JP2006334792A - Ink waste liquid absorber and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink waste liquid absorber whereby an excellent absorbability to a dye ink and a pigment ink is maintained at a high level, and to provide its manufacturing method. <P>SOLUTION: The ink waste liquid absorber has a surfactant and a binder impregnated in a soft polyurethane foam manufactured by using foaming materials including a polyol, an isocyanate and a foaming agent. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink waste liquid absorber that maintains a high level of excellent absorbency for dye inks and pigment inks, and a method for producing the same.

  In recent years, with the spread of personal computers, many types of printers have been provided. Many of these printers employ a laser system or an ink jet system. In particular, the ink jet system is widely used because it is less expensive than the laser system.

  Here, in an ink jet printer, excess ink is accumulated in the printer due to cleaning of the printer head or the like, but this may flow out and stain the vicinity of the printer head. For this reason, an ink absorbing material that absorbs excess ink is spread over the printer head.

  Such an ink absorbing material is required to absorb excess ink quickly and not to pollute the environment in the printer. Initially, pulp or fibrous non-woven fabric was used as the ink absorbing material, but there was concern about the problem of fibers scattered in the printer due to fuzz. In order to solve such a problem, the present applicant previously described in Japanese Patent Application Laid-Open No. 2001-105630 and Japanese Patent Application Laid-Open No. 2002-029066, since the polyurethane foam is used as a base material. In addition, an ink waste liquid absorber that is homogeneous and accurate and has a very high ink absorbability is proposed.

  However, the ink waste liquid absorber is required to have higher performance. One of the required characteristics is that the ink absorption performance is kept constant at a high level.

JP 2001-105630 A JP 2002-029066 A

  The present invention is an improvement of the above circumstances, and an object of the present invention is to provide an ink waste liquid absorber that maintains excellent absorbency for dye ink and pigment ink at a high level and a method for producing the same.

  As a result of intensive studies to achieve the above object, the present invention forms the inside of the flexible polyurethane foam (the surface of the skeleton forming the three-dimensional communication network structure of the flexible polyurethane foam) and / or the outside (the outer shape of the flexible polyurethane foam). When an ink absorber is formed by coating a surface active agent on the outer surface, the surface active agent may flow out along with the ink when absorbing / transmitting the falling ink. It has been found that a decrease in the amount of the surfactant present on the outer surface of the body can reduce the ink absorption rate at the time of contact with the ink, which in turn can reduce the absorption performance of the ink absorber. And it discovered that such a phenomenon could be eliminated by making a binder coexist in the said surfactant, and came to make this invention.

That is, the present invention provides the following ink waste liquid absorber and method for producing the same.
Claim 1:
An ink waste liquid absorber, wherein a flexible polyurethane foam produced using a foaming raw material containing a polyol, an isocyanate and a foaming agent is impregnated with a surfactant and a binder.
Claim 2:
The waste liquid absorber according to claim 1, wherein the flexible polyurethane foam is an uncompressed foam.
Claim 3:
The waste liquid absorber according to claim 1, wherein the flexible polyurethane foam is a compression foam.
Claim 4:
4. The ink waste liquid absorber according to claim 1, wherein the flexible polyurethane foam is a flexible polyurethane foam having an air permeability of 1.0 cc / cm ² / sec or more.
Claim 5:
The ink waste liquid absorber according to any one of claims 1 to 4, wherein the flexible polyurethane foam is a flexible polyurethane foam having no cell membrane.
Claim 6:
The ink waste liquid absorber according to any one of claims 1 to 5, wherein an impregnation amount of the binder is 1 to 500,000 g / m ³ .
Claim 7:
The ink waste liquid absorber according to any one of claims 1 to 6, wherein the binder is an acrylic resin and / or a polyurethane resin.
Claim 8:
A method for producing a waste liquid absorber according to any one of claims 1 to 7, wherein a flexible polyurethane foam is obtained using a foaming raw material containing polyol, isocyanate and foaming agent, and the surfactant and binder are dispersed or dissolved. A method for producing an ink waste liquid absorber, wherein the flexible polyurethane foam is immersed in a liquid, the solvent is dried, and a surfactant is attached to the flexible polyurethane foam together with a binder.
Claim 9:
A method for producing a waste liquid absorber according to any one of claims 1 to 7, wherein a flexible polyurethane foam is obtained using a foaming raw material containing polyol, isocyanate and foaming agent, and the surfactant and binder are dispersed or dissolved. A method for producing an ink waste liquid absorber, comprising spraying a liquid onto a flexible polyurethane foam, drying the solvent, and attaching the surfactant together with the binder to the flexible polyurethane foam.
Claim 10:
A method for producing a waste liquid absorber according to any one of claims 1 to 7, wherein a flexible polyurethane foam is obtained using a foaming raw material containing a polyol, an isocyanate and a foaming agent, and a surfactant is dispersed or dissolved therein. A liquid in which a binder is dispersed or dissolved is sprayed separately or simultaneously on a flexible polyurethane foam, and then the solvent is dried, so that a surfactant is attached to the flexible polyurethane foam together with the binder. Method.
Claim 11:
The method according to claim 8, 9 or 10, wherein the flexible polyurethane foam to which the surfactant is adhered is further compression molded.

  According to the present invention, there is provided an ink waste liquid absorber that achieves high ink absorbency that is uniform and accurate and that maintains its high performance. In addition, even if the shape of the set part in the printer is complicated, the ink absorber can be easily cut according to the shape and is made of polyurethane foam as a base material. In addition, there is no worry about the fluffing and falling of the fluff, and the printer function is not adversely affected.

The present invention will be described in more detail below.
The ink waste liquid absorber of the present invention is an ink waste liquid absorber obtained by impregnating a surfactant and a binder into a flexible polyurethane foam produced using a polyurethane foam raw material containing a polyol, an isocyanate and a foaming agent.

Examples of the polyol in the present invention include poly (oxyethylene-oxyalkylene) polyether polyols obtained by adding an alkylene oxide other than ethylene oxide and ethylene oxide to an active hydrogen-containing compound having two or more functional groups. Here, examples of the alkylene oxide component include propylene oxide, butylene oxide, styrene oxide and the like. These can be used alone or in combination of two or more.
Examples of the active hydrogen-containing compound used for producing the polyol include polyalcohols and polyamines. Examples of polyalcohols include ethylene glycol, propylene glycol, glycerin, trimethylolpropane, 1,2 , 6-hexanetriol, pentaerythritol, sorbitol, sucrose and the like.

  In addition, as the polyol, a hydrophilic organic acid metal salt and / or a polymer-containing polyol can be used as a part of the polyol, and organic acid potassium, magnesium, tin, copper, lithium, or silver can be used. Salts and the like are effective, and potassium salts and sodium salts are preferable. Such a polyol can be used by blending with a polyol used for production of a normal flexible polyurethane foam.

  Although it does not specifically limit as said isocyanate in this invention, For example, toluene diisocyanate, phenylene diisocyanate, diphenylmethane diisocyanate, 4,4'-diphenyl diisocyanate etc. are mentioned. Of these, toluene diisocyanate having a 2,4- / 2,6-isomer ratio of 80/20 to 65/35 is preferable from the viewpoint of economy, and is based on the total amount of polyol and other compounds having active hydrogen. The amount of organic isocyanate used, that is, the isocyanate index is usually in the range of 80 to 130, but is preferably in the range of 100 to 110.

  As the foaming agent in the present invention, for example, water, methylene chloride, a volatile liquid having a low boiling point, or the like is used.

In addition to the above-described blending components, the foaming raw material is further added with a catalyst, a foam stabilizer, a cross-linking material, a filler, an antistatic agent, a colorant, a flame retardant and the like according to the performance required for the foam. be able to.
Examples of such a catalyst include an organotin compound catalyst and an amine catalyst. Examples of organotin compound catalysts include stannous octoate, stannous oleate, dibutylditin laurate, dibutyltin di-2-ethylhexoate, and dibutyltin diacetate. On the other hand, as an amine catalyst, amine catalysts generally used, for example, triethylamine, triethylenediamine, N-ethylmorpholine, dimethylethanolamine, dimethylbenzylamine, 1,8-diazabicyclo (5.4.0) undecene- 7 and its phenol salt, formate of triethylenediamine and the like can be used as they are. These catalysts can be used alone or in admixture of two or more. As the amine-based catalyst, an amine-based catalyst usually used for foaming flexible polyurethane foam is used, but a reactive amine-based catalyst is preferably used for applications where elution is a problem. Although the usage-amount of a catalyst is not specifically limited and can be changed in a wide range, Usually, it is the range of 0.005-2 mass parts with respect to 100 mass parts of polyols.

  As the foam stabilizer, a silicone-based foam stabilizer or the like commonly used for foaming flexible polyurethane foams can be used. For applications where elution is a problem, it is preferable to use a reactive foam stabilizer. The amount of use is usually 0.1 to 3.0 parts by mass, preferably 0.5 to 2.0 parts by mass with respect to 100 parts by mass of the polyol.

As a method for producing a flexible polyurethane foam using the foaming raw material, a conventional method is adopted. As the obtained flexible polyurethane foam, the density is preferably 0.005 to 0.150 g / cm ³ , particularly preferably 0.01 to 0.05 g / cm ³ , and the number of cells is 40 to 150 pieces / 25 mm, or The number is preferably 50 to 150 pieces / 25 mm, particularly preferably 60 to 150 pieces / 25 mm. In this case, when the flexible polyurethane foam is compressed and used, the number of cells is preferably 20 to 300/25 mm, or 40 to 150/25 mm, particularly 40 to 100/25 mm.

Further, in the present invention, the flexible polyurethane foam can be used as it is (uncompressed foam) or compressed (compressed foam) without being compressed, but any one of them is a tertiary in which an internal communication space is formed. A flexible polyurethane foam having an original net-like skeleton structure and having the inside and the outside communicate with each other is preferable. The air permeability of the flexible polyurethane foam is usually 1.0 cc / cm ² / sec or more, preferably 5.0 to 300 cc / cm ² / sec, more preferably 10 to 300 cc / cm ² / sec, still more preferably 20 to 300 cc / cm ² / sec. If the air permeability is too low, the ink absorption performance may be inferior, and the object of the present invention may not be achieved. Here, the air permeability is a measured value according to JIS-K6400.

  The flexible polyurethane foam having the air permeability can be obtained by appropriately selecting the foam density, the number of cells, the cell diameter, the porosity, etc. In this case, the flexible polyurethane foam has no cell membrane ( It is effective to use a filmless foam. This flexible polyurethane foam without cell membrane is obtained by a method of removing the cell membrane after obtaining a flexible polyurethane foam having a cell membrane by a normal formulation, or a method of producing a flexible polyurethane foam by a formulation not producing a cell membrane. be able to.

  Further, as described above, the flexible polyurethane foam may be an uncompressed one or a compressed one, but the compression ratio can be 1 to 20 times. Here, the compression ratio of 1 is in an uncompressed state, and therefore the compressed foam may be a slightly compressed non-compressed foam, but usually 2 to 20 times, more preferably What was compressed 5-10 times, more preferably 8-10 times is used. In addition, although there is no limitation in the compression method, the hot press method is employ | adopted normally, The method of compressing to predetermined magnification using a hot plate of about 150-240 degreeC, and fixing to this compression magnification is employable. The hot press time is not particularly limited, but can be, for example, about 2 to 20 minutes.

  In addition, when the ink waste liquid absorber of the present invention is used as an ink absorbing material, for example, in contact with an ink conducting material, a plurality of layers having different air permeability are increased from the ink absorbing side, and the ink absorbing side is increased. It is preferable to use a laminate in which the ink holding capacity is increased as the distance from the head increases, that is, the ink absorption side has a high air permeability, and the air permeability is sequentially reduced. For example, the ink absorption side can be an uncompressed foam and the opposite side can be a compressed foam, or can be laminated so that the compression ratio increases sequentially from the ink absorption side.

  As a means for forming a plurality of layers as described above, a method of laminating two to six layers, particularly about three to five layers having different compression ratios and / or cell numbers is employed. Further, when the foam is thermally compressed, it may be compressed by applying a hot plate to only one side of the foam.

  Ink absorption performance can be further improved by slitting the outer surface of the ink waste liquid absorber on the ink absorption side. In this case, the slits can be provided in parallel with each other at intervals of 2 to 50 mm, particularly 5 to 10 mm, or in a grid pattern.

  The ink waste liquid absorber of the present invention is formed by impregnating the flexible polyurethane foam with a surfactant and a binder. By such impregnation and adhesion of the surfactant and the binder, not only the ink absorbability of the flexible polyurethane foam can be further improved, but also the improved ink absorption performance can be maintained at a high level. In other words, in an ink waste liquid absorber impregnated with a surfactant without using a binder, the surfactant may bleed out when a strong pressure such as grasping by hand is applied, or the ink is continuously absorbed. In some cases, however, the ink absorption performance may be reduced, so there was still room for improvement from the viewpoint of workability and performance stability, but in the present invention, by coexisting a binder with a surfactant. Such a problem has been solved.

  Examples of the surfactant include anionic surfactants such as succinate, carboxylate, phosphate, sulfonate, and ethylene oxide; cationic surfactants such as alkylamine salts and quaternary ammonium salts; Nonionic surfactants such as polyethylene glycol alkyl ethers, sorbitan fatty acid esters, alkyl allyl ethers, alkyl ethers, alkyl esters, alkylamines, phenyl ethers, alkylalkanolamides; amino acids, alkylbetaines, amine oxides, alkylimidazoliniums, etc. Any of amphoteric surfactants; silicone-based surfactants such as polysiloxane; fluorine-based surfactants; and the like can be used. These may be used alone or in combination of two or more. In the present invention, polymeric surfactants and reactive surfactants can also be suitably used.

  Among these, a sodium succinate modified product is particularly preferably used in terms of effects. In this case, as the modified sodium succinate, succinic acid dialkyl ester sulfonic acid soda represented by the following formula is preferably used.

（但し、Ｒはアルキル基又はアラルキル基であり、炭素数１〜１８のものが挙げられる。）

(However, R is an alkyl group or an aralkyl group, and a C1-C18 thing is mentioned.)

  Specific examples of the ester include di-n-amyl, di-n-hexyl, di-n-heptyl, di-n-octyl, di-n-nonyl, monoethyl monododecyl, monobutyl monododecyl, and mono-2. -Ethylhexyl-mono-1-methylbenzyl, mono-2-ethylhexyl-mono-1-methyl-4-ethylhexyl, di-1-methylbutyl, di-2-methylbutyl, di-isoamyl, di-1,3-dimethylbutyl , Di-1-methylamyl, di-dimethylamyl, di-1-isopropylisobutyl, di-1-propylbutyl, di-1-methylhexyl, di-2-ethylhexyl, di-1-methylheptyl, di-1- Butyl amyl, di-1-isobutyl-3-methylbutyl, di-1-methyl-4-ethylhexyl, di-1-methyl-4-ethyloctyl, etc. And the like.

Such surfactants are preferably water-soluble if possible because it is only necessary to dry the water after impregnating the foam. The impregnation amount of the surfactant varies depending on the required performance, but is usually 1 to 500,000 g / m ³ , preferably 50 to 100,000 g / m ³ , more preferably 5,000 to 50,000 g. / M ³ .

  On the other hand, as the binder, for example, any of oil-based, oil-dispersible, water-soluble, water-dispersible, and amphiphilic binders can be used. Among these, those which can be dissolved or dispersed in a solvent such as water and form a film by removing the solvent are suitable. In this respect, organic polymer materials such as resins and elastomers are suitable. These may be either thermoplastic or thermosetting.

  Examples of such resins include urethane resins, acrylic resins, urea resins, guanamine resins, melamine resins, phenol resins, formaldehyde resins, epoxy resins, ester resins, vinyl chloride resins, and various alkyl resins (polyethylene, polypropylene, polybutene, etc.) Allyl resin, styrene resin, nylon resin, ABS resin, carbonate resin, acetal resin, vinyl resin, phthalate resin, amide resin, imide resin, furan resin, methylpentene resin, phenylene sulfide resin, cellulose resin, rayon, silicon Examples thereof include resins, fluorine resins, and copolymers of two or more of these. Examples of the elastomer include rubber (latex) such as butyl, EPDM, butadiene, and isoprene. These may be used alone or in combination of two or more. In the combined use, a solution or dispersion of each component may be prepared in advance and then mixed.

The binder may be water-soluble if possible, because it is only necessary to dry the water after impregnating the foam. The amount of binder impregnation varies depending on the required performance, but is usually 1 to 500,000 g / m ³ , preferably 50 to 100,000 g / m ³ , more preferably 5,000 to 50,000 g / m. ³ .

  In addition, as a specific combination of the surfactant and the binder, any combination that does not significantly impair the surface tension reduction function of the ink by the surfactant and does not hinder the uniform coating of the binder. Although it can be used and is not particularly limited, as a binder, for example, an acrylic resin aqueous dispersion (for example, manufactured by AE815, JSR), an acrylic / styrene copolymer resin aqueous dispersion (for example, TOCRYL W-461; Toyo) Ink Manufacture Co., Ltd.), urethane resin aqueous dispersion (for example, Takelac WS-5000, manufactured by Mitsui Takeda Chemical Co., Ltd.) and a surfactant such as di- (normal octyl) sulfosuccinate sodium salt (For example, Ripar 870P, anionic surfactant, manufactured by Lion Corporation), polyoxyethylene 1 type or 2 types or more of alkyl ethers (for example, Leocol TD-150, nonionic surfactant, manufactured by Lion), lauryltrimethylammonium chloride (for example, Cotamine 24P, cationic surfactant, manufactured by Kao) Combinations are listed as suitable combinations.

  The ratio of the surfactant and the binder impregnated into the foam is usually 1/10 to 10/1 as (surfactant impregnated amount) / (binder impregnated amount) (mass ratio) value. Preferably it is 1/7 to 7/1, more preferably 1/3 to 3/1, still more preferably 1/2 to 2/1. If the amount of the binder impregnated is too small, the binder may not sufficiently obtain the function of fixing the surfactant. On the other hand, if the amount of the surfactant impregnated is too small, the ink absorption and transmission performance is sufficient. May not be obtained.

Examples of the method for repairing the impregnation of the surfactant and the binder into the flexible polyurethane foam include the following methods.
(I) A method in which a flexible polyurethane foam is immersed in a liquid in which a surfactant and a binder are dispersed or dissolved, and after the excess liquid is squeezed out, the solvent is dried.
(Ii) A method of spraying an appropriate amount of a liquid in which a surfactant and a binder are dispersed or dissolved onto a flexible polyurethane foam and then drying the solvent.
(Iii) A method in which a liquid in which a surfactant is dispersed or dissolved and a liquid in which a binder is dispersed or dissolved are separately or simultaneously applied to a flexible polyurethane foam in an appropriate amount, and then the solvent is dried.

  In addition, after forming the flexible polyurethane foam to which the surfactant is adhered as described above, it is also preferable to perform compression molding.

  The ink waste liquid absorber of the present invention is particularly suitable as an ink conducting material or an ink absorbing material corresponding to a printer head, and an ink absorber to be brought into contact with the ink conducting material.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example. In addition, a part shows a mass part by the following example.

[Production Example 1]
Manufacture of flexible polyurethane foam A Polyol (V3030, manufactured by Dow Co., Ltd.), 100 parts, TDI80 (manufactured by Nippon Polyurethane Co., Ltd.), 50 parts, water, 4 parts, amine catalyst (DABCO-33LV, manufactured by Mitsui Air Products), 0 Using a foaming raw material containing 3 parts, tin catalyst (Stanas octoate, manufactured by Nitto Kasei Co., Ltd.), 0.3 part, silicone foam stabilizer (L-520, manufactured by Nihon Unica), 1 part, one shot The flexible polyurethane foam A was obtained by the method. The density of the obtained foam (JIS-K6400) was 0.020 g / cm ³ and the number of cells was 55 (per inch). The air permeability was 18 cc / cm ² / sec.

[Production Example 2]
Production of flexible polyurethane foam B The flexible polyurethane foam A was cut into 50 mm × 100 mm × 100 mm and heat-compressed at a compression degree of 5 times (200 ° C., 300 seconds) to obtain a flexible polyurethane foam B. The dimensions of the obtained foam were 10 mm × 100 mm × 100 mm, the density (JIS-K6400) was 0.100 g / cm ³ , and the number of cells was 275 (per inch).

[Examples 1 to 10, Comparative Examples 1 to 5]
A flexible polyurethane foam A or B having dimensions of 10 mm × 100 mm × 100 mm was dipped in a liquid in which the following solutions were mixed, pulled up, and the solvent was dried in an oven at 130 ° C. for 5 minutes to obtain an ink waste liquid absorber. . The ink absorption performance of the obtained ink waste liquid absorber was evaluated. The results are also shown in Table 1.

Surfactant 1
Sodium di- (normal octyl) sulfosuccinate, Lipar 870P (manufactured by Lion Corporation) was dissolved in water to obtain a solution having a concentration of 30% by mass.
Surfactant 2
Polyoxyethylene alkyl ether, Leocol TD-150 (manufactured by Lion Corporation) was dissolved in water to obtain a solution having a concentration of 30% by mass.
Binder 1
Takerak WS-5000 (resin concentration 30% by mass, manufactured by Mitsui Takeda Chemical Co., Ltd.) was used.
Binder 2
Water was added to TOCRYL W-461 (resin concentration 55% by mass, manufactured by Toyo Ink Manufacturing Co., Ltd.) to obtain a resin concentration of 30% by mass.

Surfactant or binder impregnation amount The total amount of the surfactant and binder impregnated was calculated by subtracting the mass of the flexible polyurethane foam from the mass of the obtained ink waste liquid absorber. The impregnation amount of each of the surfactant and the binder was calculated on the assumption that the impregnation amount ratio was equal to the blending ratio of each component in each liquid used.
Absorption performance (initial, after ink absorption)
Set the tip of the syringe needle to the center of the top surface of the test piece (thickness 10 mm x 100 mm x 100 mm) placed horizontally at a height of 5 cm from the top of the test piece, and apply 1 cc of ink for about 4 seconds. After the dropping, the time (seconds) until the ink was absorbed from the surface of the test piece was measured.
(Initial) Absorption performance in the state of manufacturing an ink waste liquid absorber.
(After ink absorption) The addition of 0.05 cc of black pigment ink onto the test piece was repeated 50 times at an interval of 1 time / second, and the absorption performance was measured after another 3 minutes. In the sample with low absorption performance, ink remained on the surface even after 3 minutes.
Absorption performance (after water immersion)
After immersing the test piece in 500 ml of water at room temperature for 24 hours, the water was squeezed and dried in an oven at 130 ° C. for 3 minutes. Set the tip of the syringe needle to the center of the top surface of the test piece (thickness 10 mm x 100 mm x 100 mm) placed horizontally at a height of 5 cm from the top of the test piece, and apply 1 cc of water for about 4 seconds. After the dripping was completed, the time (seconds) until water was absorbed from the surface of the test piece was measured.

Claims (11)

  An ink waste liquid absorber, wherein a flexible polyurethane foam produced using a foaming raw material containing a polyol, an isocyanate and a foaming agent is impregnated with a surfactant and a binder.   The waste liquid absorber according to claim 1, wherein the flexible polyurethane foam is an uncompressed foam.   The waste liquid absorber according to claim 1, wherein the flexible polyurethane foam is a compression foam. 4. The ink waste liquid absorber according to claim 1, wherein the flexible polyurethane foam is a flexible polyurethane foam having an air permeability of 1.0 cc / cm ² / sec or more.   The ink waste liquid absorber according to any one of claims 1 to 4, wherein the flexible polyurethane foam is a flexible polyurethane foam having no cell membrane. The ink waste liquid absorber according to any one of claims 1 to 5, wherein an impregnation amount of the binder is 1 to 500,000 g / m ³ .   The ink waste liquid absorber according to any one of claims 1 to 6, wherein the binder is an acrylic resin and / or a polyurethane resin.   A method for producing a waste liquid absorber according to any one of claims 1 to 7, wherein a flexible polyurethane foam is obtained using a foaming raw material containing polyol, isocyanate and foaming agent, and the surfactant and binder are dispersed or dissolved. A method for producing an ink waste liquid absorber, wherein the flexible polyurethane foam is immersed in a liquid, the solvent is dried, and a surfactant is attached to the flexible polyurethane foam together with a binder.   A method for producing a waste liquid absorber according to any one of claims 1 to 7, wherein a flexible polyurethane foam is obtained using a foaming raw material containing polyol, isocyanate and foaming agent, and the surfactant and binder are dispersed or dissolved. A method for producing an ink waste liquid absorber, comprising spraying a liquid onto a flexible polyurethane foam, drying the solvent, and attaching the surfactant together with the binder to the flexible polyurethane foam.   A method for producing a waste liquid absorber according to any one of claims 1 to 7, wherein a flexible polyurethane foam is obtained using a foaming raw material containing a polyol, an isocyanate and a foaming agent, and a surfactant is dispersed or dissolved therein. A liquid in which a binder is dispersed or dissolved is sprayed separately or simultaneously on a flexible polyurethane foam, and then the solvent is dried, so that a surfactant is attached to the flexible polyurethane foam together with the binder. Method. The method according to claim 8, 9 or 10, wherein the flexible polyurethane foam to which the surfactant is adhered is further compression molded.