disclosure, the thickness/basis weight at low load is preferably 0.035 or more, more preferably 0.035 to 0.08, and more preferably 0.039 to 0.068. is more preferable. When the thickness/basis weight at low load is 0.035 or more, the liquid-absorbent nonwoven fabric laminate tends to be bulky and has excellent cushioning properties, and when the liquid-absorbent nonwoven fabric laminate is applied to a wrap sponge. , there is a tendency to suppress stimulation when the wrap sponge is brought into contact with the bleeding site.
In addition, in thickness/basis weight at low load, the unit of thickness at low load is mm, and the unit of basis weight is g/m ² .

The nonwoven fabric laminate for liquid absorption of the present disclosure may be obtained by heat-treating or washing the laminate containing the fiber layer A and the nonwoven fabric layer B, and stitching with threads (preferably heat-shrinkable threads). The laminate may be heat-treated or washed with water. As a result, the liquid-absorbing nonwoven fabric laminate tends to be excellent in bulkiness due to shrinkage of the fiber layer A and the like, and can be suitably applied as a wrap sponge. The nonwoven fabric laminate for liquid absorption of the present disclosure may be a laminate containing the fiber layer A and the nonwoven fabric layer B that has shrunk, or a laminate containing the fiber layer A and the nonwoven fabric layer B that has shrunk. good too.

Examples of the heat treatment include a method of heating the laminate in an oven. Examples of the water washing treatment include a method of washing the laminate with water and then drying it.

For the heat-treated liquid-absorbing nonwoven fabric laminate of the present disclosure, the thickness at low load is preferably 30% to 200% higher than the thickness at low load of the laminate before heat shrinkage. % to 150% bulk is more preferred. As the heat treatment, for example, the laminate may be placed in an oven at 110° C. for 5 minutes.
In addition, as to whether the laminated body sewn with the thread is a heat-treated laminated body that has already been heat-treated or an untreated laminated body that has not been heat-treated, the target laminated body is subjected to heat treatment, It may be estimated from the rate of change in thickness under low load before and after the heat treatment. If the thickness under low load after heat treatment is 30% or more bulkier than the thickness before heat treatment, the target laminate may be presumed to be an untreated laminate. If the thickness under low load after heat treatment is less than 30% larger than the thickness before heat treatment, the target laminate may be presumed to be a heat-treated laminate.

[Wrap Sponge]
The wrap sponge of the present disclosure includes the absorbent nonwoven fabric laminate of the present disclosure described above. Since the liquid-absorbent nonwoven fabric laminate of the present disclosure is excellent in water absorption and oil absorption, the wrap sponge of the present disclosure is suitably used for absorbing liquids, particularly liquids such as blood in which water and oil are mixed. .

[Method for manufacturing nonwoven fabric laminate for liquid absorption]
The manufacturing method of the liquid-absorbent nonwoven fabric laminate of the present disclosure includes a step of integrating a fibrous web A containing cellulosic fibers a and a fibrous web B containing fibers b containing a thermoplastic resin to obtain a laminate; and shrinking the laminate. By this manufacturing method, the nonwoven fabric laminate for liquid absorption of the present disclosure described above can be manufactured. The nonwoven fabric laminate for liquid absorption of the present disclosure is not limited to one manufactured by this manufacturing method.
Moreover, the preferred conditions for the liquid-absorbent nonwoven fabric laminate of the present disclosure may be applied as the preferred conditions for the method for producing the liquid-absorbent nonwoven fabric laminate.

The manufacturing method of the nonwoven fabric laminate for liquid absorption of the present disclosure includes a step of integrating a fiber web A and a fiber web B to obtain a laminate.

The fiber web A may be a fiber assembly containing cellulosic fibers a. The fiber web A may be, for example, a fiber assembly containing natural cellulose fibers such as hemp, cotton, pulp, cupro, rayon, viscose rayon, polynosic rayon, and regenerated cellulose fibers such as lyocell.

For example, when the cellulosic fiber a is cotton, the fiber web A may be a cotton fiber web obtained by spreading and stacking cotton by a known carding method. The fibrous web A may be cotton gauze or the like.

The fiber web B may be a fiber assembly containing fibers b containing a thermoplastic resin. For example, the fibrous web B uses a thermoplastic resin as a raw material, and uses known manufacturing methods such as an air-through method, a spunbond method, a needle punch method, a meltblown method, a card method, a heat fusion method, a hydroentanglement method, and a solvent bonding method. It may be a nonwoven web manufactured by

For example, fibrous web B is preferably a spunbond nonwoven web produced by the spunbond process. Spunbond nonwoven webs are produced, for example, by melt spinning a thermoplastic resin to form continuous fibers and depositing the continuous fibers onto a moving collection member. If desired, the spunbond nonwoven web may be partially pressed by an embossing roll or the like.

When laminating the fibrous web A containing the cellulosic fibers a and the fibrous web B containing the fibers b, at least one layer of the fibrous web A and at least one layer of the fibrous web B may be laminated.

When laminating the fibrous web A and the fibrous web B, even if at least one of the fibrous web A and the fibrous web B has two layers or more and the total number of layers of the fibrous web A and the fibrous web B is three or more. good. In this case, the arrangement of the fiber web A and the fiber web B is not particularly limited. For example, the fiber web A and the fiber web B may be alternately laminated, or the fiber web A and the fiber web B may be randomly laminated. may

The total number of layers of the fiber web A and the fiber web B is not particularly limited as long as it is 2 or more, and may be, for example, 3-8 or 4-6.

When laminating the fibrous web A and the fibrous web B, it is preferable that the fibrous web A is positioned on at least one surface from the viewpoint of water absorption in the liquid-absorbent nonwoven fabric laminate to be produced. Furthermore, the fiber web A may be positioned on one surface and the fiber web B may be positioned on the other surface, or the fiber web A may be positioned on both surfaces.

At least one layer of the fiber web A and at least one layer of the fiber web B are integrated using a known method such as a chemical bond method, a thermal bond method, a needle punch method, a spunlace method, a stitch bond method, etc. to form a laminate. may be formed. A needle punch method and a spunlace method are preferable from the viewpoint of promoting the permeation of the liquid when absorbing the liquid. Moreover, from the viewpoint of suppressing the dropping of fibers, a spunlace method, a thermal bond method, a chemical bond method, and the like are preferable.

In the step of obtaining the laminate, stitching with thread may be performed. For example, the laminate may be obtained by arranging at least one layer of the fiber web A and at least one layer of the fiber web B in the thickness direction and then stitching them with threads. Preferable conditions such as the shape of the stitches, the seam pitch of the stitches, the distance between the seams, etc. are the same as those for the liquid-absorbent nonwoven fabric laminate of the present disclosure described above.

After subjecting at least one layer of the fiber web A and at least one layer of the fiber web B to a known method such as the above-described chemical bonding method, the above-described fiber web A and the fiber web are sewn with threads. B may be integrated to obtain a laminate.

Alternatively, after a part of the fiber web A and the fiber web B constituting the laminate are integrated by a known method such as the chemical bonding method described above, the whole is integrated and laminated by sewing with threads. You can get a body

For example, when the layer structure of the laminate is fiber web A (A1)/nonwoven web B (B1)/nonwoven web A (A2)/nonwoven web B (B2), A1 and B1 are After integrating by the bonding method or the like and integrating A2 and B2 by the chemical bonding method or the like described above, the integrated A1 and B1 and the integrated A2 and B2 are overlapped, and then sewn together. A laminate may also be used. Alternatively, after integrating A1, B1 and A2 by the chemical bonding method or the like described above, the integrated A1, B1 and A2, and the single layer B2 are stacked, and then stitched to form a laminate. good.

As described above, a laminate including the fiber layer A derived from the fiber web A and the nonwoven fabric layer B derived from the fiber web B is obtained.

Threads used for suturing are preferably heat-shrinkable threads. By using a heat-shrinkable yarn, the fiber layer A and the nonwoven fabric layer B tend to be deformed due to the shrinkage of the yarn due to the heat treatment when shrinking the laminate, resulting in a bulky nonwoven fabric laminate for liquid absorption. .

The manufacturing method of the nonwoven fabric laminate for liquid absorption of the present disclosure includes a step of shrinking the laminate. Examples of the treatment for shrinking the laminate include heat treatment and water washing treatment for the laminate. Heat treatment is preferable from the viewpoint of obtaining a bulky nonwoven fabric laminate for liquid absorption.

Examples of the heat treatment include a method of heating the laminate in an oven. Examples of the water washing treatment include a method of washing the laminate with water and then drying it.

The heat treatment temperature may be any temperature at which the cellulosic fiber a and the fiber b containing a thermoplastic resin do not dissolve, decompose, or ignite, and may be 80°C or higher, or even 90°C to 150°C. It may be 100°C to 130°C.
The heat treatment time may be, for example, 1 minute to 30 minutes or 3 minutes to 10 minutes.

When the thread used for sewing is a heat-shrinkable thread, it is preferable to shrink the layered body by heat-treating the layered body. At this time, the temperature of the heat treatment may be at least the temperature at which the heat-shrinkable yarn shrinks and at which the cellulosic fiber a and the fiber b containing the thermoplastic resin do not dissolve, decompose, or ignite. It may be appropriately set according to the material of the shrinkable thread. When the heat-shrinkable yarn is undrawn polyester or the like, the temperature of the heat treatment preferably satisfies the above temperature conditions.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded.

[Example 1]
(Preparation of spunbond nonwoven fabric)
As a raw material for the spunbond nonwoven fabric, a propylene homopolymer having a melting point of 162° C. and an MFR (measured according to ASTM D1238 at a temperature of 230° C. and a load of 2160 g; hereinafter, unless otherwise specified), and a propylene homopolymer of 60 g/10 min and a melting point of 142 °C, an MFR of 60 g/10 min, an ethylene-derived structural unit content of 4.0 mol%, and a propylene-derived structural unit content of 96.0 mol%. .

Using these raw materials, a spunbond nonwoven fabric was produced by the spunbond method.
Specifically, the core is made of a propylene homopolymer, the sheath is made of a propylene/ethylene random copolymer, and the mass ratio of the sheath to the core (core/sheath) is 20 by composite melt spinning. A crimped conjugate fiber with a ratio of /80 was obtained. The obtained crimped conjugated fibers were deposited on a collection surface, and then the deposited crimped conjugated fibers were embossed under the conditions of an embossed area ratio of 18% and an embossing temperature of 110° C. to obtain a basis weight of 18 g/m. No. ² spunbond nonwoven fabric was obtained. In the obtained spunbond nonwoven fabric, the average fiber diameter of the crimped conjugate fibers was 16 μm. Specifically, the crimped conjugate fibers contained in the spunbond nonwoven fabric were eccentric core-sheath type crimped conjugate fibers and had a side-by-side cross-sectional shape.

(Production of wrap sponge)
Two sheets of spunbonded nonwoven fabric were prepared from the spunbonded nonwoven fabric produced above, and two sheets of cotton gauze (100% cotton, manufactured by Suzuran Co., Ltd., basis weight 60 g/m ² ) were prepared. A laminate was prepared by laminating cotton gauze/spunbond nonwoven fabric/cotton gauze/spunbond nonwoven fabric in this order. Using an electric sewing machine (manufactured by Brother) and thread (manufactured by Onuki Textile Co., Ltd., polyester heat shrinkable thread, No. 40), the warp and weft are made into a plurality of squares (length of one side) at a seam pitch of 2.5 mm. 5.0 cm).

The sewn laminate was placed on a metal tray and placed in an air oven at 110°C for 5 minutes. After standing still, it was taken out from the air oven to obtain a wrap sponge. The layer structure of the lap sponge is cotton gauze/spunbond nonwoven fabric/cotton gauze/spunbond nonwoven fabric. When referring to the layer structure in the following examples, comparative examples, and Table 1, "C" is used for cotton gauze, and "S" is used for spunbond nonwoven fabric.

[Example 2]
A wrap sponge was produced in the same manner as in Example 1, except that the layer structure of the wrap sponge in Example 1 was changed to the layer structure shown in Table 1.

[Example 3]
A wrap sponge was produced in the same manner as in Example 1, except that the stitch pitch was changed to 4.0 mm.

[Example 4]
A wrap sponge was produced in the same manner as in Example 1 except that the layer structure in Example 1 was changed to the layer structure shown in Table 1.

[Example 5]
A wrap sponge was produced in the same manner as in Example 4, except that the stitch pitch was changed to 4.0 mm.

[Example 6]
A wrap sponge was produced in the same manner as in Example 1, except that the thread used for sewing in Example 1 was changed to a non-shrinkable Schappespun polyester thread (60 count) manufactured by Fujix.

[Example 7]
A wrap sponge was produced in the same manner as in Example 4, except that the thread used for sewing in Example 4 was changed to a non-shrinkable Schappespun polyester thread (60 count) manufactured by Fujix.

[Comparative Example 1]
Four sheets of cotton gauze (100% cotton, manufactured by Suzuran Co., Ltd., basis weight 60 g/m ² ) were prepared. A laminate was prepared by stacking four sheets of cotton gauze in order. Using an electric sewing machine (manufactured by Brother) and thread (manufactured by Fujix Co., Ltd., polyester non-heat shrinkable thread, No. 60), the warp and weft are made into a plurality of squares (length of one side) at a seam pitch of 2.5 mm. 5.0 cm).

After the sewn laminate was immersed in hot water at 100°C for 5 minutes, it was exposed to hot air at 110°C for 15 minutes and dried to obtain a wrap sponge. The layer structure of the lap sponge is C/C/C/C.

[Comparative Examples 2 and 3]
A wrap sponge was produced in the same manner as in Example 1 except that the layer structure in Example 1 was changed to the layer structure shown in Table 1.

[Comparative Example 4]
A wrap sponge was produced in the same manner as in Comparative Example 2, except that the stitch pitch was changed to 4.0 mm.

The spunbond nonwoven fabric and lap sponge thus obtained were subjected to the following measurements and evaluations. Table 1 shows the results.

(1) Average fiber diameter (μm)
Ten rectangular test pieces each having a length of 10 mm and a width of 10 mm were taken from the spunbond nonwoven fabric. Each sample sample was imaged with a Nikon ECLIPSE E400 microscope at a magnification of 300 times. The diameter of all fibers visible in the image and visible in diameter was measured in microns to one decimal place. The imaging and measurement were repeated until the number of fibers whose diameters were measured reached 50 or more. The average value of the diameters of 50 or more fibers obtained was calculated as the average fiber diameter.

(2) basis weight (g/m ² )
Five 10 cm square rectangular samples were taken from the wrap sponge, spunbond nonwoven fabric, or cotton gauze. The basis weight was determined by dividing the total mass of the five samples taken by the total area of the five samples.

(3) Thickness at low load (mm)
Five 30 cm square samples were collected using the same samples as in the measurement of basis weight described above. The thickness of a total of 5 points was measured using a low-load thickness gauge (measured by applying a load of 130 g using a square metal flat plate with a side of 30 cm as the contact surface). The arithmetic mean value of the obtained measured values was defined as the thickness (mm) of the wrap sponge under low load.

(4) Thickness with load (mm)
Five samples were taken in the same manner as the basis weight measurement described above. The thickness of each sample was measured at a total of 5 points in the center and four corners using a thickness gauge (using a load of 7 gf/cm ² and a circular terminal of 25 mmφ). The arithmetic mean value of the obtained measured values was defined as the thickness (mm) of the wrap sponge with a load.

(5) Water absorption (g)
Five 100 mm long by 100 mm wide square samples were taken from the wrap sponge. A total amount of 500 ml of tap water was dropped from a height of 10 cm to each of the collected samples. After dropping, the central part of the sample was pinched with tweezers, and after standing still in the air for 10 seconds, the mass of the sample was measured. The obtained measured value was converted into a 30 cm square and taken as the water absorption amount (g).
Furthermore, the water absorption amount (g) per basis weight was determined by dividing the obtained water absorption amount (g) by the basis weight (g/m ² ) of the wrap sponge.

(6) Oil absorption (g)
Five 100 mm long by 100 mm wide square samples were taken from the wrap sponge. A vat was prepared, and the inside of the vat was filled with Gurley test machine oil (Eneos, product number “Super Oil T Grade 10”, ISO viscosity grade: VG-10).
Each sample taken was immersed in the oil in the vat for 10 seconds. After the immersion, the central part of the sample was pinched with tweezers, and after standing still in the air for 1 minute, the mass of the sample was measured. The obtained measured value was converted into a 30 cm square to obtain an oil absorption (g).
Furthermore, the oil absorption (g) per basis weight was determined by dividing the obtained oil absorption (g) by the basis weight (g/m ² ) of the wrap sponge.

As shown in Table 1, the wrap sponges of Examples 1-7 were superior to the wrap sponges of Comparative Examples 1-4 in water absorption and oil absorption.

Claims (12)

A fiber layer A containing cellulosic fibers a;
A nonwoven fabric layer B containing fibers b containing a thermoplastic resin;
A nonwoven fabric laminate for liquid absorption, comprising: 2. The nonwoven fabric for liquid absorption according to claim 1, comprising two or more layers of at least one of the fiber layer A and the nonwoven fabric layer B, and the total number of layers of the fiber layer A and the nonwoven fabric layer B being three or more. laminate. 3. The nonwoven fabric laminate for liquid absorption according to claim 1 or 2, which is integrated by stitching with thread. The thread is a heat-shrinkable thread,
4. The nonwoven fabric laminate for liquid absorption according to claim 3, wherein the laminate stitched with the heat-shrinkable thread is heat-treated. The nonwoven fabric laminate for liquid absorption according to any one of claims 1 to 4, wherein the fiber layer A is located on at least one surface. The nonwoven fabric laminate for liquid absorption according to any one of claims 1 to 5, wherein the thermoplastic resin contains an olefin polymer. 7. The nonwoven fabric laminate for liquid absorption according to any one of claims 1 to 6, wherein the thickness/basis weight is 0.035 or more when a 30 cm square is loaded with a weight of 130 g. A wrap sponge comprising the absorbent nonwoven fabric laminate according to any one of claims 1 to 7. a step of integrating a fibrous web A containing cellulosic fibers a and a fibrous web B containing fibers b containing a thermoplastic resin to obtain a laminate;
shrinking the laminate;
A method for producing a nonwoven fabric laminate for liquid absorption, comprising: 10. The method for producing a nonwoven fabric laminate for liquid absorption according to claim 9, wherein in the step of obtaining the laminate, stitching is performed with thread. 11. The method for producing a liquid-absorbent nonwoven fabric laminate according to claim 10, wherein the yarn is a heat-shrinkable yarn. The method for producing a liquid-absorbent nonwoven fabric laminate according to any one of claims 9 to 11, wherein the shrinking step includes heating the laminate in an environment of 80°C or higher.