Liquid absorber and liquid absorption device

Abstract

To provide a liquid absorber which can more quickly diffuse a supplied liquid, and is excellent in absorption characteristics.SOLUTION: A liquid absorber has an absorption layer which has a water-absorbing resin and has liquid absorption property, and a base material layer which is stacked on at least one surface side of the absorption layer and has liquid penetration property, wherein the base material layer has a first layer containing cellulose, and a second layer which is positioned on a side opposite to the absorption layer of the first layer and has a basis weight different from that of the first layer, and when the basis weight of the first layer is represented by A1 (g / cm2) and the basis weight of the second layer is represented by A2 (g / cm2), A2<A1 is satisfied.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a liquid absorbent and a liquid absorber. [Background technology]

[0002] For example, in an inkjet printer, waste ink is generated during a head cleaning operation performed to prevent a decline in print quality due to clogging of the ink, and during an ink refill operation after replacing an ink cartridge. In addition, ink may leak from unintended places in the inkjet printer. Ink absorbers that absorb such ink are known. For example, Patent Document 1 discloses an ink absorber that is stored in a container and is made of felt containing fibers. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-65112 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the ink absorbent described in Patent Document 1 has insufficient ink absorption characteristics, particularly ink diffusibility. Therefore, depending on the ink dropping conditions, the ink dropped on the ink absorbent may not spread completely, and the ink may not spread completely. As a result, the ink absorption capacity of the ink absorbent is reduced. [Means for solving the problem]

[0005] The liquid absorbent of the present invention comprises an absorbent layer having a water-absorbent resin and liquid absorbency; A liquid-permeable base layer is laminated on at least one surface side of the absorbent layer, The base material layer has a first layer containing cellulose and a second layer located on the side opposite to the absorption layer of the first layer and having a basis weight different from that of the first layer. When the basis weight of the first layer is A1 (g / cm 2 ), and the basis weight of the second layer is A2 (g / cm 2 ), A2 < A1 is satisfied.

[0006] The liquid absorber of the present invention includes the liquid absorbent of the present invention and a container that houses the liquid absorbent and has a liquid supply section to which liquid is supplied.

Brief Description of the Drawings

[0007] [Figure 1] FIG. 1 is a cross-sectional side view of a liquid absorbent and a liquid absorber according to an embodiment of the present invention. [Diagram 2] FIG. 2 is an enlarged cross-sectional view of the liquid absorbent shown in FIG. 1. [Diagram 3] FIG. 3 is a plan view of the liquid absorbent shown in FIG. 1. [Figure 4] FIG. 4 is a cross-sectional side view for explaining a method of manufacturing the liquid absorbent shown in FIG. 1. [Diagram 5] FIG. 5 is a cross-sectional side view for explaining a method of manufacturing the liquid absorbent shown in FIG. 1. [Figure 6] FIG. 6 is a cross-sectional side view for explaining a method of manufacturing the liquid absorbent shown in FIG. 1. [Figure 7] FIG. 7 is a cross-sectional side view for explaining a method of manufacturing the liquid absorbent shown in FIG. 1.

Embodiments for Carrying Out the Invention

[0008] Hereinafter, the liquid absorbent and the liquid absorber of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

[0009] <First Embodiment> FIG. 1 is a cross-sectional side view of a liquid absorber and a liquid absorber according to an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view of the liquid absorber shown in FIG. 1. FIG. 3 is a plan view of the liquid absorber shown in FIG. 1. FIG. 4 is a cross-sectional side view for explaining a method for manufacturing the liquid absorber shown in FIG. 1. FIG. 5 is a cross-sectional side view for explaining a method for manufacturing the liquid absorber shown in FIG. 1. FIG. 6 is a cross-sectional side view for explaining a method for manufacturing the liquid absorber shown in FIG. 1. FIG. 7 is a cross-sectional side view for explaining a method for manufacturing the liquid absorber shown in FIG. 1.

[0010] In the following, for convenience of explanation, the upper side in Figures 1, 2, 4, 5, 6 and 7 will be referred to as "top" or "upper", and the lower side will be referred to as "bottom" or "lower".

[0011] As shown in FIG. 1, the liquid absorber 10 includes a liquid absorber 1 and a container 6 that stores the liquid absorber 1. The container 6 has an opening 60 that opens upward. In this embodiment, the container 6 is a tray. The container 6 is made of a hard material such as resin, glass, ceramics, or a metal material, and is liquid impermeable. The opening 60 functions as a liquid supply section that supplies a liquid such as ink 100 to the liquid absorber 1. The liquid supplied through the opening 60 is absorbed and held by the liquid absorber 1. Such a liquid absorber 10 is installed in, for example, a printing device and used to collect waste ink, i.e., ink 100 to be discarded. The liquid absorber 10 can also be used to collect waste liquid other than waste ink.

[0012] Examples of the liquid absorbed by the liquid absorber 1 include water, ink, body fluids, etc. Examples of the ink include water-based ink in which a coloring material is dissolved in a water-based solvent, as well as solvent-based ink in which a binder is dissolved in a solvent, UV-curable ink in which a binder is dissolved in a liquid monomer that is cured by UV irradiation, and latex ink in which a binder is dispersed in a dispersion medium. In the following, ink 100 will be described as a representative example of the liquid absorbed by the liquid absorber 1.

[0013] As shown in Fig. 1, the liquid absorber 1 has an absorbent layer 3 having liquid absorbency, and a base material layer 2 having liquid permeability, laminated on both sides of the absorbent layer 3. Ink 100 supplied to the upper base material layer 2 through an opening 60 permeates the base material layer 2, diffuses in the surface direction and thickness direction of the base material layer 2, and further transfers to the absorbent layer 3 adjacent to the inner side of the base material layer 2, where it is absorbed and held by the absorbent layer 3. The liquid absorber 1 has an overall shape of a sheet. However, the liquid absorber 1 is not limited to this configuration, and may have other shapes, such as a block shape.

[0014] The sheet-like liquid absorber 1 has a flat plate shape in the illustrated configuration, but may be entirely or partially curved or bent, unlike the illustrated configuration.

[0015] The configurations of the absorbent layer 3 and the base layer 2 will be described below. (Absorption layer 3) The absorbent layer 3 is mainly composed of a water-absorbing resin 30. The water-absorbing resin 30 is a resin that has water absorption properties and swells with water absorption. The water-absorbing resin 30 is not particularly limited, but examples thereof include carboxymethyl cellulose, polyacrylic acid, polyacrylamide, starch-acrylic acid graft copolymer, hydrolyzate of starch-acrylonitrile graft copolymer, vinyl acetate-acrylic acid ester copolymer, copolymer of isobutylene and maleic acid, hydrolyzate of acrylonitrile copolymer or acrylamide copolymer, polyethylene oxide, polysulfonic acid compounds, polyglutamic acid, salts (neutralized products), crosslinked bodies, etc. Here, water absorption refers to a function of having hydrophilicity and retaining moisture. Many water-absorbing resins 30 gel when they absorb water.

[0016] Among them, a resin having a functional group on the side chain is preferable as the water-absorbent resin 30. Examples of the functional group include an acid group, a hydroxyl group, an epoxy group, and an amino group.

[0017] In particular, the water-absorbent resin 30 is preferably a resin having an acid group on the side chain, and more preferably a resin having a carboxyl group on the side chain.

[0018] Examples of the carboxyl group-containing unit constituting the side chain include those derived from monomers such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, crotonic acid, fumaric acid, sorbic acid, cinnamic acid, and anhydrides and salts thereof.

[0019] When the water absorbent resin 30 has acid groups in its side chains, the ratio of the acid groups neutralized to form salts among the acid groups contained in the water absorbent resin 30 is preferably 30 mol % to 100 mol %, more preferably 50 mol % to 95 mol %, and even more preferably 60 mol % to 90 mol %. This allows the water absorbent resin 30 to have better absorbency of the ink 100.

[0020] The type of neutralization salt is not particularly limited, and examples thereof include alkali metal salts such as sodium salts, potassium salts, and lithium salts, and salts of nitrogen-containing basic substances such as ammonia, among which sodium salts are preferred. This allows the absorbency of the ink 100 by the water absorbent resin 30 to be more excellent.

[0021] The water-absorbent resin 30 having acid groups on the side chains is preferable because electrostatic repulsion occurs between the acid groups when absorbing ink, which increases the absorption speed. In addition, if the acid groups are neutralized, the ink 100 is easily absorbed into the water-absorbent resin 30 due to osmotic pressure.

[0022] The water-absorbent resin 30 may have a constituent unit that does not contain an acid group in the side chain. Examples of such a constituent unit include a hydrophilic constituent unit, a hydrophobic constituent unit, and a constituent unit that serves as a polymerizable cross-linking agent.

[0023] Examples of the hydrophilic constituent units include constituent units derived from nonionic compounds such as acrylamide, methacrylamide, N-ethyl(meth)acrylamide, Nn-propyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, methoxypolyethylene glycol(meth)acrylate, polyethylene glycol mono(meth)acrylate, N-vinylpyrrolidone, N-acryloylpiperidine, and N-acryloylpyrrolidine.

[0024] Examples of the hydrophobic structural unit include structural units derived from compounds such as (meth)acrylonitrile, styrene, vinyl chloride, butadiene, isobutene, ethylene, propylene, stearyl (meth)acrylate, and lauryl (meth)acrylate.

[0025] Examples of the structural unit that serves as the polymerizable crosslinking agent include structural units derived from diethylene glycol diacrylate, N,N-methylenebisacrylamide, polyethylene glycol diacrylate, polypropylene glycol diacrylate, trimethylolpropane diallyl ether, trimethylolpropane triacrylate, allyl glycidyl ether, pentaerythritol triallyl ether, pentaerythritol diacrylate monostearate, bisphenol diacrylate, isocyanuric acid diacrylate, tetraallyloxyethane, and diallyloxyacetate.

[0026] The water-absorbent resin 30 preferably contains a polyacrylate copolymer or a cross-linked polyacrylic acid polymer, which has the advantages of improving the liquid absorption performance and reducing the manufacturing cost, for example.

[0027] The crosslinked polyacrylic acid polymer is preferably one in which the proportion of structural units having a carboxyl group in all structural units constituting the molecular chain is 50 mol % or more, more preferably 80 mol % or more, and even more preferably 90 mol % or more.

[0028] If the proportion of structural units containing a carboxyl group is too low, this may be disadvantageous in achieving a sufficiently excellent ink absorbing performance.

[0029] The carboxyl groups in the crosslinked polyacrylic acid polymer are preferably partly neutralized (partially neutralized) to form a salt.

[0030] The proportion of neutralized carboxyl groups in the total carboxyl groups in the crosslinked polyacrylic acid polymer is preferably 30 mol % or more and 99 mol % or less, more preferably 50 mol % or more and 99 mol % or less, and even more preferably 70 mol % or more and 99 mol % or less.

[0031] The water-absorbent resin 30 may have a structure crosslinked with a crosslinking agent other than the above-mentioned polymerizable crosslinking agent.

[0032] When the water-absorbent resin 30 is a resin having an acid group, for example, a compound having a plurality of functional groups that react with the acid group can be preferably used as the crosslinking agent.

[0033] When the water-absorbing resin 30 is a resin having a functional group that reacts with an acid group, a compound having a plurality of functional groups that react with an acid group in the molecule can be suitably used as the crosslinking agent.

[0034] Examples of compounds (crosslinking agents) having a plurality of functional groups that react with acid groups include glycidyl ether compounds such as ethylene glycol diglycidyl ether, trimethylolpropane triglycidyl ether, (poly)glycerin polyglycidyl ether, diglycerin polyglycidyl ether, and propylene glycol diglycidyl ether; polyhydric alcohols such as (poly)glycerin, (poly)ethylene glycol, propylene glycol, 1,3-propanediol, polyoxyethylene glycol, triethylene glycol, tetraethylene glycol, diethanolamine, and triethanolamine; and polyvalent amines such as ethylenediamine, diethylenediamine, polyethyleneimine, and hexamethylenediamine. Polyvalent ions such as zinc, calcium, magnesium, and aluminum can also be used preferably because they react with the acid groups of the water absorbent resin 30 to function as crosslinking agents.

[0035] The water-absorbent resin 30 may have any shape, such as, for example, a scale-like, needle-like, fibrous, or particulate shape, but it is preferable that the majority of the water-absorbent resin 30 is particulate. When the water-absorbent resin 30 is particulate, the permeability of the ink 100 can be easily ensured. The average particle size of the particles is preferably 10 μm or more and 1000 μmm or less, more preferably 50 μm or more and 800 μm or less, and even more preferably 100 μm or more and 600 μm or less.

[0036] The absorbent layer 3 may contain components (other components) other than the water-absorbent resin 30. Examples of such components include surfactants, lubricants, antifoaming agents, fillers, ion-exchange resins, activated carbon, zeolite, antiblocking agents, ultraviolet absorbers, colorants such as pigments and dyes, flame retardants, and flowability improvers.

[0037] Such a water-absorbent resin 30 may or may not be supported on the base layer 2, particularly on the first layer 21 described below. When the water-absorbent resin 30 is supported on the base layer 2, the position of the water-absorbent resin 30 can be regulated to some extent, and it is possible to prevent the water-absorbent resin 30 from being unevenly distributed in the absorbent layer 3. Therefore, the liquid absorbent 1 can exhibit excellent absorption properties evenly.

[0038] The method of supporting the water-absorbent resin 30 on the base layer 2 is not particularly limited, and examples thereof include a method of bonding the water-absorbent resin 30 to the base layer 2 using an adhesive, a method of adding moisture to the water-absorbent resin 30 to make it sticky, and a method of adhering the water-absorbent resin 30 by this sticky property. When an adhesive is used, the adhesive is not particularly limited, but a water-soluble adhesive is preferable. In this way, when the ink 100 is water-based, the water-soluble adhesive dissolves when the ink 100 comes into contact with the adhesive, and therefore it is possible to prevent the penetration of the ink 100 into the water-absorbent resin 30 from being hindered.

[0039] When the volume of the water-absorbing resin 30 in a dry state, i.e., before absorbing the ink 100, is V1 and the volume after absorbing the maximum amount of ink 100 is V2, V2 / V1 is preferably 2 or more and 1000 or less, and more preferably 5 or more and 250 or less. This allows a sufficient amount of ink 100 to be absorbed.

[0040] (Base material layer 2) 2, the base material layer 2 is laminated on each of the upper surface 31, which is one surface side, of the absorbent layer 3, and the lower surface 32, which is the other surface side. That is, the liquid absorber 1 is configured such that the absorbent layer 3 is inserted between two base material layers 2. In this embodiment, since both base material layers 2 have the same configuration, the base material layer 2 on the upper surface 31 side will be representatively described below.

[0041] The base layer 2 has a first layer 21 and a second layer 22. In this embodiment, the planar shape of the first layer 21 and the second layer 22, i.e., the shape shown in Fig. 3, is substantially square, but is not limited to this configuration and may be any shape, such as a rectangle such as a rectangle, a triangle, a circle, an ellipse, a semicircle, a sector, a ring, or a polygon with 5 or more sides.

[0042] The first layer 21 and the second layer 22 may be bonded to each other at the boundary between them, may be in contact with each other, or may be spaced apart at a predetermined distance. In this embodiment, the first layer 21 and the second layer 22 are bonded to each other with a slight bonding force.

[0043] 2, the first layer 21 is located on the absorbent layer 3 side and faces the absorbent layer 3. The first layer 21 and the absorbent layer 3 may be bonded to each other at the boundary between them, may be in contact with each other, or may be spaced apart at a predetermined distance. In this embodiment, the first layer 21 is in contact with the absorbent layer 3.

[0044] The first layer 21 is a paper substrate composed primarily of cellulose fibers. Since cellulose is a material having suitable hydrophilicity, when the ink 100 is applied to the first layer 21, the ink 100 can be efficiently absorbed and the ink can be quickly released from a state of particularly high fluidity, for example, a state of viscosity of 10 mPa·s or less. Furthermore, the ink 100 once absorbed can be efficiently sent to the water-absorbent resin 30. As a result, the ink 100 absorption characteristics of the liquid absorber 1 as a whole can be made particularly excellent. Furthermore, cellulose fiber is a renewable natural material, and is inexpensive and easily available among various fibers, and is therefore advantageous from the viewpoints of reducing the production cost of the liquid absorber 1, stable production, reducing the environmental load, and the like.

[0045] In this specification, the cellulose fiber may be any fiber that contains cellulose as a compound as a main component, and may contain hemicellulose and lignin in addition to cellulose.

[0046] The average length of the cellulose fibers constituting the first layer 21 is not particularly limited, but is preferably 0.1 mm or more and 7 mm or less, more preferably 0.13 mm or more and 5 mm or less, and even more preferably 0.15 mm or more and 3 mm or less.

[0047] The average width (diameter) of the cellulose fibers constituting the first layer 21 is not particularly limited, but is preferably 0.05 mm or more and 2 mm or less, and more preferably 0.1 mm or more and 1 mm or less.

[0048] The average aspect ratio of the cellulose fibers constituting the first layer 21, ie, the ratio of the average length to the average width, is not particularly limited, but is preferably 10 or more and 1,000 or less, and more preferably 15 or more and 500 or less.

[0049] By setting the numerical range as described above, it is possible to obtain an appropriate diffusibility of the ink 100 in the first layer 21. Furthermore, the first layer 21 has an excellent carrying ability of the water-absorbent resin 30, and can efficiently transfer the ink 100 to the water-absorbent resin 30. Therefore, it is possible to further improve the ink 100 absorption characteristics of the liquid absorbent 1 as a whole.

[0050] 2, the second layer 22 is located on the opposite side of the first layer 21 to the absorbent layer 3. In other words, the second layer 22 is located on the surface of the liquid absorbent 1. The second layer 22 is a portion to which the ink 100 is supplied, and has the function of quickly penetrating and diffusing the ink 100 after absorbing it, in particular the function of diffusing in the plane direction of the second layer 22.

[0051] The second layer 22 includes fibers. Examples of the fibers of the second layer 22 include synthetic resin fibers such as polyester fibers and polyamide fibers, natural resin fibers such as cellulose fibers, keratin fibers, and fibroin fibers, and chemically modified fibers thereof, which may be used alone or in appropriate mixtures. In this embodiment, the second layer 22 is a nonwoven fabric made of the fibers.

[0052] The average length of the fibers constituting the second layer 22 is not particularly limited, but is preferably 0.05 mm or more and 6 mm or less, more preferably 0.06 mm or more and 4 mm or less, and even more preferably 1.00 mm or more and 2 mm or less.

[0053] The average width (diameter) of the fibers constituting the second layer 22 is not particularly limited, but is preferably 0.04 mm or more and 1.8 mm or less, and more preferably 0.08 mm or more and 0.9 mm or less.

[0054] The average aspect ratio (ratio of average length to average width) of the fibers constituting the second layer 22 is not particularly limited, but is preferably 10 or more and 1,000 or less, and more preferably 15 or more and 500 or less.

[0055] By setting the numerical range as described above, good diffusibility of the ink 100 can be obtained in the second layer 22. Furthermore, the second layer 22 can efficiently transfer the ink 100 to the water-absorbent resin 30. Therefore, the ink 100 absorption characteristics of the liquid absorbent 1 as a whole can be improved.

[0056] In addition, the second layer 22 is a nonwoven fabric, which can enhance the diffusibility of the ink 100 in the surface direction of the second layer 22, and also eliminates unevenness in the diffusibility depending on the diffusive direction.

[0057] However, the second layer 22 is not limited to a nonwoven fabric, and may be composed of, for example, a woven fabric or a paper base material similar to the first layer 21. The second layer 22 may also be an appropriate combination of a woven fabric, a nonwoven fabric, and a paper base material.

[0058] The second layer 22 is preferably hydrophilic, which further improves the diffusibility of the ink 100. The second layer 22 being hydrophilic includes any of the following cases: the fibers constituting the second layer 22 are themselves hydrophilic, the fibers constituting the second layer 22 have been subjected to a hydrophilization treatment, and the surface of the second layer 22 has been subjected to a hydrophilization treatment.

[0059] Examples of the hydrophilization treatment include chemical treatment such as addition of a surfactant, and physical treatment such as plasma treatment.

[0060] The first layer 21 and the second layer 22 may be made of the same material or different materials. In particular, the fibers contained in the first layer 21 and the fibers contained in the second layer 22 may all be the same material, some of the fibers may be the same material, or all may be different materials.

[0061] In addition to the above-mentioned fibers, the first layer 21 and the second layer 22 may contain a binder that binds the fibers together. This can sufficiently increase the strength of the first layer 21 and the second layer 22, and prevent breakage of unintended parts.

[0062] The binder is not particularly limited, and examples of the binder that can be used include thermoplastic resins, thermosetting resins, starch, dextrin, glycogen, amylose, hyaluronic acid, kudzu, konjac, potato starch, etherified starch, esterified starch, natural gum paste (etherified tamarind gum, etherified locust bean gum, etherified guar gum, acacia arabic gum), fiber-derived paste (etherified carboxymethylcellulose, hydroxyethylcellulose), seaweed (sodium alginate, agar), animal protein (collagen, gelatin, hydrolyzed collagen, sericin), etc., but it is preferable to use a thermoplastic resin.

[0063] Examples of the thermoplastic resin include, for example, AS resin, ABS resin, polyolefins such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer (EVA), modified polyolefins, acrylic resins such as polymethyl methacrylate, polyvinyl chloride, polystyrene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides (nylons) such as nylon 6, nylon 46, nylon 66, nylon 610, nylon 612, nylon 11, nylon 12, nylon 6-12, nylon 6-66, polyphenylene ether, polyacetal, polyether, polyphenylene oxide, polyether ether ketone, polycarbonate, polyphenylene sulfide, thermoplastic polyimide, polyetherimide, liquid crystal polymers such as aromatic polyester, and various thermoplastic elastomers such as styrene-based, polyolefin-based, polyvinyl chloride-based, polyurethane-based, polyester-based, polyamide-based, polybutadiene-based, trans-polyisoprene-based, fluororubber-based, chlorinated polyethylene-based, etc. One or more selected from these can be used in combination. Preferably, as the thermoplastic resin, a polyester or a material containing the same is used.

[0064] In addition to the above binder, for example, a colorant for coloring the fiber, an aggregation inhibitor for suppressing the aggregation of the fiber and the binder, a flame retardant for making the fiber etc. difficult to burn, a paper strength enhancer for enhancing the paper strength, etc. may be included.

[0065] In such a base material layer 2, when the basis weight of the first layer 21, that is, the basis weight of the material constituting the first layer 21 is A1 (g / cm 2 ) and the basis weight of the second layer 22, that is, the basis weight of the material constituting the second layer 22 is A2 (g / cm 2 ), A2 < A1 is satisfied.

[0066] According to such a configuration, as shown in FIG. 2, the ink 100 applied to the second layer 22 is quickly and sufficiently diffused far in the plane direction on the second layer 22 and also diffuses in the thickness direction of the layer and migrates to the first layer 21. Further, once the ink 100 has migrated to the first layer 21, it migrates to the absorption layer 3 in contact with the first layer 21 without returning to the second layer 22 side, and is absorbed and held by the absorption layer 3. Therefore, the ink 100 can be quickly absorbed and held over a wider range of the liquid absorber 1, and the absorption characteristics of the ink 100 as the entire liquid absorber 1 can be made even more excellent.

[0067] In particular, since the ink 100 is quickly and sufficiently diffused far in the plane direction in the second layer 22, the ink 100 is uniformly absorbed and held throughout the absorption layer 3. Therefore, the liquid absorber 1 can quickly absorb and hold more ink 100 without delay in the migration and diffusion of the ink 100 inside it.

[0068] A1 is not particularly limited, but for example, it is preferably 0.02 g / cm 2 or more and 2.0 g / cm 2 or less, more preferably 0.05 g / cm 2 or more and 1.5 g / cm 2 or less.

[0069] A2 is not particularly limited, but for example, it is preferably 0.01 g / cm 2 or more and 1.8 g / cm 2 or less, more preferably 0.04 g / cm 2 or more and 1.2 g / cm 2 or less.

[0070] By setting A1 and A2 within the above numerical ranges, the above-described effects obtained by satisfying A2 < A1 can be more significantly exhibited.

[0071] The ratio A1 / A2 of A1 to A2 is preferably 1.1 or more and 5 or less, more preferably 1.2 or more and 4 or less. Thereby, the above-described effects obtained by satisfying A2 < A1 can be more surely and remarkably exhibited.

[0072] Further, the density of the first layer 21, that is, the density of the material constituting the first layer 21 is B1 (g / cm 3 ), and when the density of the second layer 22, that is, the density of the material constituting the second layer 22 is B2 (g / cm 3 ), it is preferable to satisfy B2 < B1.

[0073] Thereby, the ink 100 applied to the second layer 22 rapidly and sufficiently diffuses far in the plane direction on the second layer 22 and also diffuses in the thickness direction of the layer and migrates to the first layer 21. Further, the ink 100 that has once migrated to the first layer 21 migrates to the absorption layer 3 in contact with the first layer 21 without returning to the second layer 22 side and is absorbed and held by the absorption layer 3. Therefore, the ink 100 can be rapidly absorbed and held in a wider range of the liquid absorber 1, and the absorption characteristics of the ink 100 as the entire liquid absorber 1 can be made more excellent.

[0074] Further, B1 is not particularly limited. For example, it is preferably 0.02 g / cm 3 or more and 0.8 g / cm 3 or less, more preferably 0.06 g / cm 3 or more and 0.5 g / cm 3 or less.

[0075] Further, B2 is not particularly limited. For example, it is preferably 0.01 g / cm 3 or more and 0.5 g / cm 3 or less, more preferably 0.05 g / cm 3 or more and 0.3 g / cm 3 or less.

[0076] By setting B1 and B2 within the above numerical ranges, the above-described effects obtained by satisfying B2 < B1 can be more remarkably exhibited.

[0077] The ratio B1 / B2 of B1 to B2 is preferably 1.3 or more and 4 or less, more preferably 1.5 or more and 2 or less. Thereby, the above-described effects obtained by satisfying B2 < B1 can be more surely and remarkably exhibited.

[0078] Note that the present invention is not limited to the above configuration, and B1 = B2 or B1 < B2 may be possible.

[0079] Further, when the thickness (average thickness) of the first layer 21 is T1 (mm) and the thickness (average thickness) of the second layer 22 is T2 (mm), it is preferable to satisfy T2 < T1. Thereby, the ink 100 applied to the second layer 22 is more effectively diffused in the plane direction in the second layer 22, and the ink 100 transferred to the first layer 21 can be more effectively prevented from flowing back to the second layer 22 side. Therefore, the absorption characteristics of the ink 100 as the entire liquid absorber 1 can be made more excellent.

[0080] T1 is not particularly limited, but for example, it is preferably 0.2 mm or more and 10 mm or less, more preferably 0.6 mm or more and 5 mm or less.

[0081] T2 is not particularly limited, but for example, it is preferably 0.1 mm or more and 8 mm or less, more preferably 0.5 mm or more and 4 mm or less.

[0082] By setting T1 and T2 within the above numerical ranges, the above-described effects obtained by satisfying T2 < T1 can be more remarkably exhibited.

[0083] The ratio T1 / T2 of T1 to T2 is not particularly limited, but is preferably 1.2 or more and 5 or less, more preferably 1.5 or more and 3 or less. Thereby, the effect that the ink 100 can be quickly and sufficiently diffused far in the plane direction in the second layer 22 and the ink 100 can be quickly transferred to the first layer 21 can be more remarkably exhibited.

[0084] Note that the present invention is not limited to the above configuration, and T1 = T2 or T1 < T2 may be used.

[0085] Also, when the diffusion rate of the ink 100 in the plane direction of the first layer 21 is C1 (mm / s) and the diffusion rate of the ink 100 in the plane direction of the second layer 22 is C2 (mm / s), it is preferable that C1 < C2. Thereby, the ink 100 applied to the second layer 22 can be diffused more rapidly and farther in the plane direction on the second layer 22. Therefore, the absorption characteristics of the ink 100 as the entire liquid absorber 1 can be further improved.

[0086] C1 is not particularly limited, but for example, it is preferably 0.5 mm / s or more and 8 mm / s or less, and more preferably 1 mm / s or more and 6 mm / s or less.

[0087] C2 is not particularly limited, but for example, it is preferably 1 mm / s or more and 10 mm / s or less, and more preferably 2 mm / s or more and 8 mm / s or less.

[0088] By setting C1 and C2 within the above numerical ranges and satisfying C1 < C2, the above-described effects can be more significantly exhibited.

[0089] The ratio C2 / C1 of C1 to C2 is not particularly limited, but it is preferably 1.2 or more and 4 or less, and more preferably 1.5 or more and 2 or less. Thereby, the effect that the ink 100 can be rapidly and sufficiently diffused far in the plane direction in the second layer 22 and the ink 100 can be rapidly transferred to the first layer 21 can be more significantly exhibited.

[0090] Note that the values of A1, A2, B1, B2, T1, T2, C1, and C2 are values obtained excluding the sealing portion 4 described later.

[0091] As described above, the liquid absorber 1 includes an absorption layer 3 having a water-absorbing resin 30 and having liquid-absorbing properties, and a base material layer 2 laminated on at least one surface side of the absorption layer 3, in this embodiment, on both surface sides, and having liquid permeability. The base material layer 2 has a first layer 21 containing cellulose and a second layer 22 located on the side opposite to the absorption layer 3 of the first layer 21 and having a basis weight different from that of the first layer 21. Also, when the basis weight of the first layer 21 is A1 (g / cm 2 ), and the basis weight of the second layer 22 is A2 (g / cm 2 ), A2 < A1 is satisfied. Thereby, the absorption characteristics of the liquid, for example, the ink 100, of the liquid absorber 1 can be made excellent. Since the ink 100 diffuses quickly and sufficiently far in the plane direction in the base material layer 2, particularly in the first layer 21 constituting the base material layer 2, the ink 100 is uniformly absorbed and held throughout the absorption layer 3. As a result, the absorption capacity of the ink 100 of the liquid absorber 1 can be increased.

[0092] Note that an intermediate layer may be formed between the first layer 21 and the second layer 22. Examples of the intermediate layer include a fixing layer that fixes the first layer 21 and the second layer 22, and a gap forming layer that forms a gap between the first layer 21 and the second layer 22.

[0093] Further, the liquid absorber 10 includes the liquid absorber 1 and a container 6 that houses the liquid absorber 1 and has an opening 60 that is a liquid supply portion to which the ink 100 as a liquid is supplied. Thereby, the liquid absorber 1 having excellent absorption characteristics for a liquid, for example, the ink 100, can be stably arranged at a desired position, for example, inside a printing apparatus or the like. Such a liquid absorber 10 can absorb and hold a sufficient amount of liquid, and thus is advantageous for collecting waste liquid such as waste ink.

[0094] Also, the configuration of the liquid supply portion is appropriately determined according to the type, shape, etc. of the container 6. When the container 6 is, for example, a bottle, the mouth portion of the bottle serves as the liquid supply portion.

[0095] In the present embodiment, the container 6 is composed of a rigid tray. However, the present invention is not limited to this. For example, the container 6 may be a rigid or flexible bottle, a housing, or a flexible bag.

[0096] Also, when the density of the first layer 21 is B1 (g / cm 3 ) and the density of the second layer 22 is B2 (g / cm 3 ), B2 < B1 is satisfied. Thereby, in the base material layer 2, the ink 100 can be diffused more rapidly and farther in the plane direction. Therefore, the absorption characteristics of the ink 100 of the entire liquid absorber 1 can be made even more excellent.

[0097] Also, when the thickness of the first layer 21 is T1 (mm) and the thickness of the second layer 22 is T2 (mm), T1 / T2 is 1.2 or more and 5 or less. Thereby, in the base material layer 2, the ink 100 can be diffused more rapidly and farther in the plane direction. Therefore, the absorption characteristics of the ink 100 of the entire liquid absorber 1 can be made even more excellent.

[0098] Also, when the liquid diffusion rate of the first layer 21 in the plane direction is C1 (mm / s) and the liquid diffusion rate of the second layer 22 in the plane direction is C2 (mm / s), C1 < C2 is satisfied. Thereby, in the base material layer 2, the ink 100 can be diffused more rapidly and farther in the plane direction. Therefore, the absorption characteristics of the ink 100 of the entire liquid absorber 1 can be made even more excellent.

[0099] Also, the base material layer 2 is laminated on each of the upper surface 31 side, which is one surface side of the absorption layer 3, and the lower surface 32 side, which is the other surface side. Thereby, the liquid, that is, the ink 100 can be absorbed from any surface side of the liquid absorber 1, and the versatility is excellent.

[0100] In other words, when storing the liquid absorber 1 in the container 6, it can be put into the container 6 without worrying about the front and back of the liquid absorber 1, and it is excellent in compatibility, operability, and versatility.

[0101] The structure of the base material layer 2 on the upper surface 31 side and the structure of the base material layer 2 on the lower surface 32 side may be the same or different. In the latter case, when the constituent materials of the first layer 21 and the second layer 22 are different, examples include cases where at least one of the A1, A2, B1, B2, T1, T2, C1, and C2 is different.

[0102] In the present invention, the structure may have the base material layer 2 only on one surface side of the absorption layer 3. In this case, the other surface side of the absorption layer 3 may be, for example, a base material layer composed of a first layer and a second layer that do not satisfy A2 < A1, a single layer or sheet having liquid permeability, a sheet having liquid impermeability, a plate material, a wall portion, the bottom surface inside the container 6, etc., or any configuration such as an open opening.

[0103] As shown in FIGS. 1 and 3, the liquid absorber 1 has a sealing portion 4 that seals the base material layer 2 on the upper surface 31 side of the absorption layer 3 and the base material layer 2 on the lower surface 32 side. The sealing portion 4 is also a portion where the edges of the first layer 21 and the second layer 22 of both base material layers 2 are joined. In the present embodiment, the entire circumference of the edges of the base material layer 2 on the upper surface 31 side and the base material layer 2 on the lower surface 32 side are joined and sealed by the sealing portion 4. As shown in FIG. 3, this sealing portion 4 forms a frame shape in plan view. By providing such a sealing portion 4, it is possible to prevent or suppress the unintended outward flow of the water-absorbing resin 30 or the absorbed ink 100 in the absorption layer 3.

[0104] Note that the sealing portion 4 is not limited to the case where it is formed on the entire circumference of the edges of both base material layers 2, and a part of the entire circumference of the edges may be missing. As a result, the liquid absorber 1 has a part where the base material layers 2 are open.

[0105] The joining method of the sealing portion 4 is not particularly limited, and examples include fusion such as heat fusion, ultrasonic fusion, and high-frequency fusion, adhesion using an adhesive, thermocompression bonding, double-sided tape fixing, sewing, pin fixing, stapler fixing, clip fixing, etc., and one or more of these can be used in combination.

[0106] In the illustrated configuration, the sealing portion 4 is formed by thermocompression bonding. This increases the fiber density in the sealing portion 4. This effectively prevents or suppresses the outflow of the absorbed ink 100 from the sealing portion 4.

[0107] Furthermore, since at least one of the base layers 2 contains the binder as described above, the base layers 2 can be bonded by fusion such as thermal fusion. Furthermore, by appropriately selecting the conditions of the type, melting point, particle size, and amount of the binder contained in each base layer 2, the bonding strength can be easily adjusted.

[0108] When the sealing portion 4 is formed by bonding using an adhesive, the adhesive to be used is not particularly limited, and a water-soluble adhesive, an organic adhesive, etc. can be used, but among them, a water-soluble adhesive is preferable.

[0109] Examples of water-soluble adhesives include proteins such as casein, soy protein, and synthetic protein; various starches such as starch and oxidized starch; polyvinyl alcohols including modified polyvinyl alcohols such as polyvinyl alcohol, cationic polyvinyl alcohol, and silyl-modified polyvinyl alcohol; cellulose derivatives such as carboxymethyl cellulose and methyl cellulose; aqueous polyurethane resins; and aqueous polyester resins.

[0110] 3, the width W of the sealing portion 4 in a plan view is not particularly limited, but is preferably, for example, 2 mm to 35 mm, and more preferably 5 mm to 24 mm. When the width W of the sealing portion 4 is in this range, the edge of the base layer 2 can be sealed necessary and sufficiently.

[0111] The width W of the sealing portion 4 is preferably uniform over the entire periphery of the sealing portion 4, but is not limited to this.

[0112] The liquid absorber 1 as described above can be manufactured, for example, by the following manufacturing method.

[0113] First, as shown in FIG. 4, a nonwoven fabric is prepared as the second layer 22, and defibrated cellulose fiber material 7 is deposited on the second layer 22 to obtain a laminate 9 in which a deposit 8 is laminated on the second layer 22.

[0114] Next, the laminate 9 is pressed with a pressure roller or the like (not shown) to compress the deposit 8 on the second layer 22, thereby forming the first layer 21. In this way, the base layer 2 can be obtained from the laminate 9. Note that, when the deposit 8 contains a binder, heating may be performed simultaneously with pressing. By this method, two base layers 2 are produced.

[0115] Next, as shown in Fig. 5, moisture 11 is applied to the surface of the first layer 21 of one of the base layers 2 by a spray bottle or the like, and then, as shown in Fig. 6, particles of the water-absorbent resin 30 are supplied onto the first layer 21. Then, by drying this, an absorbent layer 3 composed of the water-absorbent resin 30 is formed on the first layer 21, and thus a laminate 12 in which the absorbent layer 3 and one of the base layers 2 are laminated can be obtained.

[0116] 7, the laminate 12 is placed with the absorbent layer 3 on the upper side, and the other base material layer 2 is laminated onto the surface of the absorbent layer 3 opposite to the base material layer 2 (upper side) with the first layer 21 facing the absorbent layer 3, and then dried. Moisture is added in advance to the surface of the other (upper) base material layer 2 to be laminated, particularly the bonding surface.

[0117] 7, the portions of both base material layers 2 where the sealed portions 4 are to be formed, i.e., the entire periphery of the edges, are pressed from above and below using a pressure block 5 to form the sealed portions 4. In this way, the liquid absorbent 1 can be obtained.

[0118] By replacing the pressure block 5 with a heating and pressure block, a thermocompression-bonded sealing portion 4 can be formed.

[0119] Although the liquid absorber and the liquid absorber of the present invention have been described above with reference to the illustrated embodiment, the present invention is not limited thereto, and each part constituting the liquid absorber and the liquid absorber can be replaced with any other part capable of exerting the same function. Also, any other part may be added. [Explanation of symbols]

[0120] Reference Signs List 1...liquid absorber, 2...base material layer, 3...absorbent layer, 4...sealing portion, 5...pressurizing block, 6...container, 7...defibrated material, 8...deposit, 9...laminated body, 10...liquid absorber, 11...moisture, 12...laminated body, 21...first layer, 22...second layer, 30...water-absorbent resin, 31...upper surface, 32...lower surface, 60...opening, 100...ink

Claims

1. An absorbent layer having a water-absorbing resin and liquid-absorbing properties, The absorbent layer comprises a base layer having liquid permeability, which is laminated on at least one side of the absorbent layer, The substrate layer comprises a first layer containing cellulose and a second layer located on the opposite side of the absorbent layer of the first layer, and having a different basis weight from the first layer. The basis weight of the first layer is A1 (g / cm²). ２ ) and the basis weight of the second layer is A2 (g / cm²). ２ When this is the case, A2 < A1 is satisfied, A liquid absorbent characterized in that, when the diffusion rate of the liquid in the planar direction of the first layer is C1 (mm / s) and the diffusion rate of the liquid in the planar direction of the second layer is C2 (mm / s), the condition C1 < C2 is satisfied.

2. The density of the first layer is B1 (g / cm³). ３ ) and the density of the second layer is B2 (g / cm³). ３ The liquid absorbent according to claim 1, satisfying B2 < B1 when B2 < B1.

3. The liquid absorbent according to claim 1, wherein when the thickness of the first layer is T1 (mm) and the thickness of the second layer is T2 (mm), T1 / T2 is 1.2 or more and 5 or less.

4. The liquid absorbent according to any one of claims 1 to 3, wherein the second layer is a nonwoven fabric.

5. The liquid absorbent according to any one of claims 1 to 3, wherein the base material layer is laminated on one side and the other side of the absorbent layer, respectively.

6. A liquid absorbent according to any one of claims 1 to 3, having a sealing portion that seals the edge of the base material layer on one side and the edge of the base material layer on the other side.

7. A liquid absorbent according to any one of claims 1 to 3, A liquid absorber characterized by comprising a container having a liquid supply section for housing the liquid absorbent and for supplying liquid.

Images