JP2017002420A - Liquid absorbing sheet and liquid absorbing roll - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid absorbing sheet hardly forming gaps between liquid absorbing sheets, high in compressibility and excellent in water absorption property in the liquid absorbing roll formed by overlapping many disc-like liquid absorbing sheets.SOLUTION: A liquid sheet containing nonwoven fabrics of a hollow fiber with long fiber and a polymer elastic body added to gap of the nonwoven fabrics and having 20% strength of 20 kg/2.5 cm or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a liquid absorbent sheet used for liquid absorption or liquid supply, in particular, an improvement of a liquid absorbent sheet preferably used for manufacturing a liquid absorbent roll for liquid absorption or liquid supply while rotating with respect to a member to be treated. About.

  Conventionally, in a manufacturing process of an article, a method using an absorbent roll is known as a method of removing excess liquid after a process of cleaning the surface of an article or a part or applying a chemical to the surface. It has been.

  For example, in Patent Document 1 below, a fiber sheet in which a porous material is filled in a porous structure in a void portion of a nonwoven mat in which lotus root-like porous fibers or ultrafine fiber bundles are entangled three-dimensionally is used as a roller surface. A liquid-absorbing roller formed by coating and adhering to is disclosed. In addition, the non-woven mat is obtained by mixing and spinning two or more kinds of polymer substances having different solubility in a solvent, cutting the resulting mixed fiber into a tow shape or an appropriate length, and then entangled three-dimensionally. It is disclosed that it is formed by.

  Further, for example, Patent Document 2 below discloses a long fiber entanglement including a hydrophilic ultra-thin fiber in which a nonwoven fabric is made of a polyamide-based fiber in a roll in which a large number of disk-like materials made of a nonwoven fabric made of synthetic fibers are superimposed. Disclosed is a non-woven roll characterized in that it is composed of coalescence.

  Further, for example, Patent Document 3 below is characterized in that, in a liquid absorbent roll composed of a roll shaft and a liquid absorbent member around the roll shaft, the liquid absorbent member is composed of a nonwoven fabric made of ultrafine fibers subjected to hydroentanglement treatment. A liquid absorption roll is disclosed. And since the liquid absorbing member has been subjected to hydroentanglement treatment, the fibers are sufficiently entangled three-dimensionally without special processing using a polymer substance. Also discloses that it has very good strength.

  As disclosed in Patent Documents 1 to 3, a liquid-absorbing sheet containing a nonwoven fabric made of ultrafine fibers has been conventionally known. A liquid-absorbing sheet including a nonwoven fabric made of such ultrafine fibers absorbs liquid by a capillary phenomenon in a gap formed between the ultrafine fibers, and holds the liquid.

Japanese Utility Model Publication No. 50-10012 JP 2004-028162 A JP-A-8-159658

  A liquid-absorbing roll is formed by stacking a large number of disc-shaped liquid-absorbing sheets containing a nonwoven fabric and making them adhere to each other so as to be compressed from both sides and forming into a roll shape. In such a liquid absorbent roll, if the liquid absorbent sheets are too hard, they may not adhere sufficiently to each other, and a gap may be formed between the liquid absorbent sheets. Such a gap has a problem in that it becomes impossible to form a contact surface having uniform water absorption, because the water absorption is reduced at that portion. In addition, when the liquid absorbent sheet is too hard, the flexibility of the liquid absorbent sheet is lowered, the contact property with respect to the member to be treated is lowered, and the water absorption is lowered.

  The present invention provides a liquid-absorbing sheet having a high compressibility and excellent water absorption, in which a gap is not easily formed between liquid-absorbing sheets in a liquid-absorbing roll formed by superimposing a large number of disc-shaped liquid-absorbing sheets. For the purpose.

  The liquid-absorbing sheet of the present invention is a liquid-absorbing sheet containing a long-fiber hollow fiber nonwoven fabric and a polymer elastic body imparted to the voids of the nonwoven fabric and having a 20% strength of 20 kg / 2.5 cm or less. Such a liquid-absorbing sheet is a liquid-absorbing sheet that includes a long-fiber hollow fiber non-woven fabric fixed with a polymer elastic body and exhibits higher water absorption due to hollow hollow fibers. Further, when the 20% strength is 20 kg / 2.5 cm or less, in the liquid absorbent roll formed by superimposing a large number of liquid absorbent sheets, it is excellent in compressibility in which gaps are not easily formed between the liquid absorbent sheets, and A supple liquid-absorbing sheet can be obtained.

The ratio of the weight (g) of the polymer elastic body to the total surface area (m ² ) of the hollow fiber is preferably 0.6 to 1.4 (g / m ² ). When a liquid absorption roll using a liquid absorbent sheet containing a nonwoven fabric made of ultrafine fibers is rotated and brought into contact with the member to be treated, there is a problem that the ultrafine fibers are cut and fallen into a fluff shape. In order to solve such a problem, when the fiber diameter of the ultrafine fiber is increased, the liquid absorbency is lowered. In addition, two or more kinds of polymer materials disclosed in Patent Document 1 of the prior art are mixed and spun, and the obtained mixed fiber is cut into a tow shape or an appropriate length to make a short fiber. According to the lotus root-like porous fiber formed by entanglement, it is suppressed to some extent that the ultrafine fiber is cut, but the short fiber is easy to fall off because the fiber length is short. In the liquid-absorbing sheet according to the present invention, the ratio of the weight (g) of the polymer elastic body to the total surface area (m ² ) of the hollow fibers is 0.65 to 1.4 (g / m ² ). Since the polymer elastic body firmly fixes the hollow fiber to the extent that it does not cover the surface of the hollow fiber, it is possible to suppress the dropping of the fiber without inhibiting the water absorption by the hollow of the hollow fiber.

  In addition, when the hollow fiber is a polyester fiber, even when water is absorbed, the resin itself does not absorb water and the rigidity is not significantly reduced unlike the polyamide fiber. Deformation due to can be suppressed.

  The polyester fiber is preferably a polybutylene terephthalate fiber from the viewpoint of easily increasing the liquid absorbency with a low apparent density.

  Moreover, when the hollow fiber is a fiber manufactured by selectively removing island components from the composite-spun sea-island type composite fiber, it is preferable from the viewpoint of higher liquid absorbency. In addition, for example, when a hollow fiber formed by mixing and spinning two or more kinds of polymer substances having different solubility is used, the liquid absorbency tends to be lowered.

  In addition, the polymer elastic body is preferably a polyurethane derived from an aqueous polyurethane emulsion from the viewpoint of excellent water absorption.

Further, the apparent density of the liquid absorbent sheet is preferably 0.2 to 0.5 g / cm ³ from the viewpoint of excellent liquid absorbency.

  Further, the liquid absorption roll of the present invention is a liquid absorption roll for absorbing the liquid adhering to the member to be processed or supplying the liquid to the member to be processed. It is a liquid-absorbing roll which is formed into a disk-like sheet having a through hole in the center, and is compressed and fixed by superposing a large number of the through holes through the core material. In such a liquid-absorbing roll, a highly compressible disc-shaped sheet is compressed and closely adhered. Therefore, it is possible to obtain a liquid-absorbing roll having a high liquid-absorbing property that is difficult to form a gap between the disk-shaped sheets.

  According to the present invention, it is difficult to form a gap between the disk-shaped sheets, and a liquid-absorbing roll having high liquid absorbency is obtained.

FIG. 1 is a schematic view of a liquid absorbent sheet according to an embodiment of the present invention when enlarged. FIG. 2 is a schematic view of a liquid absorption roll according to an embodiment of the present invention. Fig.3 (a) is explanatory drawing which shows a mode that the clearance gap between the liquid absorption rolls 120 provided with the liquid absorption sheet 110 too hard outside the range of this invention is formed, FIG.3 (b) concerns on this invention. It is explanatory drawing which shows a mode that the clearance gap between the liquid absorption rolls 20 provided with the liquid absorption sheet 10 was suppressed. FIG. 4 is a schematic diagram for explaining the fluff removal evaluation of the example.

  An embodiment of a liquid-absorbing sheet and liquid-absorbing roll according to the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic diagram when the liquid absorbent sheet 10 of the present embodiment is viewed in an enlarged manner. The liquid-absorbing sheet 10 includes a nonwoven fabric 1 in which long-fiber hollow fibers 1 a are three-dimensionally entangled and a polymer elastic body 2 applied to the voids of the nonwoven fabric 1. Moreover, the liquid absorbing sheet 10 maintains a 20% strength of 20 kg / 2.5 cm or less.

  First, the hollow fiber will be described in detail. The resin forming the hollow fiber is not particularly limited, and specifically, polyesters such as polybutylene terephthalate (PBT) and polyethylene terephthalate (PET); polyamides such as polyamide 6; polyolefins such as polypropylene and polyethylene; or these Examples include modified products. These may be used alone or in combination of two or more. Among these, in the case of polyester-based fibers containing polyester as a main component, the resin itself does not absorb water and the rigidity does not significantly decrease like polyamide-based fibers. In this case, it is preferable because deformation of the liquid absorption roll can be suppressed. In addition, since the polyester fiber is a polybutylene terephthalate fiber, it is less susceptible to thermal shrinkage in the production process than the polyethylene terephthalate fiber, so that it is possible to obtain a nonwoven fabric that has a low apparent density and is easy to absorb liquid. preferable.

  The resin forming the hollow fiber may contain a colorant such as a dye or pigment, an ultraviolet absorber, a heat stabilizer, a deodorant, a fungicide, various stabilizers, and the like as necessary.

The fiber diameter of the hollow fiber is not particularly limited, but is 0.5 × 10 ^{−3 to} 5.0 × 10 ⁻³ (cm), and further 1.0 × 10 ^{−3 to} 4.0 × 10 ⁻³ (cm). It is preferable that When the fiber diameter is too large, the suppleness of the liquid-absorbing sheet is lowered, and the contact property with respect to the member to be processed tends to be lowered. Further, when the fiber diameter is too small, the fiber density tends to be too high and the liquid absorbency tends to decrease.

The apparent density of the hollow fiber is not particularly limited, but is 0.30 to 1.4 g / cm ³ , further 0.40 to 1.1 g / cm ³ , particularly 0.50 to 1.0 g / cm ^3. It is preferable from the standpoint that sufficient shape stability can be maintained while sufficiently securing a hollow for maintaining liquid absorbency. When the apparent density of the hollow fibers is too high, the water absorption of the liquid absorbent sheet tends to decrease. Moreover, when the apparent density of a hollow fiber is too low, there exists a tendency for the shape stability of a liquid absorbing sheet to fall.

  Furthermore, the hollow ratio of the hollow fiber is preferably 25 to 70% by volume, and more preferably 30 to 60% by volume. When the hollow ratio of the hollow fiber is too high, the shape stability tends to decrease, and when it is too low, the water absorption tends to decrease.

  Although the hollow hole diameter of a hollow fiber is not specifically limited, It is preferable that it is about 1-10 micrometers. The number of hollows in the cross section of the hollow fiber is not particularly limited, but is preferably 5 to 50, more preferably 10 to 30. If the number of hollows is too small, the liquid absorbing property of the liquid absorbing sheet tends to be lowered. Moreover, when there are too many hollow numbers, there exists a tendency for the rigidity of a fiber to fall and to deform | transform easily when it uses for a liquid absorption roll.

  The hollow fibers used in the present embodiment are continuous long fibers that are distinguished from short fibers. Specifically, the long fiber means that it is not a short fiber cut by a predetermined length. The length of the long fiber is preferably 100 mm or more, and more preferably 200 mm or more. Although an upper limit is not specifically limited, For example, the fiber length of several m, several hundreds m, several km or more spun continuously may be sufficient. By being such a long fiber, dropping of the fiber can be suppressed.

  The nonwoven fabric is a nonwoven fabric in which long hollow fibers are entangled three-dimensionally. Such a nonwoven fabric is formed, for example, by selectively removing a resin component that forms an island component from a three-dimensional entangled body of sea-island type composite fibers, as will be described later.

While the apparent density of the nonwoven fabric is not particularly limited, 0.05 to 0.5 g / cm ^3, further, 0.1 to 0.4 g / cm ^3, in particular is 0.2 to 0.3 g / cm ³ Is preferable from the standpoint that a sufficient space for maintaining liquid absorbency can be secured. When the apparent density of the nonwoven fabric is too high, the water absorption of the liquid absorbent sheet tends to decrease. Moreover, when the apparent density of a nonwoven fabric is too low, there exists a tendency for the shape stability of a liquid absorbing sheet to fall.

  As shown in FIG. 1, a polymer elastic body 2 is provided in the voids existing inside the nonwoven fabric 1.

  The resin forming the polymer elastic body is not particularly limited, and specific examples thereof include, for example, polyurethane, polyvinyl chloride, polyamide, polyester, polyester ether copolymer, polyacrylate copolymer, neoprene, styrene butadiene copolymer, and silicone resin. , Polyamino acids, polyamino acid polyurethane copolymers and the like. These may be used alone or in combination of two or more. Among these, polyurethane is particularly preferable from the viewpoint of obtaining a soft texture. In addition, the polymer elastic body may contain pigments, dyes, crosslinking agents, fillers, plasticizers, various stabilizers, and the like as necessary.

  Moreover, as a polymer elastic body, when it is a hydrophilic polymer elastic body, it is preferable from the point which is excellent in the absorptivity of water. Specific examples of such hydrophilic polymer elastic bodies include water-based polyurethanes such as polycarbonate polyurethanes, polyester polyurethanes, polyether polyurethanes, and polycarbonate / ether polyurethanes that are prepared into emulsions. . Such water-based polyurethane is usually non-porous.

  The liquid absorbent sheet of this embodiment has a 20% strength of 20 kg / 2.5 cm or less. 20% strength is obtained by obtaining a stress-strain curve according to JIS L1096 8.12.1 “Tensile strength test” using a 2.5 cm × 16 cm test piece cut out from the original sheet of the absorbent sheet. -Stress at 20% elongation obtained from the strain curve, and measure the warp direction and the transverse direction of the original fabric three by three, and take the average value thereof. The 20% strength of the liquid-absorbing sheet of the present embodiment is 20 kg / 2.5 cm or less, preferably 18 kg / 2.5 cm or less, and more preferably 16 kg / 2.5 cm or less. When the 20% strength exceeds 20 kg / 2.5 cm, the compressibility and flexibility are lowered. The lower limit of 20% strength is not particularly limited, but is preferably 3 kg / 2.5 cm, more preferably 5 kg / 2.5 cm. If the 20% strength is too low, the form stability tends to decrease.

In the liquid-absorbing sheet of the present embodiment, the polymer elastic body has a ratio U / S (g / m ² ) of the polymer elastic body weight U (g) to the total surface area S (m ² ) of the hollow fiber. 0.6 to 1.4, more preferably 0.65 to 1.3, and particularly preferably 0.7 to 1.2. When the polymer elastic body is contained in such an amount, the fibers adhere to the surface of the hollow fiber forming the non-woven fabric at an appropriate interval and the fibers are less likely to fall off, and higher water absorption is maintained. Can do. When the ratio U / S of the polymer elastic body weight U (g) to the total surface area S (m ² ) of the hollow fiber is less than 0.6 (g / m ² ), it is in contact with the member to be processed while rotating. When used in such a liquid-absorbing roll, the fibers tend to drop off when contacting the substrate to be treated while rotating. Further, when the ratio U / S exceeds 1.4 (g / m ² ), the liquid absorption tends to be reduced due to a decrease in voids necessary for liquid absorption.

As the amount of elastic polymer, the ratio of the total surface area S of the hollow fiber (m ²⁾ for the high molecular elastic weight of U (g) (g / m 2) , for example, can be calculated as follows.

The total surface area S (m ² ) of the hollow fibers contained in the original sheet of the liquid-absorbing sheet having a unit area (1 m ² ) (hereinafter also simply referred to as the original sheet) is the fiber diameter of the hollow fibers as E (cm). When the weight per unit area of the hollow fiber is M (g / m ² ) and the apparent density of the hollow fiber is C (g / cm ³ ),
It is calculated | required from following formula (1): S (m < ² >) = (4M * 10 < ^-4 >) / CE ... (1).

Equation (1) is derived as follows.
When the total fiber length of the hollow fibers contained in the original fabric of the unit area (1 m ² ) is L (cm) and the circumference of the hollow fibers is R (cm), it is included in the original fabric of the unit area (1 m ² ) The total surface area S (m ² ) of the hollow fiber is
S (m ² ) = L (cm) × R (cm) × 10 ⁻⁴ .
Moreover, when the volume of the hollow fiber contained in the raw material of the unit area (1 m ² ) is V (cm ³ ) and the cross-sectional area of the hollow fiber is D (cm ² ), the total fiber length L (cm) is
L (cm) = V (cm ³ ) / D (cm ² ).

Here, the volume V (cm ³ ) of the hollow fiber contained in the raw material of the unit area (1 m ² ) is the weight M (g / m ² ) of the hollow fiber and the apparent density C (g / cm ³ ) of the hollow fiber. And V (cm ³ ) = M (g / m ² ) / C (g / cm ³ ). Moreover, the cross-sectional area D (cm ² ) of the hollow fiber becomes D (cm ² ) = (E / 2) ² × π if the fiber diameter E (cm) of the hollow fiber is used, and the circumference R of the hollow fiber (M) is R (cm) = E (cm) × π. Therefore, the total fiber length L (cm) is
L (cm) = V (cm ³ ) / D (cm ² ) = M / C / D = M / CD. Therefore, the total surface area S (m ² ) of the hollow fiber is
S (m ² ) = L (cm) × R (cm) × 10 ⁻⁴ = MR × 10 ⁻⁴ / CD.
Furthermore, from R (cm) = E (cm) × π and D (cm ² ) = (E / 2) ² × π, S (m ² ) = {M × E (cm) × π × 10 ⁻⁴ } / {C × (E / 2) ² × π}, and S (m ² ) = (4M × 10 ⁻⁴ ) / CE (1) is derived.

On the other hand, the polymer elastic body weight U contained in the raw material of the unit area (1 m ² ) is:
Polymer elastic body weight U (g / m ² ) = raw fabric weight G (g / m ² ) × polymer elastic body ratio P The polymer elastic body ratio P is the weight ratio of the polymer elastic body in the total amount of the raw fabric.

The ratio of the total surface area S of the hollow fiber (m ²⁾ for the high molecular elastic weight of U (g) (g / m 2) is calculated by ^{U (g / m 2) /} S (m 2 / m 2) Is done.

  The thickness of the liquid absorbent sheet is not particularly limited, but is preferably 0.3 to 3 mm, and more preferably 0.7 to 1.8 mm. If the thickness of the liquid-absorbing sheet is too thin, the liquid-absorbing property tends to be insufficient, and if it is too thick, an aqueous emulsion is used to impregnate the nonwoven fabric with a polymer elastic body during production. Since it takes a long time to dry, the productivity tends to be inferior.

The apparent density of the liquid absorbent sheet is preferably 0.1 to 0.6 g / cm ³ , more preferably 0.2 to 0.5 g / cm ³ . When the apparent density of the liquid absorbing sheet is too high, the liquid absorbing property tends to be lowered.

  Next, an example of the manufacturing method of the liquid absorption sheet of this embodiment is demonstrated in detail. In the method for producing a liquid-absorbing sheet according to the present embodiment, first, the resin that forms the hollow fiber as described above is used as a sea component, and can be selectively removed with a chemical or physical property different from that of the resin that serves as the sea component. Sea-island type composite fiber with resin as island component is manufactured. And the web of the long fiber of such a sea-island type composite fiber is formed.

  A long fiber web of sea-island type composite fibers is formed using, for example, a so-called spunbond method. Specifically, a resin for forming a sea component and a resin for forming a selectively removable island component are melt composite-spun to obtain a sea-island type composite fiber strand. Subsequently, after the obtained strands of sea-island type composite fibers are cooled by a cooling device, they are drawn by a high-speed air flow at a speed corresponding to a take-up speed of 1000 to 6000 m / min, for example, by a suction device such as an air jet nozzle. Then, sea-island type composite fibers are obtained. Then, a long fiber web is obtained by depositing the sea-island type composite fiber on a collecting surface such as a movable net while opening the sea-island type composite fiber.

  The sea-island type composite fiber is composed of a resin for forming a sea component and a resin for forming a selectively removable island component having a different chemical or physical property from the resin for forming a sea component. It is a long-fiber composite fiber having a sea-island cross section. And the hollow fiber which has as a main component the resin for forming a sea component is formed by selectively removing resin of an island component from such a sea-island type composite fiber.

  Examples of the resin for forming the sea component include various resins that form hollow fibers as described above. In addition, resin for forming a sea component has a tendency for 20% strength to become low, so that the melt viscosity is low. The melt viscosity is appropriately selected according to the characteristics of the liquid-absorbing sheet to be obtained. For example, in the case of PBT, when a capillary rheometer is used and the barrel (die) temperature is 270 ° C. and the shear rate is 1000 (1 / s). Furthermore, it is preferably 50 to 300 (Pa · s), more preferably 60 to 250 (Pa · s).

  As the removable resin forming the island component, the resin forming the sea component is different from the resin forming the sea component in terms of solubility in a solvent or decomposing agent and having low compatibility with the resin forming the sea component. Any resin that can be melt-spun can be used without particular limitation. Specific examples of such a resin include, for example, a water-soluble thermoplastic polyvinyl alcohol resin (hereinafter, also simply referred to as “PVA”), polystyrene having different solvent solubility from the resin forming the sea component, and ethylene propylene copolymer. Examples thereof include a copolymer, an ethylene vinyl acetate copolymer, a styrene ethylene copolymer, and a styrene acrylic copolymer. Among these, PVA is particularly preferable because the outer wall and the partition wall forming the hollow are not easily broken. Furthermore, PVA is preferable from the viewpoint of low environmental load. In this embodiment, the case where PVA is used as a sea component will be described in detail as a representative example.

  PVA is polyvinyl alcohol that can be dissolved in hot water by saponifying a polymer containing a vinyl ester unit derived from a fatty acid vinyl ester monomer and another copolymer unit included as necessary. can get.

  Specific examples of the fatty acid vinyl ester monomer include, for example, vinyl formate, vinyl acetate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl pivalate, and versatha. Examples thereof include vinyl tick acid.

  Further, specific examples of the monomer that forms other copolymer units included as necessary include, for example, α-olefins having 4 or less carbon atoms such as ethylene, propylene, 1-butene, and isobutene; methyl vinyl ether , Vinyl ethers such as ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether, and the like. Of these, ethylene is particularly preferred. As a content rate of the other copolymerization unit in PVA, it is preferable to contain 1-20 mol%, further 4-15 mol%, especially 6-13 mol%.

  As PVA, a modified PVA obtained by saponifying a polymer mainly containing vinyl ester units derived from vinyl acetate containing 4 to 15 mol%, further 6 to 13 mol% of ethylene units is commonly used. This is particularly preferable from the viewpoint of excellent polymerizability, melt spinnability and water solubility of the fiber.

  The degree of polymerization of PVA is preferably 200 to 500, more preferably 230 to 470, and particularly preferably 250 to 450 from the viewpoint of excellent melt spinning stability and dissolution / removability to hot water.

In addition, the said polymerization degree (P) means the viscosity average polymerization degree measured according to JIS-K6726. Specifically, after re-saponification and purification of PVA, the intrinsic viscosity [η] measured in water at 30 ° C. is obtained by the following formula.
P = ([η] 10 ³ /8.29) ^{(1 / 0.62)}

  The degree of saponification of PVA is from 90 to 99.99 mol%, more preferably from 93 to 99.98 mol%, especially from 94 to 99.97 mol%, in particular from 96 to 99.96 mol%. Preferably there is. If the degree of saponification is too low, melt spinnability tends to decrease or water solubility tends to decrease.

  The melting point (Tm) of PVA is preferably 160 to 230 ° C, more preferably 170 to 227 ° C, particularly 175 to 224 ° C, and more preferably 180 to 220 ° C. When the melting point is too low, the thermal stability of PVA is lowered, and thus fiberization tends to be difficult. Further, when the melting point is too high, the melting point and the decomposition temperature are close to each other, so that there is a tendency that stable spinning cannot be performed.

  The melting point of PVA is that when DSC is used, the temperature is raised to 300 ° C. in nitrogen at a heating rate of 10 ° C./min, cooled to room temperature, and then heated again to 300 ° C. at a heating rate of 10 ° C./min It means the temperature at the peak top of the endothermic peak indicating the melting point of PVA.

  PVA is obtained by radical polymerization using a bulk polymerization method, a solution polymerization method, a suspension polymerization method, an emulsion polymerization method, or the like. Among these, a bulk polymerization method in which polymerization is performed without solvent and a solution polymerization in which polymerization is performed in a polar solvent such as alcohol are preferably used. Specific examples of the polar solvent used in the solution polymerization include lower alcohols such as methyl alcohol, ethyl alcohol, and propyl alcohol. Specific examples of radical polymerization initiators include azo initiators such as a, a′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethyl-valeronitrile), Examples thereof include peroxide initiators such as benzoyl oxide and n-propyl peroxycarbonate. Moreover, although superposition | polymerization temperature is not specifically limited, For example, the range of 0-150 degreeC is mentioned.

  In the melt composite spinning, the number of islands is preferably 5 to 50 islands / fiber cross section, more preferably 10 to 30 islands / fiber cross section.

  Furthermore, the ratio of the resin for forming the island component in the sea-island composite fiber is preferably 25 to 60% by mass, and more preferably 30 to 55% by mass. When the ratio of the resin for forming the island component is too high, the ratio of the formed hollow tends to be too high, and when it is too low, the ratio of the formed hollow tends to be too low. .

  The strand of the sea-island type composite fiber formed by melt composite spinning is cooled by a cooling device, and then corresponds to a take-up speed of 1000 to 6000 m / min so as to achieve a desired fineness using a suction device such as an air jet nozzle. Stretched by a high speed air stream. In addition, since the crystal orientation of the fiber is relaxed as the spinning speed is low, the 20% strength tends to be low. Then, the stretched sea-island type composite fibers are deposited on the movable collection surface to form a long fiber web. At this time, the long fiber web may be partially crimped as necessary.

  The fineness of the sea-island type composite fibers is preferably in the range of 0.7 to 10 dtex, and more preferably in the range of 2.5 to 8 dtex, from the viewpoint of excellent island component removability.

  Moreover, it is preferable from the point of stability of the hollow structure of the hollow fiber obtained that the fineness of the island part which forms a sea-island type composite fiber is 0.5-5 dtex, Furthermore, it is the range of 2-5 dtex.

The basis weight of the long fiber web is preferably in the range of ^{20 to} 50 g / m ² from the viewpoint of excellent productivity.

  Next, two or more long fiber webs obtained as described above are overlapped and subjected to needle punching to form a three-dimensional entangled body. This step is a step of obtaining a three-dimensional entangled body in which fibers are entangled in the thickness direction by superimposing a plurality of long fiber webs and then performing an entanglement process by needle punching. The number of long fiber webs to be overlapped is not particularly limited, but is preferably 4 or more, and more preferably 8 or more.

  A three-dimensional entangled body is formed by performing an entanglement process by needle punching on an overlapped body obtained by overlapping a plurality of long fiber webs.

  The type of felt needle used for needle punching is not particularly limited. In order to sufficiently increase the entanglement of the fibers in the thickness direction, it is preferable to use a thin felt needle or a felt needle with few barbs such as a 1 barb needle. Moreover, it is preferable to use felt needles, such as 3 barb, 6 barb, and 9 barb, from the point which suppresses cutting | disconnection of a sea-island type composite fiber.

Further, the number of felt needles used in needle punching per unit area is not particularly limited, but a range of 200 to 2500 / cm ² is preferable.

The basis weight of the three-dimensional entangled body thus obtained is preferably in the range of 100 to 3000 g / m ² , more preferably 200 to 1000 g / m ² .

  Next, after impregnating the three-dimensional entangled body with an emulsion or solution of a polymer elastic body, the polymer elastic body is solidified.

  Specific examples of the polymer elastic body include, for example, polyurethane, acrylic elastic body, silicone elastic body, diene elastic body, nitrile elastic body, fluorine elastic body, polystyrene elastic body, polyolefin elastic body, and polyamide. System elastic body, halogen-based elastic body and the like. These may be used alone or in combination of two or more. Among these, polyurethane is preferable from the viewpoint of excellent wear resistance and mechanical properties.

  As the polyurethane, water-based polyurethanes such as polycarbonate-based polyurethanes, polyester-based polyurethanes, polyether-based polyurethanes, and polycarbonate / ether-based polyurethanes prepared in an emulsion are preferable from the viewpoint of excellent compatibility with water-based liquids.

  The method of impregnating the three-dimensional entangled body with an emulsion or solution of a polymer elastic body is not particularly limited, but for example, a method of impregnating the three-dimensional entangled body with a polymer elastic body emulsion by dip-nip is preferable. Used. Then, after impregnating the emulsion of the polymer elastic body into the three-dimensional entangled body, the polymer elastic body is solidified in the gaps between the fibers of the three-dimensional entangled body by drying and removing the water in the emulsion. To do. Although drying conditions are not specifically limited, For example, the conditions of making it dry for about 1 to 10 minutes at 70-150 degreeC are mentioned. In this way, a polymer elastic body can be imparted to the gap between the fibers of the three-dimensional entangled body.

The ratio of the polymer elastic body to the three-dimensional entangled body is appropriately adjusted in consideration of water absorption, but the ratio of the weight (g) of the polymer elastic body to the total surface area (m ² ) of the hollow fiber as described above. It is preferable to adjust so that (g / m < ² >) may be 0.6-1.4. The amount of the polymer elastic body imparted to the three-dimensional entangled body is adjusted by the solid content concentration of the emulsion of the polymer elastic body and the pickup rate of the emulsion with respect to the three-dimensional entangled body.

  Examples of the method of impregnating the three-dimensional entangled body with an emulsion or solution of a polymer elastic body include a method using a knife coater, a bar coater, or a roll coater, or a dipping method.

  And the nonwoven fabric which consists of hollow fibers is formed by melt | dissolving and removing the resin of an island component from sea island type composite fiber. In this step, it is preferable to remove all or most (for example, 95% or more) of the resin forming the island component contained in the sea-island composite fiber.

  Dissolve island component resin such as PVA from sea-island type composite fiber forming three-dimensional entangled body by treating the three-dimensional entangled body with polymer elastic body in hot water containing surfactant Remove.

  In the case of PVA, examples of the hot water treatment include a method of treating at a water temperature of 80 to 95 ° C. using a dyeing machine such as a liquid dyeing machine or a jigger, or a scouring machine such as an open soaper. In particular, in order to improve the removal efficiency, it is preferable to use a liquid flow dyeing machine that can physically deform the hollow fiber, or a device that combines a vibro washing machine and a squeezing device in multiple stages.

  When processing using a dyeing machine such as a liquid dyeing machine or a jigger, or a scouring machine such as an open soaper, the 20% strength of the liquid-absorbing sheet obtained varies greatly depending on the tension applied to the original fabric. In order to obtain the liquid-absorbing sheet according to the present invention, it is preferable to process without relatively applying tension. In this step, if too much tension is applied, the fibers forming the nonwoven fabric tend to be stretched and the 20% strength tends to be too high. The tension applied to the raw material that is continuously conveyed can be adjusted by, for example, a load applied to the dancer roll.

  In addition, nonionic surfactants such as poly (oxyethylene) alkyl ethers that improve the wettability of sea component resins and known anionic surfactants to improve the removal efficiency of island component resins It is preferable to use hot water containing an agent. As such a surfactant, the HLB (Hydrophile-Lipophile Balance) is preferably in the range of 4-16.

  And after removing all or most of resin of island components, such as PVA, contained in a sea-island type composite fiber, the original fabric of the liquid absorbing sheet of this embodiment is obtained by drying.

  The raw fabric of the liquid absorbent sheet of the present embodiment thus obtained is used as a liquid absorbent sheet after being subjected to a slicing process or a forming process for cutting into a target shape, if necessary.

  The liquid absorbent sheet of this embodiment is preferably used for various applications where liquid absorption or liquid supply processing is required. In particular, a liquid adhering to the member to be processed, formed into a disk-shaped sheet having a through-hole in the center, formed by passing through-holes through a core material and overlapping them in a moderately compressed state. It is preferably used for a use of a liquid absorption roll for absorbing liquid or supplying liquid to a member to be treated. In such a liquid absorbent roll, a highly compressible disc-shaped sheet is compressed and adhered to such an extent that the water absorption is not reduced. Accordingly, a liquid-absorbing sheet in which a gap is not easily formed between the disk-shaped sheets can be obtained.

  FIG. 2 is a schematic perspective view for explaining a state of using a liquid absorbent roll 20 formed by superposing a large number of liquid absorbent sheets 10 formed on a disk-shaped sheet according to this embodiment. 5 is a core material, 6 is a fixing ring, 11 is a water droplet, 15 is a member to be processed which is conveyed in the direction of a white arrow, and 15a is a convex shape formed on the member 15 to be processed. Part. As shown in FIG. 2, the liquid absorbent roll 20 is a state in which a disk-shaped sheet-shaped liquid absorbent sheet 10 having a through hole in the center is appropriately compressed by passing a through hole through the core material 5 and superposing a large number of sheets. Thus, the fixing ring 6 is used for fixing. The liquid-absorbing roll 20 absorbs water droplets 11 by contacting the surface of the member to be treated 15 while being supported in the direction of an arrow while being supported by rotating means (not shown) around the core material 5 as a rotation axis. To do. Such a liquid absorbent roll 20 has a long life because, for example, the fibers are not easily dropped even when the portion 15a of the convex shape of the processed member 15 and the end face of the water absorbent sheet are rubbed. It is also excellent in water absorption.

  As shown in FIG. 3A, in the case of the liquid absorbent roll 120 including the liquid absorbent sheet 110 that is too hard, the liquid absorbent sheets 110 are difficult to adhere to each other, so that a gap is easily formed between the liquid absorbent sheets 110. In addition, when the suppleness is poor, the contact with the member to be processed is lowered. On the other hand, as shown in FIG.3 (b), in the case of the liquid absorption roll 20 provided with the liquid absorption sheet 10 whose 20% strength which concerns on this invention is 20 kg / 2.5cm or less, the liquid absorption sheet 10 itself expands and contracts. In order to be rich in properties, when a large number of sheets are superposed and compressed and fixed, the liquid absorbent sheets 10 are pressed against each other and are in close contact with each other, so that a gap is not easily formed between the liquid absorbent sheets 10. Moreover, since it is excellent in flexibility, it is excellent also in the contact property with respect to a to-be-processed member. Therefore, uniform water absorption can be realized.

  EXAMPLES The present invention will be described more specifically with reference to examples, but the present invention is not limited to the examples. First, the measurement method and the evaluation method used in this example will be described together.

[20% stronger]
A stress-strain curve was obtained according to JIS L1096 8.12.1 “Tensile Strength Test” using a 2.5 cm × 16 cm test piece cut out from the raw sheet of the obtained liquid-absorbing sheet. And the stress when it extended 20% from a stress-strain curve was read, and 20% strength was calculated | required. In the test, three warp directions and three transverse directions of the original fabric were measured, and the average value thereof was 20% stronger than the liquid absorbent sheet.

[Measurement of fiber diameter E of hollow fiber]
The cross section of the original sheet of the liquid-absorbing sheet was observed with an electron microscope at a magnification of 800 times, the diameter of an arbitrary fiber cross section was measured at five points, and the average value was defined as the fiber diameter E. The cross-sectional diameter of an arbitrary fiber was obtained by measuring and measuring the longest diameter and the shortest diameter.

[Measurement of apparent density of liquid absorbent sheet]
The apparent density (g / cm ³ ) was obtained by dividing the mass (g / cm ² ) per unit area of the original sheet of the liquid-absorbing sheet by the thickness (cm). The result is the arithmetic average value of the apparent density measured for any 10 locations. The thickness was measured under a load of 240 gf / cm ² according to JISL1096.

[Compression rate]
In accordance with JIS L 1096, a liquid-absorbing sheet was set at an autograph gripping interval of 10 mm, compressed to a compression load of 4.0 kg / cm ² at a compression speed of 3 mm / min, and left as it was for 1 minute. Thereafter, the sample was deweighted at a speed of 3 mm / min, left for 3 minutes, and compressed again at a speed of 3 mm / min until it exceeded 0.25 kg / cm ² . The amount of strain when the load was compressed to 4.0 kg / cm ² was L, the amount of strain when the load was released and the strain returned to a constant amount was a, and the compression rate was calculated as a / L × 100 (%).

[C hardness]
According to JIS K 6253-3, the surface hardness of the liquid absorbent sheet was measured at three points, and the average was calculated.

[Water absorption test]
The liquid absorbent sheet is cut into a size of 4 cm (vertical) × 10 cm (wide), the weight is measured, and the original is immersed in an aluminum vat containing 1 L of distilled water at 20 ° C. It was taken out after 24 hours, the original fabric was placed on a filter paper, excess moisture was removed, the weight was measured, and the water absorption was calculated by the following formula.
Water absorption (%) = (weight after immersion−weight before immersion) / weight before immersion × 100

[Fuzz removal evaluation]
Fluff removal evaluation was performed using a Taber abrasion measuring machine 31 as shown in FIG. Specifically, the raw material of the obtained liquid-absorbing sheet is formed into a disc-shaped sheet with a diameter of 40 mm having a through-hole with a diameter of 15 mm in the center, and the through-hole is penetrated through an iron core material to have a thickness of about A 6 mm weight body was produced. Then, the weight body was impregnated with water so that the pickup rate was 150%. Then, as shown in FIG. 4, the weight body 30 of the disk-like sheet impregnated with water is attached to the Taber abrasion measuring machine 31, and is brought into contact with the cloth 32 with a total load of 500 g and rotated 500 times on the surface. The attached fluff adhesion state was visually determined according to the following criteria.
First grade: The fluff was attached in the form of a completely dark ring having the same width as the thickness of the weight body.
Second grade: Fluff was attached in a complete but thin ring shape.
Third grade: The circumference was partially interrupted, and fuzz was attached so as to form more than half of the circumference.
Grade 4: Fluff was attached so as to form less than half of the circumference.
Grade 5: Fluff was attached so as to form less than a quarter of the circumference.
Grade 6: Fluff was not attached.

[Example 1]
A sea-island type composite fiber strand of 12 islands containing polybutylene terephthalate (PBT) as a sea component and water-soluble thermoplastic PVA as an island component and having a mass ratio of sea component / island component of 50/50 is melted at 265 ° C. The product was discharged from a composite spinning nozzle. As PBT, NOVADURAN 5010 manufactured by Mitsubishi Engineering Plastics Co., Ltd. (melt viscosity [temperature 270 ° C., shear rate 1000 ⁻¹ ] 150 Pa / s) and as water-soluble thermoplastic PVA manufactured by Kuraray Co., Ltd. Exval CP-4104MI ( Melting point: 209 ° C., MFR measured by M method of JIS K7210: 80 g / min, viscosity average polymerization degree 330, saponification degree 98.4 mol%).

The resin discharged from the die was cooled while being stretched and thinned by an air jet suction device installed directly below the die, thereby spinning a sea-island type composite fiber having an average fineness of 2.66 dtex. The suction force of the air jet suction device was adjusted so that the spinning speed obtained indirectly from the ratio of the discharge amount per unit time and the fineness of the obtained long fibers was 2250 m / min. Then, the sea-island type composite fibers are continuously collected on a mobile net installed directly under the air jet suction device, and are pressed using a metal roll having a surface temperature of 80 ° C., whereby long fibers having a basis weight of 35 g / m ² . Got the web.

The long fiber webs were overlapped with a cross wrapper so as to have a basis weight corresponding to 14 sheets. Moreover, the needle breakage prevention oil agent was uniformly given to the long fiber web surface using a spray. Next, by performing a needle punching process so that the total number of needles pierced alternately on both sides of the long fiber web is 1390 / cm ² , the entangled long fiber webs are entangled with each other, whereby the basis weight is 595 g / m ^2. The three-dimensional entanglement was obtained.

  Next, a polyurethane impregnating solution (solid content concentration: 12.3% by mass) was prepared by adding a carbodiimide-based crosslinking agent and ammonium sulfate to an aqueous emulsion of non-yellowing polycarbonate-based polyurethane which is a polymer elastic body. The three-dimensional entangled body was impregnated with a polyurethane impregnating solution by dipping and niping so that the pickup rate was 200% by mass. Thereafter, the film was dried at 110 ° C. in a 30% RH atmosphere, further dried with hot air at 100 ° C. for 30 minutes in a dryer, and then cured at 135 ° C. for 5 minutes.

  Further, both surfaces were buffed with a 240th sandpaper, and both surfaces were ground and smoothed by 15/100 mm.

Next, the water-soluble thermoplastic PVA as an island component was dissolved and removed from the sea-island type composite fiber in the three-dimensional entangled body by dip nip so as to have a hot water immersion time of 30 minutes in 95 ° C. hot water. . At this time, the tension applied to the raw material conveyed continuously was adjusted to 15 kg / cm by the load applied to the dancer roll. Then, by performing a drying treatment, an apparent density of 0.248 g / cm ³ and a thickness of 1.82 mm including a non-woven fabric of PBT hollow fibers with an average fineness of 2.66 dtex having 12 hollow portions in the cross section and polyurethane. The raw material of the liquid-absorbing sheet having a polymer elastic body ratio P0.277 of polymer elastic body / hollow fiber = 27.7 / 72.3 was obtained.

The resulting absorbent sheet has a hollow fiber weight per unit area (M) of 288 g / m ² and an apparent density (C) of the hollow fiber of 0.655 g / cm ^3. Since the fiber diameter E (cm) of the fiber was 1.63 × 10 ⁻³ ,
The total surface area S (m ² ) of the hollow fibers contained in the raw sheet of the liquid-absorbing sheet having a unit area (1 m ² ) is calculated from the above formula (1):
S (m ² ) = (4 × 288 (g / m ² ) × 10 ⁻⁴ ) / (0.655 (g / cm ³ ) × 1.63 × 10 ⁻³ (cm)) = 107.8 Calculated.

Further, since the basis weight G of the original fabric of the obtained liquid-absorbing sheet was 398 g / m ² , the polymer elastic body weight U contained in the original fabric of the unit area (1 m ² ) is:
^{U (g / m 2) =} 398 (g / m 2) was × 0.277 = 110.2g / ^{m 2.} As a result, the ratio U / S of the weight (g) of the polymer elastic body to the total surface area (m ² ) of the hollow fiber was 1.02 (g / m ² ).

  The above evaluation was performed using the raw material of the liquid-absorbing sheet thus obtained. The results are shown in Table 1.

[Example 2]
In the production of the raw material of the liquid absorbent sheet of Example 1, in the step of dissolving and removing the water-soluble thermoplastic PVA of the island component from the sea-island type composite fiber in the three-dimensional entangled body, the raw material is continuously conveyed. Instead of adjusting the tension to 15 kg / cm, a raw material of the liquid absorbent sheet was produced and evaluated in the same manner as in Example 1 except that the tension was adjusted to 0 kg / cm without applying a load to the dancer roll. The results are shown in Table 1.

[Example 3]
In the production of the raw material of the liquid absorbent sheet of Example 1, instead of Novaduran 5010 (melt viscosity [temperature 270 ° C., shear rate 1000 ⁻¹ ] 150 Pa / s) as PBT, Novaduran 5020 (same melt viscosity 250 Pa / s) In the step of changing the spinning speed to 23000 m / min and adjusting to about 3000 m / min, and further dissolving and removing the water-soluble thermoplastic PVA of the island component from the sea-island composite fiber in the three-dimensional entangled body, Instead of adjusting the tension applied to the continuously conveyed raw material to 15 kg / cm, the liquid absorbent sheet was the same as in Example 1 except that the tension was adjusted to 0 kg / cm without applying a load to the dancer roll. An original fabric was manufactured and evaluated. The results are shown in Table 1.

[Example 4]
In the production of the raw material of the liquid absorbent sheet of Example 1, instead of Novaduran 5010 (melt viscosity [temperature 270 ° C., shear rate 1000 ⁻¹ ] 150 Pa / s) as PBT, Novaduran 5020 (same melt viscosity 250 Pa / s) , Change to 60/40 instead of 50/50 mass ratio of sea component / island component, adjust spinning speed to 23000 m / min and adjust to about 3000 m / min. In the process of dissolving and removing the water-soluble thermoplastic PVA as an island component from the sea-island type composite fiber, instead of adjusting the tension applied to the continuously conveyed raw fabric to 15 kg / cm, without applying a load to the dancer roll The raw material of the liquid absorbent sheet was manufactured and evaluated in the same manner as in Example 1 except that the tension was adjusted to 0 kg / cm. The results are shown in Table 1.

[Example 5]
In the production of the original sheet of the liquid-absorbing sheet of Example 1, the spinning speed was changed to 2250 m / min and adjusted to about 3000 m / min, and from the island-island composite fiber in the three-dimensional entangled body, In the process of dissolving and removing the water-soluble thermoplastic PVA, the tension is adjusted to 0 kg / cm without applying a load to the dancer roll, instead of adjusting the tension applied to the continuously conveyed raw fabric to 15 kg / cm. Further, by adjusting the amount of impregnation of the polymer elastic body, the ratio (g / m ² ) of the weight (g) of the polymer elastic body to the total surface area (m ² ) of the hollow fiber is 0.00 instead of 1.00. Except having changed so that it might be set to 51, the raw material of the liquid absorption sheet was manufactured similarly to Example 1, and evaluated. The results are shown in Table 1.

[Comparative Example 1]
In the production of the original sheet of the liquid-absorbing sheet of Example 1, instead of Novaduran 5020 (same melt viscosity 150 Pa / s) as PBT, Novaduran 5020 (same melt viscosity 250 Pa / s) was used, and the mass of sea component / island component The fiber is changed to 60/40 instead of the ratio 50/50, the spinning speed is changed to 2250 m / min and adjusted to about 3000 m / min, and the impregnation amount of the polymer elastic body is adjusted to obtain hollow fibers. The ratio (g / m ² ) of the weight (g) of the polymer elastic body to the total surface area (m ² ) was changed to 1.16 instead of 1.00. The raw material of the liquid absorbing sheet was manufactured and evaluated. The results are shown in Table 1.

[Comparative Example 2]
In the production of the original sheet of the liquid-absorbing sheet of Example 1, Novaduran 5020 (same melt viscosity 250 Pa / s) was used as PBT instead of Novaduran 5010 (same melt viscosity 150 Pa / s), and the mass of sea component / island component The fiber is changed to 60/40 instead of the ratio 50/50, the spinning speed is changed to 2250 m / min and adjusted to about 3000 m / min, and the impregnation amount of the polymer elastic body is adjusted to obtain hollow fibers. The ratio (g / m ² ) of the weight (g) of the polymer elastic body to the total surface area (m ² ) was changed to 1.48 instead of 1.00. The raw material of the liquid absorbing sheet was manufactured and evaluated. The results are shown in Table 1.

From the results in Table 1, the water absorbent sheets of Examples 1 to 6 having a 20% strength of 20 kg / 2.5 cm or less had a high compression rate while maintaining a high water absorption rate. Therefore, according to such a water-absorbent sheet, when a liquid-absorbing roll formed into a disc-shaped sheet having a through-hole in the center and compressed by fixing a large number of the through-holes through the core material, the liquid-absorbing roll is configured. In addition, it can be seen that a liquid-absorbing roll is obtained in which the disk-like sheet is compressed and brought into close contact, and a gap is hardly formed. Moreover, the water absorbing sheets of Examples 1 to 4 and 6 in which the ratio (g / m ² ) of the weight (g) of the polymer elastic body to the total surface area (m ² ) of the hollow fiber is in the range of 0.65 to 1.4. All had less fluff loss. On the other hand, Comparative Examples 1 and 2 in which 20% strength exceeded 20 kg / 2.5 cm had a low compression rate.

  The liquid-absorbing sheet of the present invention is preferably used as a material for a liquid-absorbing roll for removing excess liquid adhering to the surface of an article or part or adhering liquid to the surface of an article or part.

DESCRIPTION OF SYMBOLS 1 Nonwoven fabric 1a Hollow fiber 2 Polymer elastic body 10 Liquid absorbing sheet 20 Liquid absorbing roll

Claims (8)

A non-woven fabric of hollow fibers of long fibers, and a polymer elastic body imparted to the voids of the non-woven fabric,
A liquid-absorbing sheet having a 20% strength of 20 kg / 2.5 cm or less. ^2. The liquid-absorbent sheet according to claim 1, wherein a ratio of a weight (g) of the polymer elastic body to a total surface area (m ² ) of the hollow fiber is 0.6 to 1.4 (g / m ² ).   The liquid-absorbing sheet according to claim 1, wherein the hollow fiber is a polyester fiber.   The liquid-absorbing sheet according to claim 1, wherein the polyester fiber is a polybutylene terephthalate fiber.   The liquid-absorbent sheet according to any one of claims 1 to 4, wherein the hollow fiber is a fiber produced by selectively removing island components from a composite-spun sea-island type composite fiber.   The liquid absorbent sheet according to any one of claims 1 to 5, wherein the polymer elastic body is a polyurethane derived from an aqueous polyurethane emulsion. The liquid-absorbing sheet according to any one of claims 1 to 6, which has an apparent density of 0.2 to 0.5 g / cm ³ . A liquid-absorbing roll for absorbing liquid adhering to the member to be processed or supplying liquid to the member to be processed, and penetrating the liquid-absorbing sheet according to any one of claims 1 to 7 in the center. A liquid-absorbing roll, which is formed by forming a disk-shaped sheet having holes, compressing and fixing a large number of through-holes through the core material.

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