JP6766915B2 - container - Google Patents

Description

The present invention relates to a container. Specifically, the present invention relates to a container provided with an absorption layer containing fine fibrous cellulose.

Paper containers and plastic containers are widely used as containers for filling foods and the like. For example, cup-shaped containers for filling beverages and cup-shaped containers for filling and packaging foods such as yogurt and ice cream are often used. As such a container, a paper container having a water-repellent laminated layer and a single-layer plastic container are widely distributed.

In recent years, variously devised containers have been developed to enhance functionality. For example, Patent Document 1 discloses a composite cup including an inner cup made of a plastic film and an outer cup made of paper. Here, by superimposing the inner cup and the outer cup, it is possible to impart heat insulation performance, heat retention performance and cold retention performance, and further, a device is made to prevent dew condensation from being dissipated to the surrounding environment.

Further, Patent Documents 2 and 3 disclose a paper cup provided with a paper base material and a barrier layer containing cellulose fibers. Here, it is studied to enhance the barrier property of a paper cup by using a chemically treated cellulose fiber as a barrier layer.

Japanese Unexamined Patent Publication No. 2014-221656 JP-A-2017-190541 JP-A-2017-190544

When the container is filled with a cold beverage or the like as the content, dew condensation occurs on the outer peripheral surface of the container. Such condensed water has become a problem because it adheres to the user's hand when holding the container or is unintentionally released to the surrounding environment.

In the prior art, for example, a technique has been proposed in which a structure including an inner cup and an outer cup is provided to prevent dew condensation water from being released to the surrounding environment, but dew condensation occurs (condensation water). The technology for suppressing adhesion) is not disclosed.
Therefore, an object of the present invention is to provide a new form of container capable of suppressing the occurrence of dew condensation.

As a result of diligent studies to solve the above problems, the present inventors have made fibers in the absorption layer in a container provided with a base material layer and an absorption layer arranged on the outer surface side of the base material layer. It has been found that a container having a width of 1000 nm or less and containing a phosphorous acid group or a fibrous cellulose having a substituent derived from a phosphorous acid group can obtain a container in which the occurrence of dew condensation is suppressed.
Specifically, the present invention has the following configuration.

[1] A base material layer and an absorption layer are provided.
The absorption layer contains fibrous cellulose having a fiber width of 1000 nm or less and having a phosphorous acid group or a substituent derived from a phosphorous acid group.
The absorption layer is a container arranged on the outer surface side of the base material layer.
[2] Consists of a body member and a bottom member
The container according to [1], wherein the body member includes a base material layer and an absorption layer.
[3] The container according to [1] or [2], wherein the base material layer contains at least one selected from pulp, resin, glass and metal.
[4] The absorption layer contains fibrous cellulose having a fiber width of 1000 nm or less and having a phosphorous acid group or a substituent derived from a phosphorous acid group, and a hydrophilic polymer [1] to [3]. ] The container described in any of.
[5] The container according to [4], wherein the hydrophilic polymer is at least one selected from polyvinyl alcohol and polyethylene oxide.
[6] The container according to any one of [1] to [5], wherein the absorption layer has a thickness of 10 μm or more.
[7] The container according to any one of [1] to [6], wherein the water absorption rate calculated by the following formula 1 in the region (X) in which the absorption layer is laminated on the base material layer is 80% or more.
Formula 1: water absorption _{(%) = (W B -W} A) / W A × 100
Here, W _B represents the weight of the region (X) after immersion for 24 hours in deionized water, W _A represents the weight of the region (X) prior to immersion in deionized water.
[8] The container according to any one of [1] to [7], wherein the haze of the region (X) in which the absorption layer is laminated on the base material layer is 70% or less.
[9] The container according to any one of [1] to [8], wherein the absorption layer is laminated on the base material layer via an adhesive layer.
[10] Further provided with a transparent layer
The container according to any one of [1] to [9], wherein the permeable layer is arranged on the outer surface side of the absorbing layer.
[11] The container according to any one of [1] to [10], wherein a part of the base material layer is exposed on the outer surface.
[12] The container according to any one of [1] to [11] for accommodating cold articles.

According to the present invention, it is possible to obtain a container in which the occurrence of dew condensation is suppressed.

FIG. 1 is a schematic view illustrating an embodiment of the container of the present invention. FIG. 2 is a plan view illustrating the layer structure of the container of the present invention. FIG. 3 is a schematic view illustrating an embodiment of the container of the present invention. FIG. 4 is a graph showing the relationship between the amount of NaOH added dropwise and the pH of the fibrous cellulose-containing slurry having a phosphoric acid group. FIG. 5 is a plan view illustrating the layer structure of the container of the present invention. FIG. 6 is a plan view illustrating the layer structure of the container of the present invention.

Hereinafter, the present invention will be described in detail. The description of the constituent elements described below may be based on typical embodiments or specific examples, but the present invention is not limited to such embodiments.

(container)
The present invention relates to a container including a base material layer and an absorption layer. Here, the absorption layer contains fibrous cellulose having a fiber width of 1000 nm or less and having a phosphorous acid group or a substituent derived from a phosphorous acid group, and the absorption layer is arranged on the outer surface side of the base material layer. Has been done.

FIG. 1 is a schematic view illustrating an embodiment of the container 100 of the present invention. As shown in FIG. 1, the container 100 includes a base material layer 20 on the inner surface side and an absorption layer 30 on the outer surface side. In FIG. 1, since the layer structure of the base material layer 20 and the absorption layer 30 is drawn so as to be easy to understand, the thickness and the ratio of the thickness of each layer are not necessarily the same as the actual container structure. An accommodating portion for accommodating the contents is formed inside the base material layer 20. The base material layer 20 is preferably provided on the innermost surface so as to be in direct contact with the contents. Therefore, it is preferable that the surface of the base material layer 20 on the accommodating portion side is provided with a layer capable of exhibiting water repellency.

FIG. 2 is a plan view of the container 100 of the present invention as viewed from above. In FIG. 2, since the layer structure of the base material layer 20 and the absorption layer 30 is drawn so as to be easy to understand, the thickness and the ratio of the thickness of each layer are not necessarily the same as the actual container structure.
As shown in FIG. 2, the absorption layer 30 is provided on the outer surface side of the base material layer 20. As shown in FIG. 2, the absorption layer 30 may be laminated so as to be in direct contact with the base material layer 20. Further, as shown in FIG. 2, the absorption layer 30 may be a layer constituting the outermost surface of the container 100. As will be described later, another layer may be provided between the absorption layer 30 and the base material layer 20. For example, an adhesive layer 25 may be provided between the absorption layer 30 and the base material layer 20. Further, as will be described later, a transmission layer 40 may be further provided on the outer surface side of the absorption layer 30.

Since the container of the present invention has the above configuration, it is possible to suppress the occurrence of dew condensation on the outer peripheral surface of the container even when cold articles such as cold beverages are stored in the container storage portion. it can. This is because the absorption layer of the container has a function of absorbing condensed water. Since the absorption layer has a function of absorbing the dew condensation water, it can absorb the dew condensation water generated on the outer peripheral surface of the container, thereby suppressing the dew condensation water from adhering to the outer peripheral surface of the container. As described above, the container of the present invention can suppress the occurrence of dew condensation, and can reduce the discomfort caused by the dew condensation water getting on the hand or dripping during use.

As described above, since the container of the present invention includes an absorption layer capable of absorbing condensed water, it is suitable for accommodating cold articles as contents. That is, the container of the present invention is preferably used for storing cold articles. Above all, the container of the present invention is particularly preferably used for cold food storage and cold beverage storage.

Further, the container of the present invention is a container in which a base material layer and an absorption layer are integrated. That is, the base material layer and the absorption layer constitute one laminated body, and the laminated body is formed into a container shape. Therefore, the container of the present invention is easy to manufacture, and has advantages such as not taking up a storage space because it can be designed to be compact.

Since the container of the present invention has the above-mentioned structure, it is also excellent in heat retention and heat insulation. That is, the absorption layer has a function of making it difficult to convey the heat of the contents to the handle of the user when a hot beverage or the like is stored in the storage portion, and also has a function of keeping the contents warm so as not to cool down. Further, in the container of the present invention, the absorbent layer can also exert a non-slip function. Since the absorbent layer is easily adapted to the user's handle, it is possible to prevent the container from slipping off the handle.

As shown in FIG. 1, the container 100 of the present invention is preferably composed of a body member and a bottom member. As described above, the container 100 of the present invention preferably has an opening on the upper surface facing the bottom surface. The container 100 may further include a lid member. In such a case, the lid member is preferably engaged or joined to the body member so as to cover the opening.
The container 100 is preferably formed by combining at least two members such as a body member and a bottom member, but may be composed of a member that is not distinguished into a body member and a bottom member. For example, the container 100 may have a bowl shape or a rectangular parallelepiped shape composed of a series of members, or may have an inverted triangular pyramid shape composed of a plurality of triangular members assembled.

When the container 100 is composed of a body member and a bottom member, the shape of the bottom member is not particularly limited. The shape of the bottom member is preferably circular as shown in FIG. 1, but may be quadrangular, triangular, elliptical or the like. In such a case, the body member constitutes a side wall (side surface) along the shape of the bottom member. For example, when the bottom member is circular, the body member becomes a side wall (side surface) of the circular bottom member and is assembled in a tubular shape.

When the container is composed of a body member and a bottom member, it is preferable that the body member includes a base material layer and an absorption layer. In this case, the bottom member may be composed of only the base material layer. That is, the absorption layer may be provided only on the side surface of the container. In this case, the base material layer of the bottom member is exposed to the outer surface on the bottom surface.

When the container is composed of a body member and a bottom member, the absorption layer 30 may be provided on all of the body members as shown in FIG. 1, and as shown in FIG. The absorption layer 30 may be provided on a part of the body member. When the absorption layer 30 is provided on a part of the body member, a part of the base material layer 20 may be exposed on the outer surface of the side surface. When the absorption layer 30 is provided on a part of the body member, the dew condensation generated in the portion without the absorption layer 30 is absorbed by the partially provided absorption layer 30 to dissipate to the surrounding environment. It can also be prevented. In FIG. 3, the absorption layer 30 is provided below the body member, and the base material layer 20 is exposed above the body member. As described above, the absorption layer 30 is preferably provided in a region from the bottom of the body member to an arbitrary height. In this case, the arbitrary height at which the absorption layer 30 is provided is preferably 50% or more, more preferably 60% or more, and 70% or more the height of the container. It is even more preferable that the height is high. As a result, the absorption layer 30 can sufficiently absorb the condensed water, and the manufacturing cost of the container 100 can be suppressed.
In FIG. 3, since the layer structure of the base material layer 20 and the absorption layer 30 is drawn so as to be easy to understand, the thickness and the ratio of the thickness of each layer are not necessarily the same as the actual container structure.

The absorption layer may be provided only in the central region in the height direction of the body member. For example, an absorption layer may be provided in the vicinity of the gripped portion of the user in the body member. Further, the absorption layer may be provided intermittently along the circumferential direction of the outer peripheral surface of the body member and in the height direction. That is, the absorption layer may be provided on the body member in a striped shape. Further, the absorption layer may be provided on the body member in a pattern, for example, may be provided in a polka dot pattern or a lattice pattern. In such a case, the absorption layer is preferably provided in a region of 40% or more, more preferably 50% or more, and 60% or more of the surface area of the body member. It is more preferable that the area is provided. As a result, the absorbing layer can exert a non-slip function while absorbing the condensed water more effectively.

The flat area of the opening of the container and the flat area of the bottom member may be the same or different. In particular, when the container is used for accommodating cold beverages, it is preferable that the flat area of the opening> the flat area of the bottom member, as shown in FIG.

In the container of the present invention, the absorbent layer has excellent water absorption. Therefore, the absorption layer can absorb the dew condensation water generated when the cold article is contained as the content, and thereby it is possible to suppress the dew condensation water from adhering to the container surface. Specifically, the water absorption rate of the container calculated by the following formula 1 in the region (X) where the absorption layer is laminated on the base material layer is preferably 80% or more, and more preferably 90% or more. It is more preferably 100% or more, further preferably 120% or more, further preferably 180% or more, and particularly preferably 200% or more. The upper limit of the water absorption rate is not particularly limited, and may be, for example, 5000%.
Formula 1: water absorption _{(%) = (W B -W} A) / W A × 100
Here, W _B represents the weight of the region (X) after immersion for 24 hours in deionized water, W _A represents the weight of the region (X) prior to immersion in deionized water. When calculating the water absorption rate in the present specification, for example, the portion of the container where the base material layer and the absorption layer are laminated is cut out into a 5 cm square to form a test piece, and the weight before and after the test piece is immersed in ion-exchanged water. Is calculated by measuring. The size of the test piece used when calculating the water absorption rate is not particularly limited.

In the container of the present invention, the absorbent layer has excellent transparency. Therefore, by using a transparent material for the base material layer, the transparency of the entire container can be increased and the haze value of the container can be lowered. In such a case, the contents contained in the accommodating portion can be visually recognized from the outside, and the design can be enhanced. For example, the haze value of the region (X) in which the absorption layer is laminated on the base material layer on any one surface of the container may be 70% or less, 60% or less, or 30% or less. It may be 10% or less.
Here, the haze value of the region (X) is obtained by cutting out a portion where the base material layer and the absorption layer are laminated, for example, into a 5 cm square to obtain a test piece, and using a haze meter (HM-150, manufactured by Murakami Color Technology Research Institute). In use, it is measured according to JIS K 7136. The size of the test piece used for measuring the haze is not particularly limited.

The haze value of the absorption layer is also preferably within the above range. That is, it is preferable that the absorption layer has high transparency. As a result, for example, even when characters or patterns are printed on the base material layer, the absorption layer does not reduce the visibility of the characters or patterns. When measuring the haze value of the absorbent layer, after peeling the absorbent layer from the container, a test piece cut into a 5 cm square was used, for example, using a haze meter (HM-150, manufactured by Murakami Color Technology Research Institute). Haze with D65 light source is measured according to JIS K 7136.

(Base layer)
The container of the present invention includes a base material layer. The base material layer is preferably provided on the innermost surface so as to be in direct contact with the contents. For this reason, it is preferable that a layer capable of exhibiting water repellency is provided on the surface of the base material layer on the accommodating portion side.

The base material layer is preferably a layer containing at least one selected from pulp, resin, glass and metal. Above all, the base material layer is more preferably a layer containing at least one selected from pulp and resin. When the base material layer is made of resin, the light transmittance of the base material layer can be increased, and thus the haze value of the container can be lowered. As a result, the visibility of the contents of the container can be enhanced and the design can be enhanced.

When the base material layer is a layer containing pulp, it is preferable to use a multilayer body in which at least one surface of the paper layer containing pulp as a main component is laminated with a resin component as the base material layer. In this case, examples of the resin component for laminating include polyolefin-based resin, epoxy-based resin, urethane-based resin, isocyanate-based resin, polyester-based resin, plant-derived material (bioplastic), polyethylene-based resin, polypropylene-based resin, and the like. be able to. Of these, polyethylene-based resins and polypropylene-based resins that can be heat-sealed are preferably used. Examples of the polyethylene-based resin include low-density polyethylene resin (LDPE), medium-density polyethylene resin (MDPE), high-density polyethylene resin (HDPE), linear low-density polyethylene (LLDPE), and the like. (LLDPE) is particularly preferably used. Examples of polypropylene-based resins include polypropylene resins, propylene-ethylene random copolymers, and propylene-ethylene block copolymers.

When laminating the resin components as described above, for example, a wet lamination method, a dry lamination method, a solvent-free lamination method, a thermal lamination method, a melt extrusion lamination method and the like can be adopted. In order to enhance the adhesion of the resin component, the paper layer may be subjected to known surface treatments such as corona treatment, ozone treatment, plasma treatment, glow discharge treatment, and oxidation treatment using chemicals in advance. Further, a primer coat layer, an anchor coat layer, an adhesive layer and the like may be provided between the paper layer and the laminate layer of the resin component.

In this specification, pulp refers to a cellulose fiber component having a fiber width of more than 1000 nm, and is distinguished from fine fibrous cellulose described later. The base material layer may contain fine fibrous cellulose, but the content of the fine fibrous cellulose is preferably 10% by mass or less, and more preferably 5% by mass or less, based on the total mass of the base material layer. It is preferably 0% by mass or less, and more preferably 0% by mass or less.

When the base material layer is a layer containing a resin, the resin type is not particularly limited, and examples thereof include polystyrene-based resin, polyolefin-based resin, polyester-based resin, and acrylic-based resin. The resin constituting the base material layer is preferably a highly transparent resin type.

When the base material layer is a layer containing a metal, the metal type is not particularly limited, and examples thereof include stainless steel, iron, copper, and aluminum.

The thickness of the base material layer is not particularly limited, but for example, it is preferably 10 μm or more, more preferably 50 μm or more, further preferably 100 μm or more, and the thickness of the base material layer. Is preferably 5000 μm or less.

A printing layer may be provided on the outer surface of the base material layer. For example, characters, patterns, etc. may be printed on the outer surface of the base material layer. The printing layer is provided by a known method according to the material of the outer surface of the base material layer.

(Absorption layer)
The container of the present invention is provided with an absorption layer on the outer surface side of the above-mentioned base material layer. The absorption layer contains fibrous cellulose having a fiber width of 1000 nm or less and having a phosphorous acid group or a substituent derived from a phosphorous acid group. In the present specification, fibrous cellulose having a fiber width of 1000 nm or less is also referred to as fine fibrous cellulose.

The absorption layer preferably has a fiber width of 1000 nm or less and further contains a hydrophilic polymer in addition to a phosphite group or a fibrous cellulose having a substituent derived from a phosphorous acid group. Examples of the hydrophilic polymer include carboxyvinyl polymer, polyvinyl alcohol, alkyl methacrylate / acrylic acid copolymer, polyvinylpyrrolidone, sodium polyacrylate, polyethylene glycol, diethylene glycol, triethylene glycol, polyethylene oxide, propylene glycol, and dipropylene glycol. , Polypropylene glycol, isoprene glycol, hexylene glycol, 1,3-butylene glycol, polyacrylamide and the like. Among them, the hydrophilic polymer is preferably at least one selected from polyvinyl alcohol and polyethylene oxide.

The content of the fine fibrous cellulose contained in the absorption layer is preferably 1% by mass or more, more preferably 2% by mass or more, and 3% by mass or more, based on the total mass of the absorption layer. Is even more preferable. The content of the fine fibrous cellulose is preferably 90% by mass or less, more preferably 70% by mass or less, and further preferably 60% by mass or less, based on the total mass of the absorption layer. preferable.

When the absorbing layer contains a hydrophilic polymer, the content of the hydrophilic polymer contained in the absorbing layer is preferably 10% by mass or more, preferably 15% by mass or more, based on the total mass of the absorbing layer. More preferably, it is more preferably 20% by mass or more. The content of the hydrophilic polymer is preferably 99.5% by mass or less, more preferably 99.0% by mass or less, and 95.0% by mass or less with respect to the total mass of the absorption layer. Is more preferable.

The absorption layer may contain any component other than the above-mentioned components. Optional components include, for example, surfactants, organic ions, coupling agents, inorganic layered compounds, inorganic compounds, leveling agents, preservatives, defoamers, organic particles, lubricants, antistatic agents, UV protection agents, etc. Examples thereof include dyes, pigments, stabilizers, magnetic powders, orientation promoters, plasticizers, dispersants, and cross-linking agents.

The content of the optional component contained in the absorption layer is preferably 40% by mass or less, more preferably 30% by mass or less, and more preferably 20% by mass or less, based on the total mass of the absorption layer. Is even more preferable.

The absorption layer is excellent in water absorption, and the water absorption rate of the absorption layer calculated by the following formula 1 is preferably 80% or more, more preferably 90% or more, and further preferably 100% or more. It is more preferably 120% or more, further preferably 180% or more, and particularly preferably 200% or more. The upper limit of the water absorption rate is not particularly limited and may be, for example, 1500%.
Formula 1: water absorption _{(%) = (W b -W} a) / W a × 100
Here, W _b represents the weight of the absorption layer after being immersed in ion-exchanged water for 24 hours, and W _a represents the weight of the absorption layer before being immersed in ion-exchanged water. When calculating the water absorption rate in the present specification, for example, the absorption layer is peeled off from the container, and then the weight of the absorption layer cut into 5 cm squares before and after being immersed in ion-exchanged water is measured. To do. The size of the test piece used when calculating the water absorption rate is not particularly limited.

The haze value of the absorption layer is preferably 70% or less, more preferably 60% or less, further preferably 30% or less, and particularly preferably 10% or less. The haze value of the absorption layer was adjusted to JIS K 7136 using, for example, a haze meter (HM-150, manufactured by Murakami Color Technology Research Institute) for a test piece cut into 5 cm squares after the absorption layer was peeled off from the container. It is a value which measured the haze by the D65 light source according to. The size of the test piece used for measuring the haze is not particularly limited.

The thickness of the absorption layer is preferably 10 μm or more, more preferably 15 μm or more, further preferably 20 μm or more, further preferably 30 μm or more, and particularly preferably 40 μm or more. The upper limit of the thickness of the absorption layer is not particularly limited, but may be, for example, 500 μm. By setting the thickness of the absorption layer within the above range, it becomes easy to suppress the occurrence of dew condensation on the outer peripheral surface of the container.

A print layer may be provided on at least one of the inner surface side and the outer surface side of the absorption layer. For example, characters, patterns, etc. may be printed on the outer surface of the absorption layer. The print layer is provided by a known method according to the material of the outer surface of the absorption layer.

<Fine fibrous cellulose>
The absorption layer contains fibrous cellulose having a fiber width of 1000 nm or less and having a phosphorous acid group or a substituent derived from a phosphorous acid group. The fiber width of the fibrous cellulose can be measured by, for example, observation with an electron microscope.

The average fiber width of the fibrous cellulose is, for example, 1000 nm or less. The average fiber width of the fibrous cellulose is, for example, 2 nm or more and 1000 nm or less, more preferably 2 nm or more and 100 nm or less, further preferably 2 nm or more and 50 nm or less, and 2 nm or more and 10 nm or less. Especially preferable. By setting the average fiber width of the fibrous cellulose to 2 nm or more, it is possible to suppress the dissolution of the fibrous cellulose as a cellulose molecule in water, and to make it easier to exhibit the effects of the fibrous cellulose on improving strength, rigidity and dimensional stability. it can. The fibrous cellulose is, for example, monofibrous cellulose.

The average fiber width of fibrous cellulose is measured, for example, using an electron microscope as follows. First, an aqueous suspension of fibrous cellulose having a concentration of 0.05% by mass or more and 0.1% by mass or less is prepared, and this suspension is cast on a hydrophilized carbon film-coated grid to prepare a sample for TEM observation. And. If it contains wide fibers, an SEM image of the surface cast on the glass may be observed. Next, observation is performed using an electron microscope image at a magnification of 1000 times, 5000 times, 10000 times, or 50,000 times depending on the width of the fiber to be observed. However, the sample, observation conditions and magnification should be adjusted so as to satisfy the following conditions.
(1) A straight line X is drawn at an arbitrary position in the observation image, and 20 or more fibers intersect the straight line X.
(2) A straight line Y that intersects the straight line perpendicularly is drawn in the same image, and 20 or more fibers intersect the straight line Y.
The width of the fiber intersecting the straight line X and the straight line Y is visually read with respect to the observation image satisfying the above conditions. In this way, at least three sets of observation images of surface portions that do not overlap each other are obtained. Next, for each image, the width of the fiber intersecting the straight line X and the straight line Y is read. As a result, at least 20 fibers × 2 × 3 = 120 fibers are read. Then, the average value of the read fiber widths is taken as the average fiber width of the fibrous cellulose.

The fiber length of the fibrous cellulose is not particularly limited, but is preferably 0.1 μm or more and 1000 μm or less, more preferably 0.1 μm or more and 800 μm or less, and further preferably 0.1 μm or more and 600 μm or less. preferable. By setting the fiber length within the above range, destruction of the crystal region of the fibrous cellulose can be suppressed. It is also possible to set the slurry viscosity of the fibrous cellulose in an appropriate range. The fiber length of the fibrous cellulose can be obtained by, for example, image analysis by TEM, SEM, or AFM.

The fibrous cellulose preferably has an I-type crystal structure. Here, the fact that the fibrous cellulose has an I-type crystal structure can be identified in the diffraction profile obtained from a wide-angle X-ray diffraction photograph using CuKα (λ = 1.5418 Å) monochromatic with graphite. Specifically, it can be identified by having typical peaks at two positions, 2θ = 14 ° or more and 17 ° or less and 2θ = 22 ° or more and 23 ° or less.

The ratio of the type I crystal structure to the fine fibrous cellulose is, for example, preferably 30% or more, more preferably 40% or more, and further preferably 50% or more. As a result, even better performance can be expected in terms of heat resistance and low coefficient of linear thermal expansion. The degree of crystallinity is determined by a conventional method from the X-ray diffraction profile measured and the pattern (Seagal et al., Textile Research Journal, Vol. 29, p. 786, 1959).

The axial ratio (fiber length / fiber width) of the fibrous cellulose is not particularly limited, but is preferably 20 or more and 10000 or less, and more preferably 50 or more and 1000 or less. By setting the axial ratio to the above lower limit value or more, it is easy to form an absorption layer containing fine fibrous cellulose. In addition, sufficient viscosity can be easily obtained when the solvent dispersion is produced. By setting the axial ratio to the above upper limit value or less, for example, when fibrous cellulose is treated as an aqueous dispersion, it is preferable in that handling such as dilution becomes easy.

The fibrous cellulose in the present embodiment has, for example, both a crystalline region and a non-crystalline region. In particular, fine fibrous cellulose having both a crystalline region and a non-crystalline region and having a high axial ratio is realized by a method for producing fine fibrous cellulose described later.

The fibrous cellulose in the present embodiment has a phosphorous acid group or a substituent derived from the phosphorous acid group (also simply referred to as a phosphorous acid group). When the absorption layer contains fibrous cellulose having a phosphorous acid group, the water absorption rate of the absorption layer tends to be high, and the occurrence of dew condensation can be suppressed more effectively.

In the present invention, the phosphorous acid group or the substituent derived from the phosphorous acid group is, for example, a substituent represented by the following formula (2).

In equation (2), b is a natural number, m is an arbitrary number, and b × m = 1. α is a hydrogen atom, a saturated-linear hydrocarbon group, a saturated-branched chain hydrocarbon group, a saturated-cyclic hydrocarbon group, an unsaturated-linear hydrocarbon group, an unsaturated-branched chain hydrocarbon group. , An unsaturated-cyclic hydrocarbon group, an aromatic group, or an inducing group thereof. Above all, it is particularly preferable that α is a hydrogen atom. The α in the formula (2) does not include a group derived from the cellulose molecular chain.

Examples of the saturated-linear hydrocarbon group represented by α in the formula (2) include a methyl group, an ethyl group, an n-propyl group, an n-butyl group and the like, but are not particularly limited. Examples of the saturated-branched chain hydrocarbon group include an i-propyl group and a t-butyl group, but are not particularly limited. Examples of the saturated-cyclic hydrocarbon group include, but are not limited to, a cyclopentyl group, a cyclohexyl group and the like. Examples of the unsaturated-linear hydrocarbon group include a vinyl group, an allyl group and the like, but are not particularly limited. Examples of the unsaturated-branched chain hydrocarbon group include an i-propenyl group and a 3-butenyl group, but are not particularly limited. Examples of the unsaturated-cyclic hydrocarbon group include, but are not limited to, a cyclopentenyl group, a cyclohexenyl group and the like. Examples of the aromatic group include a phenyl group and a naphthyl group, but are not particularly limited.

Further, as the inducing group in α, a functional group in which at least one of functional groups such as a carboxy group, a hydroxy group, or an amino group is added or substituted with respect to the main chain or side chain of the above-mentioned various hydrocarbon groups. The group is mentioned, but is not particularly limited. The number of carbon atoms constituting the main chain of R is not particularly limited, but is preferably 20 or less, and more preferably 10 or less. By setting the number of carbon atoms constituting the main chain of R to the above range, the molecular weight of the phosphorous acid group can be set to an appropriate range, the penetration into the fiber raw material is facilitated, and the yield of the fine cellulose fiber can be increased. It can also be increased.

Β ^{b +} in the formula (2) is a monovalent or higher cation composed of an organic substance or an inorganic substance. Examples of monovalent or higher cations composed of organic substances include aliphatic ammonium or aromatic ammonium, and examples of monovalent or higher valent cations composed of inorganic substances include ions of alkali metals such as sodium, potassium, and lithium. Examples thereof include cations of divalent metals such as calcium and magnesium, hydrogen ions, and the like, but the present invention is not particularly limited. These may be applied alone or in combination of two or more. The monovalent or higher cation composed of an organic substance or an inorganic substance is preferably sodium or potassium ion which is hard to yellow when the fiber raw material containing β is heated and is easily industrially used, but is not particularly limited.

The fine fibrous cellulose may have a phosphorous acid group or a group derived from the phosphorous acid group in addition to the phosphorous acid group or the substituent derived from the phosphorous acid group. The phosphoric acid group or the group derived from the phosphoric acid group is, for example, a substituent represented by the following formula (1) or (3). The phosphoric acid group or the group derived from the phosphoric acid group may be a condensed phosphorus oxo acid group as represented by the following formula (3).

In the formula (1), a and b are natural numbers, and m is an arbitrary number (where a = b × m). a number of alpha and alpha 'are O ^- a and the remainder is OR. Here, R is a hydrogen atom, a saturated-linear hydrocarbon group, a saturated-branched chain hydrocarbon group, a saturated-cyclic hydrocarbon group, an unsaturated-linear hydrocarbon group, or an unsaturated-branched chain. A hydrocarbon group, an unsaturated-cyclic hydrocarbon group, an aromatic group, or an inducing group thereof. In addition, α in the formula (1) may be a group derived from a cellulose molecular chain.

In the formula (3), a and b are natural numbers, m is an arbitrary number, and n is a natural number of 2 or more (where a = b × m). ^{α 1, α 2, ···,} a number of alpha ⁿ and alpha 'is O ^- a and the remainder is either R or OR. Here, R is a hydrogen atom, a saturated-linear hydrocarbon group, a saturated-branched chain hydrocarbon group, a saturated-cyclic hydrocarbon group, an unsaturated-linear hydrocarbon group, or an unsaturated-branched chain. A hydrocarbon group, an unsaturated-cyclic hydrocarbon group, an aromatic group, or an inducing group thereof. In addition, α in the formula (3) may be a group derived from a cellulose molecular chain.

The specific examples of each group in the formulas (1) and (3) are the same as the specific examples of each group in the formula (2). Further, the formula (1) and specific examples beta ^{b +} a in (3) are the same as specific examples of beta ^{b +} in equation (2).

The fact that the fine fibrous cellulose has a phosphite group as a substituent means that the infrared absorption spectrum of the dispersion containing the fine fibrous cellulose was measured, and a tautomer of the phosphite group was measured around 1210 cm ^-1. This can be confirmed by observing the P = O-based absorption of a phosphonate group. In addition, the fact that fibrous cellulose has a phosphate group as a substituent can be obtained by measuring the infrared absorption spectrum of the dispersion containing fibrous cellulose and observing the absorption based on the phosphate group in the vicinity of 1230 cm ^-1. You can check. Further, the fact that fibrous cellulose has a phosphite group or a phosphorous acid group as a substituent can be confirmed by a method of confirming a chemical shift by using NMR or a method of combining titration with elemental analysis.

The amount of the phosphorous acid group introduced into the fibrous cellulose is, for example, 0.10 mmol / g or more, more preferably 0.20 mmol / g or more, and 0.50 mmol / g per 1 g (mass) of the fibrous cellulose. It is more preferably / g or more, and particularly preferably 1.00 mmol / g or more. Further, the amount of the phosphorous acid group introduced into the fibrous cellulose is preferably 5.20 mmol / g or less, more preferably 3.65 mmol / g or less per 1 g (mass) of the fibrous cellulose, for example, 3 It is more preferably .50 mmol / g or less, and particularly preferably 3.00 mmol / g or less. By setting the amount of the phosphorous acid group introduced within the above range, it is possible to facilitate the miniaturization of the fiber raw material and enhance the stability of the fibrous cellulose. Further, by setting the amount of the phosphorous acid group introduced within the above range, good characteristics can be exhibited in a sheet containing fibrous cellulose or the like.
Here, the denominator in the unit mmol / g indicates the mass of fibrous cellulose when the counter ion of the phosphite group is a hydrogen ion (H ⁺ ).

The amount of a phosphorous acid group (including a phosphorous acid group) introduced into the fibrous cellulose can be measured by, for example, a neutralization titration method. In the measurement by the neutralization titration method, the introduction amount is measured by determining the change in pH while adding an alkali such as an aqueous sodium hydroxide solution to the obtained slurry containing fibrous cellulose.

FIG. 4 is a graph showing the relationship between the amount of NaOH added dropwise and the pH of the fibrous cellulose-containing slurry having a phosphoric acid group. The amount of the phosphorus oxo acid group introduced into the fibrous cellulose is measured, for example, as follows.
First, the slurry containing fibrous cellulose is treated with a strongly acidic ion exchange resin. If necessary, the same defibration treatment as the defibration treatment step described later may be performed on the measurement target before the treatment with the strongly acidic ion exchange resin.
Next, the change in pH is observed while adding an aqueous sodium hydroxide solution, and a titration curve as shown in the upper part of FIG. 4 is obtained. The titration curve shown in the upper part of FIG. 4 plots the measured pH with respect to the amount of alkali added, and the titration curve shown in the lower part of FIG. 4 plots the pH with respect to the amount of alkali added. The increment (differential value) (1 / mmol) is plotted. In this neutralization titration, it is confirmed that there are two points where the increment (differential value of pH with respect to the amount of alkali dropped) becomes maximum in the curve plotting the measured pH with respect to the amount of alkali added. Of these, the maximum point of the increment obtained first when alkali is added is called the first end point, and the maximum point of the increment obtained next is called the second end point. The amount of alkali required from the start of titration to the first end point is equal to the amount of first dissociating acid of the fibrous cellulose contained in the slurry used for titration, and the amount of alkali required from the first end point to the second end point. The amount is equal to the amount of the second dissociating acid of the fibrous cellulose contained in the slurry used for the titration, and the amount of alkali required from the start to the second end point of the titration is the fibrous cellulose contained in the slurry used for the titration. Is equal to the total amount of dissociated acid. Then, the value obtained by dividing the amount of alkali required from the start of titration to the first end point by the solid content (g) in the slurry to be titrated is the amount of phosphorus oxo acid group introduced (mmol / g). The amount of phosphorus oxo acid group introduced (or the amount of phosphorus oxo acid group) simply means the amount of the first dissociated acid.
In FIG. 4, the region from the start of titration to the first end point is referred to as a first region, and the region from the first end point to the second end point is referred to as a second region. For example, when the phosphoric acid group is a phosphoric acid group and the phosphoric acid group causes condensation, the amount of weakly acidic groups in the phosphoric acid group (also referred to as the second dissociated acid amount in the present specification) is apparently It decreases, and the amount of alkali required for the second region is smaller than the amount of alkali required for the first region. On the other hand, the amount of strongly acidic groups in the phosphorus oxo acid group (also referred to as the first dissociated acid amount in the present specification) is the same as the amount of phosphorus atoms regardless of the presence or absence of condensation. Further, when the phosphorous acid group is a phosphorous acid group, the weakly acidic group does not exist in the phosphorous acid group, so that the amount of alkali required for the second region is reduced or the amount of alkali required for the second region is reduced. May be zero. In this case, the titration curve has one point where the pH increment is maximized.

Since the denominator of the above-mentioned phosphorus oxo acid group introduction amount (mmol / g) indicates the mass of the acid-type fibrous cellulose, the phosphorus oxo acid group amount of the acid-type fibrous cellulose (hereinafter referred to as the phosphorus oxo acid group amount). (Called (acid type))). On the other hand, when the counterion of the phosphorus oxo acid group is replaced with an arbitrary cation C so as to have a charge equivalent, the denominator is converted to the mass of fibrous cellulose when the cation C is a counterion. This makes it possible to determine the amount of phosphorus oxo acid groups (hereinafter, the amount of phosphorus oxo acid groups (C type)) possessed by the fibrous cellulose in which the cation C is a counter ion.
That is, it is calculated by the following formula.
Phosphoric acid group amount (C type) = Phosphoric acid group amount (acid type) / {1+ (W-1) x A / 1000}
A [mmol / g]: Total amount of anion derived from phosphoric acid group of fibrous cellulose (total amount of dissociated acid of phosphoric acid group)
W: Formula amount per valence of cation C (for example, Na is 23, Al is 9)

In the measurement of the amount of phosphorus oxo acid groups by the titration method, if the amount of one drop of the sodium hydroxide aqueous solution is too large or the titration interval is too short, the amount of phosphorus oxo acid groups will be lower than the original value. It may not be obtained. As an appropriate dropping amount and titration interval, for example, it is desirable to titrate 10 to 50 μL of a 0.1 N sodium hydroxide aqueous solution every 5 to 30 seconds. Further, in order to eliminate the influence of carbon dioxide dissolved in the fibrous cellulose-containing slurry, for example, it is desirable to measure while blowing an inert gas such as nitrogen gas into the slurry from 15 minutes before the start of titration to the end of titration.

In addition, which of the phosphite, the phosphoric acid, and the condensed phosphoric acid is the phosphoric acid detected when the phosphoric acid group, the condensed phosphoric acid group, or both is contained in addition to the phosphite group? As a method for distinguishing between, for example, a method of performing a treatment for cutting the condensed structure such as acid hydrolysis and then performing the above-mentioned titration operation, or a treatment for converting a phosphite group into a phosphate group such as an oxidation treatment. Examples thereof include a method of performing the above-mentioned titration operation after the operation.

<Manufacturing process of fine fibrous cellulose>
<Fiber raw material>
Fine fibrous cellulose is produced from a fiber raw material containing cellulose. The fiber raw material containing cellulose is not particularly limited, but pulp is preferably used because it is easily available and inexpensive. Examples of pulp include wood pulp, non-wood pulp, and deinked pulp. The wood pulp is not particularly limited, but is, for example, broadleaf kraft pulp (LBKP), coniferous kraft pulp (NBKP), sulfite pulp (SP), dissolved pulp (DP), soda pulp (AP), and unbleached kraft pulp (UKP). ) And chemical pulp such as oxygen bleached kraft pulp (OKP), semi-chemical pulp such as semi-chemical pulp (SCP) and chemiground wood pulp (CGP), crushed wood pulp (GP) and thermomechanical pulp (TMP, BCTMP), etc. Examples include mechanical pulp. The non-wood pulp is not particularly limited, and examples thereof include cotton pulp such as cotton linter and cotton lint, and non-wood pulp such as hemp, straw and bagasse. The deinking pulp is not particularly limited, and examples thereof include deinking pulp made from used paper. As the pulp of the present embodiment, one of the above types may be used alone, or two or more types may be mixed and used.
Among the above pulps, for example, wood pulp and deinked pulp are preferable from the viewpoint of availability. Further, among wood pulps, from the viewpoint of high cellulose ratio and high yield of fine fibrous cellulose during defibration treatment, long fiber fine fibrous cellulose having a small decomposition of cellulose in pulp and a large axial ratio can be obtained. From the viewpoint, for example, chemical pulp is more preferable, and kraft pulp and sulfite pulp are further preferable.

As the fiber raw material containing cellulose, for example, cellulose contained in ascidians and bacterial cellulose produced by acetobacter can be used. Further, instead of the fiber raw material containing cellulose, a fiber formed by a linear nitrogen-containing polysaccharide polymer such as chitin or chitosan can be used.

<Phosphorous acid group introduction process>
In the phosphite group introduction step, at least one compound (hereinafter, also referred to as “compound A”) selected from compounds capable of introducing a phosphorous acid group by reacting with a hydroxyl group of a fiber raw material containing cellulose is introduced. , A step of acting on a fiber raw material containing cellulose. By this step, a phosphite group-introduced fiber can be obtained.

In the phosphorous acid group introduction step according to the present embodiment, the reaction between the fiber raw material containing cellulose and Compound A is carried out in the presence of at least one selected from urea and its derivatives (hereinafter, also referred to as “Compound B”). You may go. On the other hand, the reaction of the fiber raw material containing cellulose with the compound A may be carried out in the absence of the compound B.

As an example of the method of allowing the compound A to act on the fiber raw material in the coexistence with the compound B, a method of mixing the compound A and the compound B with the fiber raw material in a dry state, a wet state or a slurry state can be mentioned. Of these, since the reaction uniformity is high, it is preferable to use a fiber raw material in a dry state or a wet state, and it is particularly preferable to use a fiber raw material in a dry state. The form of the fiber raw material is not particularly limited, but is preferably cotton-like or thin sheet-like, for example. Examples of the compound A and the compound B include a method of adding the compound A and the compound B to the fiber raw material in the form of a powder or a solution dissolved in a solvent, or in a state of being heated to a melting point or higher and melted. Of these, since the reaction uniformity is high, it is preferable to add the solution in the form of a solution dissolved in a solvent, particularly in the state of an aqueous solution. Further, compound A and compound B may be added to the fiber raw material at the same time, separately, or as a mixture. The method for adding the compound A and the compound B is not particularly limited, but when the compound A and the compound B are in the form of a solution, the fiber raw material may be immersed in the solution to absorb the liquid and then taken out, or the fiber raw material may be taken out. The solution may be dropped into the water. Further, the required amounts of Compound A and Compound B may be added to the fiber raw material, or after the excess amounts of Compound A and Compound B are added to the fiber raw material, respectively, the surplus Compound A and Compound B are added by pressing or filtering. It may be removed.

The compound A used in this embodiment is at least one selected from a compound having a phosphorous acid group and a salt thereof. Examples of the compound having a phosphorous acid group include phosphorous acid, and examples of phosphorous acid include 99% phosphorous acid (phosphonic acid). Examples of the salt of the compound having a phosphorous acid group include a lithium salt, a sodium salt, a potassium salt and an ammonium salt of phosphorous acid, and these can have various neutralization degrees. Of these, phosphorous acid and phosphorous acid are highly efficient in introducing phosphorous acid groups, are more likely to improve defibration efficiency in the defibration step described later, are low in cost, and are easy to apply industrially. Sodium salts of acids, potassium salts of phosphorous acid, or ammonium salts of phosphorous acid are preferably used.

The amount of compound A added to the fiber raw material is not particularly limited, but for example, when the amount of compound A added is converted to the phosphorus atomic weight, the amount of phosphorus atom added to the fiber raw material (absolute dry mass) is 0.5% by mass or more. It is preferably 100% by mass or less, more preferably 1% by mass or more and 50% by mass or less, and further preferably 2% by mass or more and 30% by mass or less. By setting the amount of phosphorus atoms added to the fiber raw material within the above range, the yield of fine fibrous cellulose can be further improved. On the other hand, by setting the addition amount of phosphorus atoms to the fiber raw material to be equal to or less than the above upper limit value, the effect of improving the yield and the cost can be balanced.

Compound B used in this embodiment is at least one selected from urea and its derivatives as described above. Examples of compound B include urea, biuret, 1-phenylurea, 1-benzylurea, 1-methylurea, 1-ethylurea and the like. From the viewpoint of improving the uniformity of the reaction, compound B is preferably used as an aqueous solution. Further, from the viewpoint of further improving the uniformity of the reaction, it is preferable to use an aqueous solution in which both compound A and compound B are dissolved.

The amount of compound B added to the fiber raw material (absolute dry mass) is not particularly limited, but is preferably 1% by mass or more and 500% by mass or less, and more preferably 10% by mass or more and 400% by mass or less. It is more preferably 100% by mass or more and 350% by mass or less.

In the reaction between the fiber raw material containing cellulose and compound A, for example, amides or amines may be contained in the reaction system in addition to compound B. Examples of amides include formamide, dimethylformamide, acetamide, dimethylacetamide and the like. Examples of amines include methylamine, ethylamine, trimethylamine, triethylamine, monoethanolamine, diethanolamine, triethanolamine, pyridine, ethylenediamine, hexamethylenediamine and the like. Among these, triethylamine is known to act as a good reaction catalyst.

In the phosphorous acid group introduction step, it is preferable to add or mix the compound A or the like to the fiber raw material and then heat-treat the fiber raw material. As the heat treatment temperature, it is preferable to select a temperature at which the phosphite group can be efficiently introduced while suppressing the thermal decomposition and hydrolysis reaction of the fiber. The heat treatment temperature is, for example, preferably 50 ° C. or higher and 300 ° C. or lower, more preferably 100 ° C. or higher and 250 ° C. or lower, and further preferably 130 ° C. or higher and 200 ° C. or lower. In addition, equipment having various heat media can be used for the heat treatment, for example, a stirring drying device, a rotary drying device, a disk drying device, a roll type heating device, a plate type heating device, a fluidized layer drying device, and an air stream. A drying device, a vacuum drying device, an infrared heating device, a far infrared heating device, a microwave heating device, and a high frequency drying device can be used.

In the heat treatment according to the present embodiment, for example, a method of adding compound A to a thin sheet-shaped fiber raw material by a method such as impregnation and then heating, or a method of heating while kneading or stirring the fiber raw material and compound A with a kneader or the like. Can be adopted. This makes it possible to suppress uneven concentration of compound A in the fiber raw material and more uniformly introduce the phosphorous acid group onto the surface of the cellulose fiber contained in the fiber raw material. This is because when the water molecules move to the surface of the fiber raw material due to drying, the dissolved compound A is attracted to the water molecules by the surface tension and also moves to the surface of the fiber raw material (that is, the concentration unevenness of the compound A is caused. It is considered that this is due to the fact that it can be suppressed.

Further, the heating device used for the heat treatment always keeps the water content retained by the slurry and the water content generated by the dehydration condensation (phosphate esterification) reaction between the compound A and the hydroxyl group contained in the cellulose or the like in the fiber raw material. It is preferable that the device can be discharged to the outside of the device system. Examples of such a heating device include a ventilation type oven and the like. By constantly discharging the water in the apparatus system, in addition to being able to suppress the hydrolysis reaction of the phosphate ester bond, which is the reverse reaction of phosphate esterification, it is also possible to suppress the acid hydrolysis of the sugar chain in the fiber. it can. Therefore, it is possible to obtain fine fibrous cellulose having a high axial ratio.

The heat treatment time is preferably 1 second or more and 300 minutes or less, more preferably 1 second or more and 1000 seconds or less, and 10 seconds or more and 800 seconds or less after the water is substantially removed from the fiber raw material. Is more preferable. In the present embodiment, the amount of the phosphorous acid group introduced can be within a preferable range by setting the heating temperature and the heating time within an appropriate range.

The phosphorous acid group introduction step may be performed at least once, but may be repeated twice or more. By performing the phosphorous acid group introduction step two or more times, many phosphorous acid groups can be introduced into the fiber raw material.

The amount of the phosphorous acid group introduced into the fiber raw material is, for example, 0.10 mmol / g or more, more preferably 0.20 mmol / g or more, and 0.50 mmol / g per 1 g (mass) of fine fibrous cellulose. It is more preferably / g or more, and particularly preferably 1.00 mmol / g or more. Further, the amount of the phosphorous acid group introduced into the fiber raw material is preferably 5.20 mmol / g or less, more preferably 3.65 mmol / g or less per 1 g (mass) of fine fibrous cellulose, for example, 3 It is more preferably 0.00 mmol / g or less. By setting the amount of the phosphorous acid group introduced within the above range, it is possible to facilitate the miniaturization of the fiber raw material and enhance the stability of the fine fibrous cellulose.

<Washing process>
In the method for producing fine fibrous cellulose in the present embodiment, a washing step can be performed on the phosphite group-introduced fiber as needed. The cleaning step is performed, for example, by cleaning the phosphite group-introduced fibers with water or an organic solvent. Further, the cleaning step may be performed after each step described later, and the number of cleanings performed in each cleaning step is not particularly limited.

<Alkaline treatment process>
When producing fine fibrous cellulose, an alkali treatment may be performed on the fiber raw material between the phosphite group introduction step and the defibration treatment step described later. The alkaline treatment method is not particularly limited, and examples thereof include a method of immersing the phosphorous acid group-introduced fiber in an alkaline solution.

The alkaline compound contained in the alkaline solution is not particularly limited, and may be an inorganic alkaline compound or an organic alkaline compound. In the present embodiment, for example, sodium hydroxide or potassium hydroxide is preferably used as the alkaline compound because of its high versatility. Further, the solvent contained in the alkaline solution may be either water or an organic solvent. Among them, the solvent contained in the alkaline solution is preferably a polar solvent containing water or a polar organic solvent exemplified by alcohol, and more preferably an aqueous solvent containing at least water. As the alkaline solution, for example, an aqueous solution of sodium hydroxide or an aqueous solution of potassium hydroxide is preferable because of its high versatility.

The temperature of the alkaline solution in the alkaline treatment step is not particularly limited, but is preferably 5 ° C. or higher and 80 ° C. or lower, and more preferably 10 ° C. or higher and 60 ° C. or lower. The immersion time of the phosphorous acid group-introduced fiber in the alkaline solution in the alkali treatment step is not particularly limited, but is preferably 5 minutes or more and 30 minutes or less, and more preferably 10 minutes or more and 20 minutes or less. The amount of the alkaline solution used in the alkaline treatment is not particularly limited, but is preferably 100% by mass or more and 100,000% by mass or less, and 1000% by mass or more and 10000% by mass or less, based on the absolute dry mass of the phosphorous acid group-introduced fiber. The following is more preferable.

In order to reduce the amount of the alkaline solution used in the alkali treatment step, the phosphite group-introduced fiber may be washed with water or an organic solvent after the phosphite group introduction step and before the alkali treatment step. After the alkali treatment step and before the defibration treatment step, it is preferable to wash the alkali-treated phosphorous acid group-introduced fiber with water or an organic solvent from the viewpoint of improving handleability.

<Acid treatment process>
When producing fine fibrous cellulose, the fiber raw material may be subjected to acid treatment between the step of introducing a phosphorous acid group and the defibration treatment step described later. For example, the phosphorous acid group introduction step, the acid treatment, the alkali treatment, and the defibration treatment may be performed in this order.

The method of the acid treatment is not particularly limited, and examples thereof include a method of immersing the fiber raw material in an acidic liquid containing an acid. The concentration of the acidic liquid used is not particularly limited, but is preferably 10% by mass or less, and more preferably 5% by mass or less, for example. The pH of the acidic solution used is not particularly limited, but is preferably 0 or more and 4 or less, and more preferably 1 or more and 3 or less. As the acid contained in the acidic solution, for example, an inorganic acid, a sulfonic acid, a carboxylic acid or the like can be used. Examples of the inorganic acid include sulfuric acid, nitric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, hypochlorous acid, chloric acid, chloric acid, perchloric acid, phosphoric acid, boric acid and the like. Examples of the sulfonic acid include methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, trifluoromethanesulfonic acid and the like. Examples of the carboxylic acid include formic acid, acetic acid, citric acid, gluconic acid, lactic acid, oxalic acid, tartaric acid and the like. Among these, it is particularly preferable to use hydrochloric acid or sulfuric acid.

The temperature of the acid solution in the acid treatment is not particularly limited, but is preferably 5 ° C. or higher and 100 ° C. or lower, and more preferably 20 ° C. or higher and 90 ° C. or lower. The immersion time in the acid solution in the acid treatment is not particularly limited, but is preferably 5 minutes or more and 120 minutes or less, and more preferably 10 minutes or more and 60 minutes or less. The amount of the acid solution used in the acid treatment is not particularly limited, but is preferably 100% by mass or more and 100,000% by mass or less, and 1,000% by mass or more and 10,000% by mass or less, for example, with respect to the absolute dry mass of the fiber raw material. Is more preferable.

<Fiber processing>
Fine fibrous cellulose can be obtained by defibrating the phosphite-introduced fiber in the defibration treatment step. In the defibration treatment step, for example, a defibration treatment apparatus can be used. The defibrating apparatus is not particularly limited, but for example, a high-speed defibrator, a grinder (stone mill type crusher), a high-pressure homogenizer or an ultra-high pressure homogenizer, a high-pressure collision type crusher, a ball mill, a bead mill, a disc type refiner, a conical refiner, and a twin shaft. A kneader, a vibration mill, a homomixer under high speed rotation, an ultrasonic disperser, or a beater can be used. Among the above-mentioned defibration processing devices, it is more preferable to use a high-speed defibrator, a high-pressure homogenizer, and an ultra-high-pressure homogenizer, which are less affected by crushed media and less likely to cause contamination.

In the defibration treatment step, for example, it is preferable to dilute the phosphorous acid group-introduced fiber with a dispersion medium to form a slurry. As the dispersion medium, one or more selected from water and an organic solvent such as a polar organic solvent can be used. The polar organic solvent is not particularly limited, but for example, alcohols, polyhydric alcohols, ketones, ethers, esters, aproton polar solvents and the like are preferable. Examples of alcohols include methanol, ethanol, isopropanol, n-butanol, isobutyl alcohol and the like. Examples of polyhydric alcohols include ethylene glycol, propylene glycol, glycerin and the like. Examples of ketones include acetone, methyl ethyl ketone (MEK) and the like. Examples of ethers include diethyl ether, tetrahydrofuran, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono n-butyl ether, propylene glycol monomethyl ether and the like. Examples of the esters include ethyl acetate, butyl acetate and the like. Examples of the aprotic polar solvent include dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMAc), N-methyl-2-pyrrolidinone (NMP) and the like.

The solid content concentration of the fine fibrous cellulose during the defibration treatment can be appropriately set. Further, the slurry obtained by dispersing the phosphorous acid group-introduced fiber in a dispersion medium may contain a solid content other than the phosphorous acid group-introduced fiber such as urea having a hydrogen bond property.

<Manufacturing process of absorption layer>
The step of producing the absorption layer preferably includes a step of mixing a dispersion liquid of fine fibrous cellulose having a phosphorous acid group or a substituent derived from the phosphorous acid group with a resin solution to obtain a mixed liquid. The types of the dispersion mediums of the fine fibrous cellulose dispersion and the resin solution are not particularly limited, and examples thereof include water, an organic solvent, and a mixture of water and an organic solvent. Above all, the solvent is preferably water.

The content of the fine fibrous cellulose in the dispersion liquid of the fine fibrous cellulose is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, based on the total mass of the dispersion liquid. preferable. The content of the fine fibrous cellulose is preferably 20% by mass or less, more preferably 15% by mass or less, based on the total mass of the dispersion.

The resin concentration in the resin solution is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, based on the total mass of the resin solution. The resin concentration is preferably 20% by mass or less, more preferably 15% by mass or less, based on the total mass of the resin solution.

When forming a sheet to be an absorption layer from a mixed solution of fine fibrous cellulose and a resin, a coating step of applying the mixed solution onto a base material or a papermaking step of making a papermaking of the mixed solution is included.

<< Coating process >>
In the coating step, for example, a mixed solution (slurry) is applied onto a base material, and the sheet formed by drying the mixed solution (slurry) is peeled off from the base material to obtain a sheet. Further, by using a coating device and a long base material, sheets can be continuously produced.

The material of the base material used in the coating process is not particularly limited, but a material having high wettability to the slurry may be able to suppress shrinkage of the sheet during drying, but a sheet formed after drying is easy. It is preferable to select one that can be peeled off. Of these, a resin film or plate or a metal film or plate is preferable, but is not particularly limited. For example, resin films and plates such as acrylic, polyethylene terephthalate, vinyl chloride, polystyrene, and polyvinylidene chloride, metal films and plates of aluminum, zinc, copper, and iron plates, and those whose surfaces are oxidized, stainless films. And boards, brass films and boards can be used.

In the coating process, if the viscosity of the slurry is low and it develops on the base material, a dammed frame is fixed on the base material in order to obtain a sheet with a predetermined thickness and basis weight. You may. The frame for damming is not particularly limited, but it is preferable to select, for example, a frame in which the end portion of the sheet that adheres after drying can be easily peeled off. From this point of view, a resin plate or a metal plate molded is more preferable. In the present embodiment, for example, a resin plate such as an acrylic plate, a polyethylene terephthalate plate, a vinyl chloride plate, a polystyrene plate, or a polyvinylidene chloride plate, a metal plate such as an aluminum plate, a zinc plate, a copper plate, or an iron plate, and their surfaces are used. Oxidized ones, stainless steel plates, brass plates and the like can be molded.

The coating machine for coating the slurry on the base material is not particularly limited, and for example, a roll coater, a gravure coater, a die coater, a curtain coater, an air doctor coater, or the like can be used. A die coater, a curtain coater, and a spray coater are particularly preferable because the thickness of the sheet can be made more uniform.

The slurry temperature and the atmospheric temperature when the slurry is applied to the substrate are not particularly limited, but are preferably, for example, 5 ° C. or higher and 80 ° C. or lower, more preferably 10 ° C. or higher and 60 ° C. or lower, and 15 ° C. It is more preferably 50 ° C. or lower, and particularly preferably 20 ° C. or higher and 40 ° C. or lower. When the coating temperature is equal to or higher than the above lower limit, the slurry can be coated more easily. When the coating temperature is not more than the above upper limit value, volatilization of the dispersion medium during coating can be suppressed.

In the coating process, the slurry is based so that the finished basis weight of the sheet is preferably 10 g / m ² or more and 200 g / m ² or less, and more preferably 20 g / m ² or more and 150 g / m ² or less. It is preferable to coat the material. By coating so that the basis weight is within the above range, a sheet having excellent strength can be obtained.

As described above, the coating step includes a step of drying the slurry coated on the substrate. The step of drying the slurry is not particularly limited, but is performed by, for example, a non-contact drying method, a method of drying while restraining the sheet, or a combination thereof. The non-contact drying method is not particularly limited, and for example, a method of heating and drying with hot air, infrared rays, far infrared rays or near infrared rays (heat drying method), or a method of vacuum drying (vacuum drying method) is applied. can do. Although the heat drying method and the vacuum drying method may be combined, the heat drying method is usually applied. Drying with infrared rays, far infrared rays or near infrared rays is not particularly limited, but can be performed by using, for example, an infrared device, a far infrared device or a near infrared device. The heating temperature in the heat drying method is not particularly limited, but is preferably 20 ° C. or higher and 150 ° C. or lower, and more preferably 25 ° C. or higher and 105 ° C. or lower. When the heating temperature is at least the above lower limit value, the dispersion medium can be rapidly volatilized. Further, when the heating temperature is not more than the above upper limit value, it is possible to suppress the cost required for heating and suppress the discoloration of the fibrous cellulose due to heat.

<< Papermaking process >>
The papermaking process is performed by making a mixed solution (slurry) with a paper machine. The paper machine used in the paper making process is not particularly limited, and examples thereof include continuous paper machines such as a long net type, a circular net type, and an inclined type, and a multi-layer paper making machine combining these. In the papermaking process, a known papermaking method such as hand-making may be adopted.

The papermaking process is performed by filtering and dehydrating the slurry with a wire to obtain a wet paper sheet, and then pressing and drying the sheet. The filter cloth used for filtering and dehydrating the slurry is not particularly limited, but it is more preferable that, for example, fibrous cellulose does not pass through and the filtration rate does not become too slow. Such a filter cloth is not particularly limited, but for example, a sheet made of an organic polymer, a woven fabric, or a porous membrane is preferable. The organic polymer is not particularly limited, but non-cellulosic organic polymers such as polyethylene terephthalate, polyethylene, polypropylene, and polytetrafluoroethylene (PTFE) are preferable. In the present embodiment, for example, a porous membrane of polytetrafluoroethylene having a pore size of 0.1 μm or more and 20 μm or less, polyethylene terephthalate having a pore size of 0.1 μm or more and 20 μm or less, a polyethylene woven fabric, or the like can be mentioned.

In the sheeting process, a method of producing a sheet from a slurry is, for example, a watering section in which the slurry is discharged onto the upper surface of an endless belt and a dispersion medium is squeezed from the discharged slurry to generate a web, and the web is dried. This can be done using a manufacturing apparatus equipped with a drying section to produce the sheet. An endless belt is arranged from the watering section to the drying section, and the web generated in the watering section is conveyed to the drying section while being placed on the endless belt.

The dehydration method used in the papermaking process is not particularly limited, and examples thereof include a dehydration method usually used in the production of paper. Among these, a method of dehydrating with a long net, a circular net, an inclined wire or the like and then further dehydrating with a roll press is preferable. The drying method used in the papermaking process is not particularly limited, and examples thereof include a method used in the production of paper. Among these, a drying method using a cylinder dryer, a Yankee dryer, hot air drying, a near infrared heater, an infrared heater, or the like is more preferable.

(Adhesive layer)
The absorption layer 30 may be laminated so as to be in direct contact with the base material layer 20, but another layer may be provided between the absorption layer 30 and the base material layer 20. In this case, as shown in FIG. 5, it is preferable that the adhesive layer 25 is provided between the absorption layer 30 and the base material layer 20. That is, the absorption layer 30 may be laminated on the base material layer 20 via the adhesive layer 25. In FIG. 5, since the layer configurations of the base material layer 20, the adhesive layer 25, and the absorption layer 30 are drawn so as to be easy to understand, the thickness and the ratio of the thickness of each layer are not necessarily the same as the actual container configuration. Absent.

As an adhesive constituting the adhesive layer, for example, an acrylic resin can be mentioned. Examples of the adhesive other than the acrylic resin include vinyl chloride resin, (meth) acrylic acid ester resin, styrene / acrylic acid ester copolymer resin, vinyl acetate resin, vinyl acetate / (meth) acrylic. Acid ester copolymer resin, urethane resin, silicone resin, epoxy resin, ethylene / vinyl acetate copolymer resin, polyester resin, polyvinyl alcohol resin, ethylene vinyl alcohol copolymer resin, SBR, NBR, etc. Examples include rubber-based emulsions.

The thickness of the adhesive layer is preferably 0.1 μm or more, more preferably 1 μm or more, and further preferably 2 μm or more. The thickness of the adhesive layer is preferably 50 μm or less, more preferably 20 μm or less, and even more preferably 10 μm or less. Here, the thickness of the adhesive layer is a value measured by cutting out a cross section of the body member of the container with an ultramicrotome UC-7 (manufactured by JEOL Ltd.) and observing the cross section with an electron microscope, a magnifying glass, or visually. ..

(Transparent layer)
A transmission layer 40 may be further provided on the outer surface side of the absorption layer 30. As shown in FIG. 6, the transmission layer 40 is arranged on the outer surface side of the absorption layer 30. In the container 100, the base material layer 20, the absorption layer 30, and the transmission layer 40 may be laminated in this order from the inner surface side, and another layer such as an adhesive layer is provided between the layers. May be good. That is, in the container 100, the base material layer 20, the adhesive layer, the absorption layer 30, the adhesive layer and the transmission layer 40 may be laminated in this order from the inner surface side. In FIG. 6, since the layer configurations of the base material layer 20, the absorption layer 30, and the transmission layer 40 are drawn so as to be easy to understand, the thickness and the ratio of the thickness of each layer are not necessarily the same as the actual container configuration. Absent.

The permeable layer is a layer capable of allowing moisture to permeate. Since the permeable layer is capable of allowing water to permeate, the water absorption rate in the absorbing layer is not reduced. On top of that, the permeable layer functions to enhance the design of the container and enhance the usability of the container. For example, when a layer containing pulp is used as the permeable layer, the sticky feeling on the surface of the container can be suppressed, and the refreshing feeling of the handle portion of the user can be enhanced.

The permeable layer is preferably a layer containing at least one selected from pulp and resin. Above all, the permeable layer is more preferably a layer containing pulp, and for example, the permeable layer is preferably paper. When the permeable layer is made of resin or the like, pores may be provided in the sheet to be the permeable layer in order to enhance the moisture permeability of the permeable layer. As described above, a transparent layer having pores is also preferably used.

The thickness of the permeable layer is not particularly limited, but for example, it is preferably 10 μm or more, more preferably 50 μm or more, further preferably 100 μm or more, and the thickness of the permeable layer is. It is preferably 5000 μm or less.

A print layer may be provided on at least one of the inner surface side and the outer surface side of the transparent layer. For example, characters, patterns, etc. may be printed on the outer surface of the transparent layer. The print layer is provided by a known method according to the material of the outer surface of the transparent layer.

(Manufacturing method of container)
The container manufacturing step preferably includes any of the following steps (a) or (b).
(A) Step: A laminated sheet including a base material layer and an absorbing layer is obtained, and the laminated sheet is molded into a container shape.
(B) Step: After the base material layer is formed into a container shape, an absorption layer is provided on the outer peripheral surface of the base material layer.
In the container manufacturing process, as described above, a sheet to be an absorption layer may be prepared in advance and then overlapped with the base material layer, and a slurry for forming an absorption layer is applied on the base material layer. , The absorption layer may be formed by drying. When the slurry for forming the absorption layer is applied onto the base material layer and dried, the same conditions as in the above-mentioned << coating step >> may be adopted.

Before forming the laminated sheet into a container shape in the step (a) and before forming the base material layer into a container shape in the step (b), each sheet member is cut into a desired shape. When molding into a container shape, for example, it can be molded using a known molding machine, and for example, a cup molding machine or the like can be used.

When obtaining a laminated sheet in the step (a) or when providing the absorption layer on the outer peripheral surface of the base material layer in the step (b), for example, an adhesive is applied to the absorption layer, and this coated surface is used as the base material layer. Can be bonded to the outer peripheral surface side of the. In this case, a UV curable adhesive may be used as the adhesive. When a UV curable adhesive is used, it is possible to firmly bond the absorption layer and the base material layer by irradiating ultraviolet rays from the absorption layer side after attaching the absorption layer to the base material layer via the adhesive layer. it can.

Further, when an adhesive is not used when obtaining a laminated sheet in the step (a) or when providing the absorption layer on the outer peripheral surface of the base material layer in the step (b), the base material is made after immersing the absorption layer in water. The absorbent layer may be bonded to the outer peripheral surface side of the layer, or the slurry forming the absorbent layer may be applied on the outer peripheral surface of the base material layer and dried to form the absorbent layer.

The present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to the following examples.

[Example 1]
[Preparation of subphosphorylated pulp]
As raw material pulp, softwood kraft pulp made by Oji Paper (solid content 93% by mass, basis weight 245 g / m ² sheet, dissociated and measured according to JIS P 8121, Canadian standard drainage degree (CSF) is 700 ml) It was used.

The raw material pulp was subjected to phosphorus oxo oxidation treatment as follows. First, a mixed aqueous solution of phosphorous acid (phosphonic acid) and urea is added to 100 parts by mass (absolute dry mass) of the raw material pulp to add 33 parts by mass of phosphorous acid (phosphonic acid), 120 parts by mass of urea, and 150 parts of water. The amount was adjusted to be parts by mass, and a chemical-impregnated pulp was obtained. Next, the obtained chemical-impregnated pulp was heated in a hot air dryer at 165 ° C. for 250 seconds to introduce a phosphorous acid group into the cellulose in the pulp to obtain a phosphorylated pulp.

Then, the obtained subphosphorylated pulp was washed. In the washing treatment, the pulp dispersion obtained by pouring 10 L of ion-exchanged water into 100 g (absolute dry mass) of subphosphorylated pulp is stirred so that the pulp is uniformly dispersed, and then filtration and dehydration are repeated. Was done by. When the electrical conductivity of the filtrate became 100 μS / cm or less, the washing end point was set.

Next, the washed subphosphorylated pulp was neutralized as follows. First, the washed subphosphorylated pulp is diluted with 10 L of ion-exchanged water, and then a 1N aqueous sodium hydroxide solution is added little by little with stirring to obtain a subphosphorylated pulp slurry having a pH of 12 or more and 13 or less. Obtained. Next, the subphosphorylated pulp slurry was dehydrated to obtain a neutralized subphosphorylated pulp. Next, the subphosphorylated pulp after the neutralization treatment was subjected to the above washing treatment.

The infrared absorption spectrum of the obtained subphosphorylated pulp was measured using FT-IR. As a result, absorption based on P = O of the phosphonic acid group, which is a tautomer of the phosphite group, was observed around 1210 cm ^-1 , and the phosphite group (phosphonic acid group) was added to the pulp. Was confirmed. Further, when the obtained subphosphorylated pulp was tested and analyzed by an X-ray diffractometer, two positions were found: 2θ = 14 ° or more and 17 ° or less and 2θ = 22 ° or more and 23 ° or less. A typical peak was confirmed in, and it was confirmed that it had cellulose type I crystals. Regarding the obtained phosphorous acid pulp, the amount of phosphorous acid group (first dissociated acid amount) measured by the measurement method described in [Measurement of phosphorous acid group amount] described later was 1.51 mmol / g. It was. The total amount of dissociated acid was 1.54 mmol / g.

[Defibering process]
Ion-exchanged water was added to the obtained subphosphorylated pulp to prepare a slurry having a solid content concentration of 2% by mass. This slurry was treated twice with a wet atomizer (Starburst, manufactured by Sugino Machine Limited) at a pressure of 200 MPa to obtain a fine fibrous cellulose dispersion A containing fine fibrous cellulose. By X-ray diffraction, it was confirmed that this fine fibrous cellulose maintained the cellulose type I crystal. Moreover, when the fiber width of the fine fibrous cellulose was measured using a transmission electron microscope, it was 3 to 5 nm.

[Dissolution of polyvinyl alcohol]
Polyvinyl alcohol (manufactured by Kuraray Co., Ltd., Poval 105, degree of polymerization: 500, degree of saponification: 98 to 99 mol%) was added to ion-exchanged water so as to have a concentration of 20% by mass, and the mixture was stirred at 95 ° C. for 1 hour to dissolve it. .. An aqueous polyvinyl alcohol solution was obtained by the above procedure.

[Preparation of fine fibrous cellulose-containing sheet]
The fine fibrous cellulose dispersion A and the above polyvinyl alcohol aqueous solution were each diluted with ion-exchanged water so that the solid content concentration was 0.6% by mass. Next, 10 parts by mass of the diluted fine fibrous cellulose dispersion was mixed with 90 parts by mass of the diluted polyvinyl alcohol aqueous solution to obtain a mixed solution A. Further, the mixed solution A was weighed so that the finished basis weight of the sheet was 60 g / m ² , and developed on a commercially available transparent acrylic plate. A frame for damming (inner dimensions 180 mm × 180 mm, height 50 mm) was arranged on the acrylic plate so as to have a predetermined basis weight. Then, it was dried in a dryer at 70 ° C. for 24 hours to obtain a fine fibrous cellulose-containing sheet A to be an absorption layer later. The thickness of the fine fibrous cellulose-containing sheet A was 50 μm.

[Formation of container]
A commercially available paper cup whose inner surface was laminated with polyethylene (a paper cup composed of a tubular body member and a bottom member, having an opening diameter of 70.5 mm and a total height of 67.5 mm) was prepared. The fine fibrous cellulose-containing sheet A was cut into a shape covering the outer peripheral surface at a height of up to 75% of the total height from the bottom surface of the paper cup (the cut shape is a truncated cone). Next, a UV curable acrylic resin adhesive (manufactured by Aica Kogyo Co., Ltd., Z-587-16) was applied to one surface of the fine fibrous cellulose-containing sheet A after cutting using a paintbrush. The fine fibrous cellulose-containing sheet A was attached to the paper cup so that the coated surface of the adhesive was in contact with the outer peripheral surface of the paper cup. At this time, the shorter arc of the fine fibrous cellulose-containing sheet A and the bottom of the body member of the paper cup were attached so as to coincide with each other. Further, with the paper cup tilted sideways, the UV curable acrylic resin adhesive is cured by passing it through a UV conveyor device (ECS-4011GX manufactured by Eye Graphics Co., Ltd.) set to an ultraviolet irradiation amount of 200 mJ / cm ^2. I let you. Furthermore, with the paper cup tilted sideways, the paper cup is rotated 90 ° around the line connecting the center point of the bottom surface and the center point of the opening, and then passed through the UV conveyor device three times. The acrylic resin adhesive was cured. By the above procedure, a container having a base material layer containing paper and polyethylene, an adhesive layer containing acrylic resin, and an absorption layer containing fine fibrous cellulose was formed.

[Example 2]
[Dissolution of polyethylene oxide]
Polyethylene oxide (PEO-18 manufactured by Sumitomo Seika Chemical Co., Ltd.) was added to ion-exchanged water so as to have a mass of 1% by mass, and the mixture was stirred for 1 hour to dissolve. An aqueous polyethylene oxide solution was obtained by the above procedure.

[Preparation of fine fibrous cellulose-containing sheet]
The fine fibrous cellulose dispersion A prepared in Example 1 and the polyethylene oxide aqueous solution were each diluted with ion-exchanged water so that the solid content concentration was 0.6% by mass. Next, the diluted polyethylene oxide aqueous solution was mixed with 100 parts by mass of the diluted fine fibrous cellulose dispersion to 20 parts by mass to obtain a mixed solution B. Further, the mixed solution B was weighed so that the finished basis weight of the sheet was 75 g / m ² , and developed on a commercially available transparent acrylic plate. A frame for damming (inner dimensions 180 mm × 180 mm, height 50 mm) was arranged on the acrylic plate so as to have a predetermined basis weight. Then, it was dried in a dryer at 70 ° C. for 24 hours to obtain a fine fibrous cellulose-containing sheet B to be an absorption layer later. The thickness of the fine fibrous cellulose-containing sheet B was 50 μm.

[Formation of container]
Similar to [Formation of Container] of Example 1 except that the above-mentioned fine fibrous cellulose-containing sheet B was used instead of the fine fibrous cellulose-containing sheet A, a base material layer, an adhesive layer, and an absorption layer were provided. A container was formed.

[Example 3]
In [Formation of Container] of Example 1, instead of a paper cup, a commercially available polystyrene cup (a cup composed of a tubular body member and a bottom member, having an opening diameter of 70.0 mm and a total height of 68.6 mm). A container having a base material layer containing polystyrene, an adhesive layer containing an acrylic resin, and an absorption layer containing fine fibrous cellulose was formed in the same manner as in Example 1 except that the above was used.

[Example 4]
In [Formation of Container] of Example 2, instead of a paper cup, a commercially available polystyrene cup (a cup composed of a tubular body member and a bottom member, having an opening diameter of 70.0 mm and a total height of 68.6 mm). In the same manner as in Example 2 except that the above was used, a container having a base material layer containing polystyrene, an adhesive layer containing an acrylic resin, and an absorption layer containing fine fibrous cellulose was formed.

[Example 5]
The wrapping paper (manufactured by Oji F-Tex Co., Ltd., graphan; thickness 30 μm) was cut into the same shape as the fine fibrous cellulose-containing sheet A cut in [Formation of Container] of Example 1. After immersing this wrapping paper in ion-exchanged water for 10 seconds, it was wrapped around the container obtained in Example 1 so as to overlap the portion where the fine fibrous cellulose-containing sheet A exists, and allowed to stand. Further, the paper cup was dried in a dryer at 50 ° C. for 24 hours with the bottom surface facing down. By the above procedure, a container having a base material layer containing paper and polyethylene, an adhesive layer containing acrylic resin, an absorption layer containing fine fibrous cellulose, and a permeable layer made of paper was formed.

[Example 6]
In [Formation of Container] of Example 1, a container was formed by the following procedure without using an acrylic resin adhesive.
A commercially available paper cup whose inner surface was laminated with polyethylene (a paper cup composed of a tubular body member and a bottom member, having an opening diameter of 70.5 mm and a total height of 67.5 mm) was prepared. The fine fibrous cellulose-containing sheet A was cut into a shape covering the outer peripheral surface at a height of up to 75% of the total height from the bottom surface of the paper cup (the cut shape is a truncated cone). Next, the cut fine fibrous cellulose-containing sheet A was immersed in ion-exchanged water for 10 seconds. This fine fibrous cellulose-containing sheet A was attached to a paper cup. At this time, the shorter arc of the fine fibrous cellulose-containing sheet A and the bottom of the body member of the paper cup were attached so as to coincide with each other. Further, the paper cup was dried in a dryer at 50 ° C. for 24 hours with the bottom surface facing down. By the above procedure, a container having a base material layer containing paper and polyethylene and an absorption layer containing fine fibrous cellulose was formed.

[Example 7]
In Example 1 [Preparation of fine fibrous cellulose-containing sheet], the mixed solution A was weighed so that the finished basis weight of the sheet was 18 g / m ² , and the mixture was developed on a commercially available transparent acrylic plate. In the same manner as in Example 1, a container having a base material layer containing paper and polyethylene, an adhesive layer containing acrylic resin, and an absorption layer containing fine fibrous cellulose was formed. Here, the thickness of the fine fibrous cellulose-containing sheet was 15 μm.

[Comparative Example 1]
In Example 1, a container provided only with a base material layer containing paper and polyethylene without laminating the fine fibrous cellulose-containing sheet A was prepared and used for the measurement and evaluation described later.

[Comparative Example 2]
In [Preparation of Fine Fibrous Cellulose-Containing Sheet] of Example 1, a sheet composed only of polyvinyl alcohol was prepared without mixing the fine fibrous cellulose dispersion A. Here, the thickness of the sheet was 50 μm. Other procedures were the same as in Example 1 to form a container having a base material layer containing paper and polyethylene, an adhesive layer containing acrylic resin, and an absorption layer containing polyvinyl alcohol.

[Comparative Example 3]
In [Preparation of Fine Fibrous Cellulose-Containing Sheet] of Example 2, a sheet composed only of polyethylene oxide was prepared without mixing the fine fibrous cellulose dispersion A. Further, the polyethylene oxide aqueous solution was weighed so that the finished basis weight of the sheet was 63.5 g / m ² , and developed on a commercially available transparent acrylic plate. Here, the thickness of the sheet was 50 μm. Other procedures were the same as in Example 2 to form a container having a base material layer containing paper and polyethylene, an adhesive layer containing acrylic resin, and an absorption layer containing polyethylene oxide.

[Comparative Example 4]
In Example 3, a container provided only with a polystyrene base material layer without laminating the fine fibrous cellulose-containing sheet A was prepared and used for the measurement and evaluation described later.

[Comparative Example 5]
In [Preparation of fine fibrous cellulose-containing sheet] of Example 3, a sheet composed only of polyvinyl alcohol without mixing the fine fibrous cellulose dispersion A was prepared. Here, the thickness of the sheet was 50 μm. Other procedures were the same as in Example 3 to form a container having a base material layer containing polystyrene, an adhesive layer containing acrylic resin, and an absorption layer containing polyvinyl alcohol.

[Comparative Example 6]
In [Preparation of Fine Fibrous Cellulose-Containing Sheet] of Example 4, a sheet composed only of polyethylene oxide was prepared without mixing the fine fibrous cellulose dispersion A. Further, the polyethylene oxide aqueous solution was weighed so that the finished basis weight of the sheet was 63.5 g / m ² , and developed on a commercially available transparent acrylic plate. Here, the thickness of the sheet was 50 μm. Other procedures were the same as in Example 4 to form a container having a base material layer containing polystyrene, an adhesive layer containing an acrylic resin, and an absorption layer containing polyethylene oxide.

[Comparative Example 7]
In [Formation of Container] of Example 1, a wrapping paper (manufactured by Oji F-Tex Co., Ltd., graphan; thickness 30 μm) was used instead of the fine fibrous cellulose-containing sheet A. Other procedures were the same as in Example 1 to form a container having a base material layer containing paper and polyethylene, an adhesive layer containing acrylic resin, and a transparent layer made of paper.

[Measurement]
[Fiber width]
The fiber width of the fine fibrous cellulose was measured by the following method. The supernatant of the fine fibrous cellulose dispersion obtained by treatment with a wet atomizing device is mixed with water so that the concentration of the fine fibrous cellulose is 0.01% by mass or more and 0.1% by mass or less. It was added dropwise to the diluted and hydrophilized carbon grid film. This was dried, stained with uranyl acetate, and observed with a transmission electron microscope (JEOL-2000EX, manufactured by JEOL Ltd.).

[Amount of phosphorous acid group]
The amount of phosphite groups in the fine fibrous cellulose is a fiber prepared by diluting a fine fibrous cellulose dispersion containing the target fine fibrous cellulose with ion exchange water so that the content is 0.2% by mass. The cellulose-like cellulose-containing slurry was treated with an ion exchange resin and then titrated with an alkali.
For the treatment with the ion exchange resin, a strongly acidic ion exchange resin (Amberjet 1024; Organo Corporation, conditioned) with a volume of 1/10 is added to the fibrous cellulose-containing slurry, and the mixture is shaken for 1 hour. , The resin and the slurry were separated by pouring on a mesh having a mesh size of 90 μm.
For titration using alkali, the change in pH value indicated by the slurry is measured while adding 10 μL of a 0.1 N sodium hydroxide aqueous solution to the fibrous cellulose-containing slurry treated with an ion exchange resin every 5 seconds. I went by doing. The titration was carried out while blowing nitrogen gas into the slurry from 15 minutes before the start of the titration. In this neutralization titration, two points are observed in which the increment (differential value of pH with respect to the amount of alkali dropped) becomes maximum in the curve plotting the measured pH with respect to the amount of alkali added. Of these, the maximum point of the increment obtained first when alkali is added is called the first end point, and the maximum point of the increment obtained next is called the second end point (FIG. 4). The amount of alkali required from the start of the titration to the first end point is equal to the amount of the first dissociated acid in the slurry used for the titration. Further, the amount of alkali required from the start of titration to the second end point becomes equal to the total amount of dissociated acid in the slurry used for titration. The amount of alkali (mmol) required from the start of titration to the first end point divided by the solid content (g) in the slurry to be titrated was defined as the amount of phosphite groups (mmol / g).

[Water absorption rate of container]
A 5 cm square test piece (a piece in which an absorption layer and a base material layer were laminated) was cut out from the body member of the container obtained in Examples and Comparative Examples. At this time, one end of the test piece was cut out so as to be the bottom of the body member. Then, after measuring the weight W _A of the test piece was held for 24 hours by immersion in deionized water. Pulling thereafter specimens from the ion exchange water, after wiping off the water attached to the test piece surface with a Kimwipe and weighed W _B of the test piece. Weight W _A, from W _B, was calculated water absorption water absorption vessel according to Equation 1 below.
Water absorption _{(%) = (W B -W} A) / W A × 100 ... (Equation 1)

[Haze of container]
From the containers obtained in Examples and Comparative Examples, a 5 cm square test piece (a piece in which an absorption layer and a base material layer were laminated) was cut out in the same manner as in [Water absorption rate of container]. For this test piece, the haze measured by a D65 light source was measured using a haze meter (HM-150, manufactured by Murakami Color Technology Research Institute) in accordance with JIS K 7136.

[Evaluation]
[Adhesion of condensed water]
Ion-exchanged water cooled to 5 ° C. was poured into the containers obtained in Examples and Comparative Examples from the bottom surface of the container to a height of 75% of the total height, and then allowed to stand in an environment of 28 ° C. and 80% relative humidity for 10 minutes. After standing, the outer peripheral surface at a height of up to 75% from the bottom surface of the container was observed, and the degree of adhesion of condensed water to the container was evaluated according to the following criteria.
Evaluation 5: No condensation water adheres to the observation part.
Evaluation 4: The degree of condensation water adhesion is clearly less than that of a general paper cup (corresponding to Comparative Example 1).
Evaluation 3: The degree of condensation water adhesion is slightly less than that of a general paper cup (corresponding to Comparative Example 1).
Evaluation 2: The degree of adhesion of condensed water is equivalent to that of a general paper cup (corresponding to Comparative Example 1).
Evaluation 1: The degree of condensation water adhesion is higher than that of a general paper cup (corresponding to Comparative Example 1).

[Visibility of contents]
The blue aqueous dye was diluted with ion-exchanged water to 1% by mass and poured from the bottom of the container to a height of 75% of the total height. Next, the container was observed from the side, and the visibility of the contents was evaluated according to the following criteria.
Evaluation 3: The blue color indicated by the contents can be clearly confirmed.
Evaluation 2: It can be confirmed that the blue color indicated by the contents is unclear.
Evaluation 1: The blue color indicated by the contents cannot be confirmed.

As is clear from the table, in the container of the example provided with the absorption layer containing the fine fibrous cellulose, the adhesion of condensed water was suppressed as compared with the container obtained in the comparative example. In the containers of Examples 3 and 4 in which polystyrene was used as the base material layer and the absorption layer containing fine fibrous cellulose was provided, the visibility of the contents was also good. In addition, the container of Example 5 provided with the transparent layer had a good usability.

20 Base material layer 25 Adhesive layer 30 Absorbent layer 40 Permeable layer 100 Container

Claims (11)

It includes a base material layer and an absorption layer,
A container with an opening on the top surface
The absorption layer contains fibrous cellulose having a fiber width of 1000 nm or less and having a phosphorous acid group or a substituent derived from a phosphorous acid group.
The thickness of the absorption layer is 10 μm or more.
The absorption layer is a container arranged on the outer surface side of the base material layer. It is composed of a body member and a bottom member.
The container according to claim 1, wherein the body member includes the base material layer and the absorption layer. The container according to claim 1 or 2, wherein the base material layer contains at least one selected from pulp, resin, glass and metal. The absorption layer has a fiber width of 1000 nm or less, and any one of claims 1 to 3 containing a fibrous cellulose having a phosphorous acid group or a substituent derived from a phosphorous acid group, and a hydrophilic polymer. The container according to item 1. The container according to claim 4, wherein the hydrophilic polymer is at least one selected from polyvinyl alcohol and polyethylene oxide. The container according to any one of claims 1 to 5 , wherein the water absorption rate calculated by the following formula 1 in the region (X) in which the absorption layer is laminated on the base material layer is 80% or more.
Formula 1: water absorption _{(%) = (W B -W} A) / W A × 100
Here, W _B represents the weight of the region (X) after immersion for 24 hours in deionized water, W _A represents the weight of the region (X) prior to immersion in deionized water. The container according to any one of claims 1 to 6 , wherein the haze of the region (X) in which the absorption layer is laminated on the base material layer is 70% or less. The container according to any one of claims 1 to 7 , wherein the absorption layer is laminated on the base material layer via an adhesive layer. It also has a transparent layer
The container according to any one of claims 1 to 8 , wherein the permeable layer is arranged on the outer surface side of the absorbing layer. The container according to any one of claims 1 to 9 , wherein a part of the base material layer is exposed on the outer surface. The container according to any one of claims 1 to 10 , which is for accommodating cold articles.