JP2019094077A - container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a container having a novel form capable of suppressing the occurrence of dew condensation. The present invention includes a base material layer and an absorption layer, the absorption layer contains fibrous cellulose having a fiber width of 1000 nm or less, and the absorption layer is arranged on the outer surface side of the base material layer. Regarding the container. [Selection diagram] Fig. 1

Description

  The present invention relates to a container. Specifically, the present invention relates to a container comprising an absorbent layer comprising fine fibrous cellulose.

  Paper containers and plastic containers are widely used as containers for filling food and the like. For example, as a container for filling a beverage, a cup-shaped container or a cup-shaped container for filling and packaging a food such as yoghurt or ice cream is widely used. As such containers, paper containers having a water-repellent laminate layer and single-layer plastic containers are widely distributed.

  In recent years, containers in which various ideas have been made to enhance functionality have been developed. For example, Patent Document 1 discloses a composite cup provided with an inner cup made of plastic film and an outer cup made of paper. Here, by overlapping the inner cup and the outer cup, heat insulation performance, heat retention performance, and cold storage performance can be imparted, and further, a device for preventing condensation from being dissipated to the surrounding environment is made.

  Patent Documents 2 and 3 disclose a paper cup provided with a paper base and a barrier layer containing cellulose fibers. Here, it is considered to improve the barrier property of the paper cup by using a chemically treated cellulose fiber for the barrier layer.

JP, 2014-221656, A JP, 2017-190541, A JP, 2017-190544, A

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

In the prior art, for example, there is proposed a technique for suppressing the condensation water from being dissipated to the surrounding environment by providing an inner cup and an outer cup, but the occurrence of condensation (the occurrence of condensation There is no disclosure of a technique for suppressing adhesion).
Therefore, an object of the present invention is to provide a novel form of container which can suppress the occurrence of condensation.

As a result of intensive studies to solve the above problems, the present inventors have found that, in a container provided with a base material layer and an absorption layer disposed on the outer surface side of the base material layer, It has been found that by containing fibrous cellulose having a width of 1000 nm or less, a container in which the occurrence of condensation is suppressed can be obtained.
Specifically, the present invention has the following configuration.

[1] A substrate layer and an absorption layer,
The absorption layer contains fibrous cellulose having a fiber width of 1000 nm or less,
A container wherein the absorbent layer is disposed on the outer surface side of the base layer.
[2] It consists of a body member and a bottom member,
The container according to [1], wherein the body member comprises a base material layer and an absorbent 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 container according to any one of [1] to [3], wherein the absorbent layer contains fibrous cellulose having a fiber width of 1000 nm or less and a hydrophilic polymer.
[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 fibrous cellulose is a fibrous cellulose having a phosphate group or a substituent derived from a phosphate group.
[7] The container according to any one of [1] to [6], wherein the thickness of the absorbing layer is 10 μm or more.
[8] The container according to any one of [1] to [7], wherein the water absorption coefficient calculated by the following formula 1 in the region (X) in which the absorbent layer is laminated on the base material layer is 80% or more.
Formula 1: Water absorption rate (%) = (W _B −W _A ) / W _A × 100
Here, W _B represents the weight of the area (X) after being immersed in ion exchange water for 24 hours, and W _A represents the weight of the area (X) before being immersed in ion exchange water.
[9] The container according to any one of [1] to [8], wherein the haze of the region (X) in which the absorbent layer is laminated on the base material layer is 70% or less.
[10] The container according to any one of [1] to [9], wherein the absorbent layer is laminated to the base material layer via an adhesive layer.
[11] Furthermore, it has a permeable layer,
The permeable layer is a container in any one of [1]-[10] arrange | positioned on the outer surface side rather than the absorption layer.
[12] The container according to any one of [1] to [11], wherein a part of the base material layer is exposed to the outer surface.
[13] The container according to any one of [1] to [12], which is for storing cold articles.

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

FIG. 1 is a schematic view illustrating one 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 one embodiment of the container of the present invention. FIG. 4 is a graph showing the relationship between the amount of dropped NaOH and the electrical conductivity of the fiber material having a phosphate group. FIG. 5 is a graph showing the relationship between the amount of dropped NaOH and the electrical conductivity for a fiber material having a carboxyl group. FIG. 6 is a plan view for explaining the layer structure of the container of the present invention. FIG. 7 is a plan view for explaining the layer structure of the container of the present invention.

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

(container)
The present invention relates to a container comprising a substrate layer and an absorbent layer. Here, the absorption layer contains fibrous cellulose having a fiber width of 1000 nm or less, and the absorption layer is disposed on the outer surface side of the base layer.

  FIG. 1 is a schematic diagram illustrating one embodiment of a container 100 of the present invention. As shown in FIG. 1, the container 100 includes a base layer 20 on the inner side and an absorbent layer 30 on the outer side. In FIG. 1, the layer configurations of the base material layer 20 and the absorption layer 30 are drawn for easy understanding, and therefore the thickness of each layer and the ratio of the thickness are not necessarily the same as the actual configuration of the container. Inside the base material layer 20, an accommodating portion for accommodating the contents is formed. The base layer 20 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 be provided on the surface of the base layer 20 on the side of the housing portion.

FIG. 2 is a top plan view of the container 100 of the present invention. In FIG. 2, the layer configurations of the base material layer 20 and the absorption layer 30 are drawn for easy understanding, so the thickness of each layer and the ratio of the thickness are not necessarily the same as the actual configuration of the container.
As shown in FIG. 2, the absorbent layer 30 is provided on the outer surface side of the base layer 20. As shown in FIG. 2, the absorbent layer 30 may be laminated so as to be in direct contact with the substrate layer 20. Further, as shown in FIG. 2, the absorbing layer 30 may be a layer constituting the outermost surface of the container 100. In addition, another layer may be provided between the absorption layer 30 and the base material layer 20 as described later. For example, an adhesive layer 25 may be provided between the absorbent layer 30 and the base layer 20. Further, as 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-mentioned configuration, it is possible to suppress the occurrence of dew condensation on the outer peripheral surface of the container even when a cold article such as a cold beverage is stored in the container of the container. 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 condensed water, it can absorb condensed water generated on the outer peripheral surface of the container, thereby suppressing adhesion of the condensed water on the outer peripheral surface of the container. Thus, the container of the present invention can suppress the occurrence of dew condensation, and can reduce the discomfort associated with the hand condensation or dripping of dew condensation water during use.

  As mentioned above, since the container of the present invention is provided with an absorption layer capable of absorbing dew condensation water, it is suitable for containing a cold article as a content. That is, the container of the present invention is preferably used for cold goods storage applications. Among them, the container of the present invention is particularly preferably used for cold food storage and cold beverage storage.

  Moreover, the container of this invention is a container with which the base material layer and the absorption layer were united. That is, the base material layer and the absorption layer constitute one laminate, and the laminate is formed into a container shape. For this reason, the container of the present invention is easy to manufacture, and has an advantage such as saving storage space because it can be made compact.

  In addition, since the container of this invention has the said structure, it is excellent also in heat retention and heat insulation. That is, the absorbent layer functions to make it difficult to convey the heat of the contents to the user's hand when the warm water etc. are stored in the storage section, and also functions to keep the contents cool. Furthermore, in the container of the present invention, the absorbent layer can also exhibit a non-slip function. Since the absorbent layer is familiar to the user's handle, the container can be prevented from sliding off the handle.

As shown in FIG. 1, the container 100 of the present invention preferably comprises a body member and a bottom member. Thus, it is preferable that the container 100 of the present invention is provided with an opening on the top surface opposite to the bottom surface. The container 100 may further include a lid member, and in such a case, the lid member is preferably engaged or joined to the body member so as to cover the opening.
Although the container 100 is preferably formed by combining at least two members such as a body member and a bottom member, the container 100 may be formed of a member which is not distinguished between the body member and the bottom member. For example, the container 100 may be in the shape of a bowl made of a series of members or in the shape of a rectangular parallelepiped, or may be in the shape of an inverted triangle formed by assembling a plurality of triangular members.

  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 square, triangle, oval 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 is a side wall (side surface) of the circular bottom member and is assembled in a tubular shape.

  When a container is comprised from a trunk | drum member and a bottom member, it is preferable that a trunk | drum member is what is provided with 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 absorbent layer may be provided only on the side of the container. In this case, the base material layer of the bottom member is exposed to the outer surface at the bottom surface.

If the container is composed of a body member and a bottom member, as shown in FIG. 1, the absorbent layer 30 may be provided on the entire body member, as shown in FIG. The absorbent layer 30 may be provided on a part of the body member. When the absorbent 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. In the case where the absorbing layer 30 is provided on a part of the body member, condensation generated in a portion without the absorbing layer 30 is absorbed by the partially provided absorbing layer 30, thereby dissipating to the surrounding environment. It can also be prevented. In FIG. 3, the absorbent layer 30 is provided below the body member, and the base layer 20 is exposed above the body member. Thus, it is preferable that the absorbent layer 30 be provided in the region from the bottom side of the body member to any height. In this case, the arbitrary height at which the absorbent layer 30 is provided is preferably 50% or more of the height of the container, more preferably 60% or more, and 70% or more. It is further preferred that Thereby, the absorption layer 30 can fully absorb dew condensation water, and can also suppress the manufacturing cost of the container 100.
In FIG. 3, the layer configurations of the base layer 20 and the absorption layer 30 are drawn for easy understanding, so the thickness of each layer and the ratio of the thickness are not necessarily the same as the actual configuration of the container.

  The absorption layer may be provided only in the central region in the height direction of the body member. For example, an absorbing layer may be provided in the vicinity of the grip portion of the user in the trunk member. In addition, the absorbing layer may be provided intermittently along the circumferential direction of the outer peripheral surface of the trunk member and in the height direction. That is, the absorbing layer may be provided in a stripe shape on the body member. Further, the absorbent layer may be provided in a pattern on the body member, and may be provided, for example, in a polka-dot pattern or a lattice pattern. In such a case, the absorption layer is preferably provided in an area of 40% or more of the surface area of the body member, more preferably in an area of 50% or more, and more preferably 60% or more. More preferably, it is provided in the area. Thereby, an absorption layer can exhibit a non-slip function, absorbing condensation water more effectively.

  The plane area of the opening of the container and the plane area of the bottom member may be the same or different. In particular, when the container is used for storing cold beverages, as shown in FIG. 1, it is preferable that the plane area of the opening> the plane area of the bottom member.

In the container of the present invention, the absorbent layer is excellent in water absorption. For this reason, the absorption layer can absorb the dew condensation water which arises when a cold article is stored as a content, and it can control that dew condensation water adheres to the container surface by this. Specifically, the water absorption of the container calculated by the following formula 1 in the region (X) where the absorbent layer is laminated on the base material layer is preferably 80% or more, and more preferably 90% or more It is preferably 100% or more, more preferably 120% or more, still more preferably 180% or more, and particularly preferably 200% or more. In addition, the upper limit of a water absorption is not specifically limited, For example, it can be 5000%.
Formula 1: Water absorption rate (%) = (W _B −W _A ) / W _A × 100
Here, W _B represents the weight of the area (X) after being immersed in ion exchange water for 24 hours, and W _A represents the weight of the area (X) before being immersed in ion exchange 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 stacked is cut out into a 5 cm square to obtain a test piece, and the weight before and after immersing the test piece in ion exchange water 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 absorbing layer is excellent in transparency. For this reason, the transparency of the whole container can be improved by using a transparent material also for a base material layer, and the haze value of a container can be reduced. In such a case, the contents stored in the storage portion can be viewed from the outside, and the design can be enhanced. For example, the haze value of the region (X) in which the absorbent layer is laminated on the base material layer in any one surface of the container may be 70% or less, 60% or less, or 30% or less 10% or less may be sufficient.
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 into, for example, 5 cm square to make a test piece, and using a haze meter (HM-150 made by Murakami Color Research Laboratory Co., Ltd.) It measures using a D65 light source according to JIS K 7136. In addition, the size of the test piece used when measuring haze is not specifically limited.

  In addition, it is preferable that the haze value of an absorption layer is also in the said range. That is, it is preferable that the absorption layer has high transparency. Thereby, for example, even when characters and patterns are printed on the base material layer, the absorbent layer does not reduce the visibility of the characters and patterns. When measuring the haze value of the absorption layer, after exfoliating the absorption layer from the container, using a haze meter (HM-150, manufactured by Murakami Color Research Laboratory Co., Ltd.), for example, for a test piece cut into 5 cm square According to JIS K 7136, the haze by D65 light source is measured.

(Base material layer)
The container of the present invention comprises a substrate 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 side of the housing portion.

  The base layer is preferably a layer containing at least one selected from pulp, resin, glass and metal. Among them, the base material layer is more preferably a layer containing at least one selected from pulp and resin. In addition, when the base material layer is comprised from resin, the light transmittance of a base material layer can be improved, and, thereby, the haze value of a container can be reduced. Thereby, the visibility of the content of a container can be improved and the designability can also be improved.

  When the base material layer is a layer containing pulp, it is preferable to use, as the base material layer, 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. In this case, examples of resin components for laminating include polyolefin resins, epoxy resins, urethane resins, isocyanate resins, polyester resins, plant-derived materials (bioplastics), polyethylene resins, polypropylene resins and the like. be able to. Among them, polyethylene resins and polypropylene resins which 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, and linear low density polyethylene (LLDPE) is particularly preferably used. Moreover, as a polypropylene resin, polypropylene resin, a propylene-ethylene random copolymer, and a propylene-ethylene block copolymer are mentioned.

  When laminating the resin component as described above, for example, methods such as a wet lamination method, a dry lamination method, a solventless 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 previously subjected to known surface treatment such as corona treatment, ozone treatment, plasma treatment, glow discharge treatment, oxidation treatment using chemicals, and the like. In addition, a primer coat layer, an anchor coat layer, an adhesive layer or the like may be provided between the paper layer and the laminate layer of the resin component.

  In addition, in this specification, a pulp means the cellulose fiber component whose fiber width is larger than 1000 nm, and is distinguished from the fine fibrous cellulose mentioned later. The base material layer may contain fine fibrous cellulose, but the content of 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. Preferably, it is 0% by mass or less.

  When the base material layer is a layer containing a resin, the resin species thereof is not particularly limited, and examples thereof include polystyrene resins, polyolefin resins, polyester resins, acrylic resins, and the like. It is preferable that resin which comprises a base material layer is resin type with high transparency.

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

  The thickness of the substrate layer is not particularly limited, but is preferably 10 μm or more, more preferably 50 μm or more, and still more preferably 100 μm or more, and the thickness of the substrate layer Is preferably 5000 μm or less.

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

(Absorbent layer)
The container of the present invention comprises an absorbent layer on the outer surface side of the above-mentioned base layer. The absorbing layer contains fibrous cellulose having a fiber width of 1000 nm or less. In the present specification, fibrous cellulose having a fiber width of 1000 nm or less is also referred to as fine fibrous cellulose.

  The absorbent layer preferably further contains a hydrophilic polymer in addition to fibrous cellulose having a fiber width of 1000 nm or less. Examples of hydrophilic polymers include carboxyvinyl polymer, polyvinyl alcohol, alkyl methacrylate-acrylic acid copolymer, polyvinyl pyrrolidone, sodium polyacrylate, polyethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol And 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 absorbing 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 absorbing layer. Is more preferred. Further, 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 absorbent 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 and 15% by mass or more based on the total mass of the absorbing layer. It is more preferable that it is 20 mass% or more. Further, the content of the hydrophilic polymer is preferably 99.5% by mass or less, more preferably 99.0% by mass or less, and more preferably 95.0% by mass or less based on the total mass of the absorbing layer. It is further preferred that

  The absorbing layer may contain optional components other than the components described above. Optional components include, for example, surfactants, organic ions, coupling agents, inorganic layered compounds, inorganic compounds, leveling agents, preservatives, antifoaming agents, organic particles, lubricants, antistatic agents, ultraviolet protective agents, Dyes, pigments, stabilizers, magnetic powders, orientation accelerators, plasticizers, dispersants, crosslinking agents and the like can be mentioned.

  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 20% by mass or less based on the total mass of the absorption layer. Is more preferred.

The absorption layer is excellent in water absorption, and the absorption coefficient 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, still more preferably 180% or more, and particularly preferably 200% or more. In addition, the upper limit of a water absorption is not specifically limited, For example, it can be 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 exchange water for 24 hours, and W _a represents the weight of the absorption layer before being immersed in ion exchange water. In addition, when calculating a water absorption rate in this specification, it is calculated by, for example, peeling the absorption layer from a container and measuring the weight before and behind immersing the absorption layer cut out into 5 cm square after that in ion exchange water. Do. The size of the test piece used when calculating the water absorption rate is not particularly limited.

  The haze value of the absorbing layer is preferably 70% or less, more preferably 60% or less, still more preferably 30% or less, and particularly preferably 10% or less. The haze value of the absorption layer is measured according to JIS K 7136 using, for example, a haze meter (HM-150 manufactured by Murakami Color Research Laboratory Co., Ltd.) for a test piece cut into 5 cm square after peeling the absorption layer from the container. It is the value which measured the haze by D65 light source according to it. In addition, the size of the test piece used when measuring haze is not specifically limited.

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

  A printing layer may be provided on at least one of the inner surface and the outer surface of the absorbent layer. For example, characters, patterns, etc. may be printed on the outer surface of the absorbent layer. The printing layer is provided by a known method in accordance with the material of the outer surface of the absorbent layer.

<Fine fibrous cellulose>
The absorbing layer contains fibrous cellulose having a fiber width of 1000 nm or less. The fiber width of fibrous cellulose can be measured, for example, by electron microscopic observation.

  The average fiber width of fibrous cellulose is, for example, 1000 nm or less. The average fiber width of the fibrous cellulose is, for example, preferably 2 nm or more and 1000 nm or less, more preferably 2 nm or more and 100 nm or less, still more preferably 2 nm or more and 50 nm or less, and 2 nm or more and 10 nm or less Particularly preferred. By setting the average fiber width of the fibrous cellulose to 2 nm or more, it is possible to suppress dissolution in water as cellulose molecules and to more easily express the effect of improving the strength, rigidity, and dimensional stability by the fibrous cellulose. it can. The fibrous cellulose is, for example, monofibrillar 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 obtain a sample for TEM observation I assume. If wide fibers are included, an SEM image of the surface cast on glass may be observed. Next, observation with an electron microscope image is performed at a magnification of 1000 times, 5000 times, 10000 times or 50000 times depending on the width of the fiber to be observed. However, the sample, observation conditions and magnification are adjusted to satisfy the following conditions.
(1) One straight line X is drawn at an arbitrary position in the observation image, and 20 or more fibers cross the straight line X.
(2) Draw a straight line Y intersecting perpendicularly with the straight line in the same image, and 20 or more fibers cross the straight line Y.
The width of the fiber intersecting the straight line X and the straight line Y is visually read for the observation image satisfying the above conditions. In this way, three or more sets of observation images of surface portions not overlapping each other at least are obtained. Then, for each image, the width of the fiber intersecting the straight line X and the straight line Y is read. Thereby, a fiber width of at least 20 × 2 × 3 = 120 is read. And let the average value of the read fiber width be an average fiber width of fibrous cellulose.

  The fiber length of the fibrous cellulose is not particularly limited, but is preferably 0.1 μm to 1000 μm, more preferably 0.1 μm to 800 μm, and still more preferably 0.1 μm to 600 μm. preferable. By setting the fiber length within the above range, it is possible to suppress the destruction of the crystalline region of fibrous cellulose. It also becomes possible to make the slurry viscosity of fibrous cellulose into a suitable range. In addition, the fiber length of fibrous cellulose can be calculated | required from the image analysis by TEM, SEM, and AFM, for example.

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

  The proportion of crystalline form I in fine fibrous cellulose is, for example, preferably 30% or more, more preferably 40% or more, and still more preferably 50% or more. Thereby, further excellent performance can be expected in terms of heat resistance and low linear thermal expansion. With regard to the degree of crystallinity, the X-ray diffraction profile is measured, and the pattern is determined by a conventional method (Seagal et al., Textile Research Journal, 29: 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, an absorbent layer containing fine fibrous cellulose can be easily formed. In addition, sufficient viscosity can be easily obtained when the solvent dispersion is prepared. By setting the axial ratio to the upper limit value or less, for example, when treating fibrous cellulose as an aqueous dispersion, it is preferable in that handling such as dilution is facilitated.

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

The fibrous cellulose in the present embodiment has, for example, at least one of an ionic substituent and a nonionic substituent. It is more preferable that fibrous cellulose has an ionic substituent from a viewpoint of improving the dispersibility of the fiber in a dispersion medium, and raising the disintegration efficiency in a disintegration process. The ionic substituent can include, for example, either or both of an anionic group and a cationic group. Moreover, as a nonionic substituent, an alkyl group, an acyl group, etc. can be included, for example. In the present embodiment, it is particularly preferable to have an anionic group as the ionic substituent.
In addition, the process which introduce | transduces an ionic substituent does not need to be performed to fibrous cellulose. The fiber width of such fibrous cellulose is 10 to 1000 nm, and the distribution of the fiber width tends to be wider as compared with fibrous cellulose having an ionic substituent or a nonionic substituent.

  As an anionic group as an ionic substituent, for example, a phosphate group or a substituent derived from a phosphate group (sometimes simply referred to as a phosphate group), a carboxyl group or a substituent derived from a carboxyl group (simply referred to as a carboxyl group) And at least one selected from a sulfone group or a substituent derived from a sulfone group (sometimes referred to simply as a sulfone group), and at least one selected from a phosphoric acid group and a carboxyl group It is more preferably a species, and particularly preferably a phosphate group. When the absorption layer contains fibrous cellulose having a phosphate group, the water absorption of the absorption layer tends to be high, and the occurrence of condensation can be suppressed more effectively.

The phosphate group is, for example, a divalent functional group corresponding to phosphoric acid from which a hydroxyl group has been removed. It is specifically a group represented by -PO ₃ H _2. The substituent derived from the phosphate group includes a substituent such as a salt of a phosphate group and a phosphate ester group. In addition, the substituent derived from a phosphoric acid group may be contained in fibrous cellulose as group (for example, pyrophosphoric acid group) which the phosphoric acid group condensed.
The phosphate group or the substituent derived from the phosphate group is, for example, a substituent represented by the following formula (1).

In formula (1), a, b and n are natural numbers (however, a = b × m). ^{α 1, α 2, ···,} a number of alpha ⁿ and alpha 'is O ^- a and the remainder is either R, the OR. Incidentally, all of the αn and alpha 'is O ^- may be a. R is each a hydrogen atom, a saturated-linear hydrocarbon group, a saturated-branched hydrocarbon group, a saturated-cyclic hydrocarbon group, an unsaturated-linear hydrocarbon group, an unsaturated-branched carbonization It is a hydrogen group, an unsaturated-cyclic hydrocarbon group, an aromatic group, or a derivative thereof.

  Although a methyl group, an ethyl group, n-propyl group, or n-butyl group etc. are mentioned as a saturated-linear hydrocarbon group, It does not specifically limit. Examples of the saturated-branched hydrocarbon group include i-propyl group and t-butyl group, but are not particularly limited. Although a cyclopentyl group, a cyclohexyl group, etc. are mentioned as a saturated cyclic hydrocarbon group, It does not specifically limit. Examples of the unsaturated-linear hydrocarbon group include, but are not particularly limited to, a vinyl group, an allyl group and the like. Examples of unsaturated-branched hydrocarbon groups include i-propenyl group and 3-butenyl group, but are not particularly limited. Although a cyclopentenyl group, a cyclohexenyl group, etc. are mentioned as unsaturated-cyclic hydrocarbon group, It does not specifically limit. As an aromatic group, although a phenyl group or a naphthyl group etc. are mentioned, it does not specifically limit.

  In addition, as a derivative group in R, at least one of functional groups such as a carboxyl group, a hydroxyl group or an amino group is added or substituted to the main chain or side chain of the above various hydrocarbon groups. Although a group is mentioned, it is not limited in particular. Further, the number of carbon atoms constituting the main chain of R is not particularly limited, but is preferably 20 or less, more preferably 10 or less. By setting the number of carbon atoms constituting the main chain of R in the above range, the molecular weight of the phosphate group can be made in an appropriate range, facilitating penetration into the fiber material, and increasing the yield of fine cellulose fibers It can also be done.

β ^{b +} is a monovalent or more cation composed of an organic substance or an inorganic substance. The monovalent or more monovalent cations of organic substances include aliphatic ammonium or aromatic ammonium, and the monovalent or more monovalent cations of inorganic substances include ions of alkali metals such as sodium, potassium or lithium, Examples thereof include cations of divalent metals such as calcium or magnesium, or hydrogen ions, but not particularly limited. These can also be applied combining 1 type or 2 or more types. The monovalent or more monovalent cation composed of an organic substance or an inorganic substance is preferably an ion of sodium or potassium which is not easily yellowed when the fiber material containing β is heated and which is industrially easy to use, but is not particularly limited.

The amount of ionic functional group introduced into the fibrous cellulose is, for example, preferably 0.10 mmol / g or more, more preferably 0.20 mmol / g or more, and more preferably 0.50 mmol or more per 1 g (mass) of fibrous cellulose. It is more preferable that it is / g or more, and it is particularly preferable that it is 1.00 mmol / g or more. The amount of ionic functional group introduced into the fibrous cellulose is, for example, preferably 3.65 mmol / g or less, more preferably 3.50 mmol / g or less, per 1 g (mass) of fibrous cellulose. More preferably, it is not more than .00 mmol / g. By making the introduction amount of the ionic functional group in the above range, it is possible to easily make the fiber raw material finer, and it is possible to improve the stability of the fibrous cellulose. In addition, by setting the introduction amount of the ionic functional group in the above range, good characteristics can be exhibited in a sheet containing fibrous cellulose and the like.
Here, the denominator in the unit mmol / g indicates the mass of fibrous cellulose when the counter ion of the ionic functional group is a hydrogen ion (H ⁺ ).

  The introduction amount of the ionic functional group to the fibrous cellulose can be measured, for example, by the conductivity titration method. In the measurement by the conductivity titration method, the introduced amount is measured by determining the change in conductivity while adding an alkali such as an aqueous sodium hydroxide solution to the obtained fibrous cellulose-containing slurry.

  FIG. 4 is a graph showing the relationship between the amount of dropped NaOH and the electrical conductivity for fibrous cellulose having a phosphate group. The introduction amount of phosphate group to fibrous cellulose is measured, for example, as follows. First, a slurry containing fibrous cellulose is treated with a strongly acidic ion exchange resin. In addition, you may implement the disintegration processing similar to the below-mentioned disintegration processing process with respect to a measuring object before the processing by strongly acidic ion exchange resin as needed. Then, while the aqueous sodium hydroxide solution is added, the change in the electrical conductivity is observed to obtain a titration curve as shown in FIG. As shown in FIG. 4, at the beginning, the electrical conductivity rapidly decreases (hereinafter, referred to as "first region"). Thereafter, the conductivity starts to rise slightly (hereinafter referred to as "the second region"). After that, the increment of conductivity increases (hereinafter, referred to as "third region"). The boundary point between the second area and the third area is defined as a point at which the second derivative value of the conductivity, that is, the change amount of the increment (inclination) of the conductivity is maximum. Thus, three regions appear in the titration curve. Among them, the amount of alkali required in the first region is equal to the amount of strongly acidic groups in the slurry used for titration, and the amount of alkali required in the second region is the amount of weakly acidic groups in the slurry used for titration Become equal. When the phosphoric acid group causes condensation, the weakly acidic group is apparently lost, 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 is the same as the amount of phosphorus atoms regardless of the presence or absence of condensation. For this reason, the amount of introduction of a phosphate group (or amount of phosphate group) or the amount of introduction of a substituent (or amount of substituent) simply means the amount of strongly acidic group. Therefore, the value obtained by dividing the amount of alkali (mmol) required in the first region of the titration curve obtained above by the solid content (g) in the slurry to be titrated is the amount of phosphate group introduced (mmol / g).

  FIG. 5 is a graph showing the relationship between the amount of dropped NaOH and the electrical conductivity for fibrous cellulose having a carboxyl group. The introduction amount of carboxyl groups to fibrous cellulose is measured, for example, as follows. First, a slurry containing fibrous cellulose is treated with a strongly acidic ion exchange resin. In addition, you may implement the disintegration processing similar to the below-mentioned disintegration processing process with respect to a measuring object before the processing by strongly acidic ion exchange resin as needed. Then, while the aqueous sodium hydroxide solution is added, the change in electrical conductivity is observed to obtain a titration curve as shown in FIG. As shown in FIG. 5, the titration curve shows that after the conductivity decreases, the first region until the conductivity increment (slope) becomes almost constant, and then the conductivity increment (slope) increases. It is divided into the second area. The boundary point between the first region and the second region is defined as a point at which the second derivative value of the conductivity, that is, the amount of change in the conductivity increment (slope) becomes maximum. And the value obtained by dividing the amount of alkali (mmol) required in the first region of the titration curve by the solid content (g) in the fine fibrous cellulose-containing slurry to be titrated is the amount of carboxyl group introduced ( It becomes mmol / g).

The above-mentioned carboxyl group introduction amount (mmol / g) is the mass of fibrous cellulose of which the denominator is acid type, so the amount of carboxyl groups possessed by the fibrous cellulose of acid type (hereinafter referred to as carboxyl group amount (acid type Is called). On the other hand, when the counter ion of the carboxyl group is substituted by an arbitrary cation C so as to have a charge equivalent, converting the denominator into the mass of fibrous cellulose when the cation C is a counter ion The amount of carboxyl groups (hereinafter, the amount of carboxyl groups (C type)) possessed by the fibrous cellulose in which the cation C is a counter ion can be determined.
That is, it calculates with the following formula.
Carboxyl group weight (C type) = Carboxyl group weight (acid type) / [1+ (W-1) × (carboxyl group weight (acid type)) / 1000]
W: Formula weight per monovalent C cation (for example, 23 for Na, 9 for Al)

<Production process of fine fibrous cellulose>
<Fiber raw material>
Fine fibrous cellulose is produced from a fiber material containing cellulose. The fiber material containing cellulose is not particularly limited, but it is preferable to use pulp from the viewpoint of availability and low cost. Pulps include, for example, wood pulp, non-wood pulp, and deinked pulp. The wood pulp is not particularly limited. For example, hardwood kraft pulp (LBKP), softwood kraft pulp (NBKP), sulfite pulp (SP), dissolving pulp (DP), soda pulp (AP), unbleached kraft pulp (UKP ) And chemical pulp such as oxygen bleached kraft pulp (OKP), semichemical pulp such as semichemical pulp (SCP) and chemigroundwood pulp (CGP), ground pulp (GP) and thermomechanical pulp (TMP, BCTMP) Mechanical pulp etc. are mentioned. Non-wood pulps include, but are not limited to, cotton-based pulps such as cotton linters and cotton lint, and non-wood-based pulps such as hemp, straw and bagasse. The deinked pulp is not particularly limited, and examples thereof include deinked pulp using waste paper as a raw material. The pulp of this embodiment may be used singly or in combination of two or more.
Among the above-mentioned pulps, wood pulp and deinked pulp are preferable from the viewpoint of availability, for example. Further, among the wood pulps, in view of a high ratio of cellulose and a high yield of fine fibrous cellulose at the time of fibrillation treatment, the decomposition of cellulose in the pulp is small, and a fine fibrous cellulose of long fibers having a large axial ratio can be obtained. From the viewpoint, for example, chemical pulp is more preferable, and kraft pulp and sulfite pulp are more preferable.

  As a fiber material containing cellulose, for example, cellulose contained in ascidians and bacterial cellulose produced by acetic acid bacteria can also be used. Moreover, it can replace with the fiber raw material containing a cellulose, and can also use the fiber which linear nitrogen-containing polysaccharide polymers, such as chitin and chitosan, form.

<Phosphoric acid group introduction process>
The phosphoric acid group introducing step is a reaction with a hydroxyl group possessed by a fiber raw material containing cellulose, so that at least one compound selected from compounds which can introduce a phosphoric acid group (hereinafter also referred to as “compound A”) Is a step of acting on the fiber material containing By this process, a phosphate group-introduced fiber is obtained.

  In the phosphate group introducing step according to the present embodiment, the reaction of the fiber material containing cellulose and the compound A is performed in the presence of at least one selected from urea and its derivative (hereinafter, also referred to as “compound B”) May be On the other hand, the reaction of the fiber material containing cellulose and the compound A may be carried out in the absence of the compound B.

  As an example of the method of causing compound A to act on the fiber material in the coexistence with compound B, a method of mixing compound A and compound B with respect to a dry, wet or slurry fiber material can be mentioned. Among these, it is preferable to use a dry or wet fiber raw material, and in particular, it is preferable to use a dry fiber raw material, because the reaction uniformity is high. The form of the fiber material is not particularly limited, but is preferably, for example, cotton-like or thin sheet-like. The compound A and the compound B may be added to the fiber material in the form of powder or a solution dissolved in a solvent, or in the state of being melted by heating to the melting point or higher. Among them, it is preferable to add in the form of a solution dissolved in a solvent, particularly in the form of an aqueous solution, because the reaction uniformity is high. The compound A and the compound B may be added simultaneously to the fiber material, may be added separately, or may be added as a mixture. The method of 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 taken out after being immersed and absorbed in the solution, The solution may be dropped to the In addition, necessary amounts of Compound A and Compound B may be added to the fiber raw material, and after excess amounts of Compound A and Compound B are respectively added to the fiber raw material, excess Compound A and Compound B are added by pressing or filtration. It may be removed.

  The compound A used in this embodiment includes, but is not particularly limited to, phosphoric acid or a salt thereof, dehydrated condensed phosphoric acid or a salt thereof, phosphoric anhydride (diphosphorus pentaoxide), and the like. As phosphoric acid, those of various purity can be used, and for example, 100% phosphoric acid (orthophosphoric acid) or 85% phosphoric acid can be used. The dehydrated condensed phosphoric acid is obtained by condensing two or more molecules of phosphoric acid by a dehydration reaction, and examples thereof include pyrophosphoric acid and polyphosphoric acid. The phosphate and dehydrated condensed phosphate include lithium salt, sodium salt, potassium salt, ammonium salt and the like of phosphoric acid or dehydrated condensed phosphoric acid, and these can be made to have various degrees of neutralization. Among these, phosphoric acid and phosphoric acid are preferred from the viewpoint of high efficiency of introduction of a phosphoric acid group, easy improvement of defibrillation efficiency in a fibrillation step described later, low cost, and easy industrial application. Sodium salts, potassium salts of phosphoric acid or ammonium salts of phosphoric acid are preferred, and phosphoric acid, sodium dihydrogen phosphate, disodium hydrogen phosphate or ammonium dihydrogen phosphate is more preferred.

  The amount of compound A added to the fiber raw material is not particularly limited. For example, when the amount of compound A added is converted to 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 to 50% by mass, and still more preferably 2% by mass to 30% by mass. By making the addition amount of the phosphorus atom with respect to a fiber raw material into the said range, the yield of fine fibrous cellulose can be improved more. On the other hand, by setting the addition amount of phosphorus atoms to the fiber raw material to the upper limit value or less, it is possible to balance the effect of improving the yield and the cost.

The compound B used in this embodiment is at least one selected from urea and derivatives thereof as described above. As compound B, for example, urea, biuret, 1-phenylurea, 1-benzylurea, 1-methylurea, 1-ethylurea and the like can be mentioned.
From the viewpoint of improving the uniformity of the reaction, the compound B is preferably used as an aqueous solution. Further, from the viewpoint of further improving the homogeneity of the reaction, it is preferable to use an aqueous solution in which both the compound A and the compound B are dissolved.

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

  In the reaction of the fiber material containing cellulose and the compound A, in addition to the compound B, for example, an amide or an amine may be included in the reaction system. Examples of the 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 work as a good reaction catalyst.

  In the phosphoric acid group introducing step, it is preferable to heat treat the fiber material after adding or mixing the compound A and the like to the fiber material. As the heat treatment temperature, it is preferable to select a temperature at which the phosphoric acid group can be efficiently introduced while suppressing the thermal decomposition or hydrolysis reaction of the fiber. The heat treatment temperature is, for example, preferably 50 ° C. or more and 300 ° C. or less, more preferably 100 ° C. or more and 250 ° C. or less, and still more preferably 130 ° C. or more and 200 ° C. or less. For the heat treatment, equipment having various heat media can be used. For example, stirring and drying apparatus, rotary drying apparatus, disk drying apparatus, roll type heating apparatus, plate type heating apparatus, fluidized bed drying apparatus, air flow A drying device, a reduced pressure drying device, an infrared heating device, a far infrared heating device, or a microwave heating device can be used.

  In the heat treatment according to the present embodiment, for example, after compound A is added to a thin sheet-like fiber material by a method such as impregnation, heating is performed while kneading or stirring the fiber material and compound A with a kneader or the like. Can be adopted. Thereby, it becomes possible to suppress the concentration nonuniformity of the compound A in a fiber raw material, and to introduce | transduce a phosphate group more uniformly to the cellulose fiber surface contained in a fiber raw material. This is because when the water molecules move to the surface of the fiber material with drying, the compound A to be dissolved is attracted to the water molecules by surface tension and similarly moves to the surface of the fiber material (that is, the concentration unevenness of the compound A Is considered to be attributable to the fact that it can be suppressed.

  In addition, the heating device used for the heat treatment is, for example, always the water held by the slurry, and the water produced by the dehydration condensation (phosphorylation) reaction of compound A with the hydroxyl group etc. contained in cellulose etc. It is preferable that it is an apparatus which can be discharged out of the apparatus system. As such a heating device, for example, an air-blowing oven may be mentioned. In addition to being able to suppress the hydrolysis reaction of the phosphate ester bond which is the reverse reaction of phosphoric acid esterification by always draining the water in the device system, it is also possible to suppress the acid hydrolysis of the sugar chain in the fiber. it can. For this reason, it becomes possible to obtain fine fibrous cellulose with a high axial ratio.

  The heat treatment time is, for example, preferably 1 second to 300 minutes after substantial removal of water from the fiber raw material, more preferably 1 second to 1000 seconds, and further preferably 10 seconds to 800 seconds. It is further preferred that In the present embodiment, by setting the heating temperature and the heating time to an appropriate range, the introduction amount of the phosphate group can be set to a preferable range.

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

  The amount of phosphoric acid group introduced into the fiber raw material is, for example, preferably 0.10 mmol / g or more, more preferably 0.20 mmol / g or more, and more preferably 0.50 mmol / g per 1 g (mass) of fine fibrous cellulose. More preferably, it is g or more, and particularly preferably 1.00 mmol / g or more. The amount of phosphoric acid group introduced into the fiber raw material is, for example, preferably 5.20 mmol / g or less, more preferably 3.65 mmol / g or less, per 1 g (mass) of fine fibrous cellulose. It is more preferable that it is 00 mmol / g or less. By making the introduction amount of the phosphate group within the above range, it is possible to facilitate the miniaturization of the fiber raw material and to enhance the stability of the fine fibrous cellulose.

<Carboxyl group introduction process>
In the carboxyl group introducing step, the fiber raw material containing cellulose is oxidized by ozone oxidation, Fenton method, oxidation treatment such as TEMPO oxidation treatment, or a compound having a group derived from carboxylic acid or a derivative thereof, or a group derived from carboxylic acid It is carried out by treatment with an acid anhydride of the compound or a derivative thereof.

  The compound having a carboxylic acid-derived group is not particularly limited, and examples thereof include dicarboxylic acid compounds such as maleic acid, succinic acid, phthalic acid, fumaric acid, glutaric acid, adipic acid, itaconic acid, etc., citric acid, aconitic acid, etc. Tricarboxylic acid compounds are mentioned. The derivative of the compound having a group derived from a carboxylic acid is not particularly limited, and examples thereof include an imidized acid anhydride of a compound having a carboxyl group, and a derivative of an acid anhydride of a compound having a carboxyl group. Although it does not specifically limit as an imide compound of the acid anhydride of the compound which has a carboxyl group, For example, the imide compound of dicarboxylic acid compounds, such as maleimide, a succinimide, phthalimide, is mentioned.

  The acid anhydride of the compound having a group derived from carboxylic acid is not particularly limited, but, for example, dicarboxylic acid compounds such as maleic anhydride, succinic anhydride, phthalic anhydride, glutaric anhydride, adipic anhydride, itaconic anhydride and the like An acid anhydride is mentioned. The derivative of the acid anhydride of the compound having a group derived from a carboxylic acid is not particularly limited, but for example, a compound having a carboxyl group such as dimethylmaleic anhydride, diethylmaleic anhydride, diphenylmaleic anhydride and the like That in which at least a part of hydrogen atoms of the acid anhydride is substituted by a substituent such as an alkyl group or a phenyl group is mentioned.

  When TEMPO oxidation treatment is performed in the carboxyl group introduction step, for example, the treatment is preferably performed under the conditions of pH 6 or more and 8 or less. Such treatment is also referred to as neutral TEMPO oxidation treatment. Neutral TEMPO oxidation treatment is carried out, for example, with sodium phosphate buffer (pH = 6.8), pulp as a fiber material, TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) as a catalyst, etc. It can be carried out by adding a nitroxy radical, sodium hypochlorite as a sacrificial reagent. Furthermore, by coexisting sodium chlorite, aldehyde generated in the process of oxidation can be efficiently oxidized to a carboxyl group.

  The TEMPO oxidation treatment may be carried out under the conditions of pH 10 or more and 11 or less. Such treatment is also referred to as alkaline TEMPO oxidation treatment. The alkaline TEMPO oxidation treatment can be performed, for example, by adding, to a pulp as a fiber raw material, a nitroxy radical such as TEMPO as a catalyst, sodium bromide as a cocatalyst, and sodium hypochlorite as an oxidizing agent .

  The amount of carboxyl group introduced into the fiber raw material varies depending on the type of substituent, but when introducing a carboxyl group by, for example, TEMPO oxidation, preferably 0.10 mmol / g or more per 1 g (mass) of fine fibrous cellulose It is more preferably 0.20 mmol / g or more, still more preferably 0.50 mmol / g or more, and particularly preferably 0.90 mmol / g or more. Further, it is preferably 2.50 mmol / g or less, more preferably 2.20 mmol / g or less, and still more preferably 2.00 mmol / g or less. In addition, when the substituent is a carboxymethyl group, it may be 5.8 mmol / g or less per 1 g (mass) of the fine fibrous cellulose.

<Washing process>
In the method for producing fine fibrous cellulose in the present embodiment, the phosphate-containing fiber can be subjected to a washing step, if necessary. The washing step is performed, for example, by washing the phosphate group-introduced fiber with water or an organic solvent. In addition, the washing step may be performed after each step described later, and the number of times of washing performed in each washing step is not particularly limited.

<Alkali treatment process>
In the case of producing fine fibrous cellulose, an alkali treatment may be performed on the fiber raw material between the phosphoric acid group introduction step and the defibration treatment step described later. Although it does not specifically limit as the method of an alkali treatment, For example, the method of immersing a phosphoric acid group introduction | transduction fiber in an alkali solution is mentioned.

  The alkali compound contained in the alkali solution is not particularly limited, and may be an inorganic alkali compound or an organic alkali compound. In the present embodiment, it is preferable to use, for example, sodium hydroxide or potassium hydroxide as the alkali compound because of high versatility. 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 alcohols, and more preferably an aqueous solvent containing at least water. As the alkali solution, for example, an aqueous solution of sodium hydroxide or an aqueous solution of potassium hydroxide is preferable because of high versatility.

  The temperature of the alkali solution in the alkali treatment step is not particularly limited, but is preferably 5 ° C. or more and 80 ° C. or less, and more preferably 10 ° C. or more and 60 ° C. or less. The immersion time of the phosphate group-introduced fiber in the alkaline solution in the alkali treatment step is not particularly limited, but is preferably 5 minutes to 30 minutes, and more preferably 10 minutes to 20 minutes. The use amount of the alkali solution in the alkali treatment is not particularly limited, but is preferably 100% by mass or more and 100000% by mass or less, for example, 1000% by mass or more and 10000% by mass or less based on the absolute dry mass of the phosphate group-introduced fiber. It is more preferable that

  In order to reduce the amount of alkali solution used in the alkali treatment step, the phosphate group-introduced fiber may be washed with water or an organic solvent after the phosphate 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 phosphate group-introduced fiber subjected to the alkali treatment with water or an organic solvent from the viewpoint of improving the handleability.

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

  Although it does not specifically limit as the method of an acid treatment, For example, the method of immersing a fiber raw material in the acidic liquid containing an acid is mentioned. The concentration of the acidic solution to be used is not particularly limited, but is preferably 10% by mass or less, and more preferably 5% by mass or less. The pH of the acidic solution to be 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 an acid contained in an acidic liquid, an inorganic acid, sulfonic acid, carboxylic acid etc. can be used, for example. Examples of the inorganic acid include sulfuric acid, nitric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, hypochlorous acid, chlorous 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 carboxylic acids 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.

  Although the temperature of the acid solution in acid treatment is not particularly limited, for example, 5 ° C. or more and 100 ° C. or less is preferable, and 20 ° C. or more and 90 ° C. or less is more preferable. Although the immersion time to the acid solution in acid treatment is not particularly limited, for example, 5 minutes or more and 120 minutes or less are preferable, and 10 minutes or more and 60 minutes or less are more preferable. The use amount of the acid solution in the acid treatment is not particularly limited, but preferably 100% by mass or more and 100000% by mass or less, and more preferably 1000% by mass or more and 10000% by mass or less based on the absolute dry mass of the fiber material. Is more preferred.

<Disintegration processing>
A fine fibrous cellulose can be obtained by subjecting the phosphate group-introduced fiber to disaggregation treatment in a defibration treatment step. In the defibration treatment step, for example, a defibration treatment device can be used. The fibrillation treatment apparatus is not particularly limited, but for example, a high-speed fibrillation machine, a grinder (stone mill type crusher), a high pressure homogenizer or an ultrahigh pressure homogenizer, a high pressure collision type crusher, a ball mill, a bead mill, a bead mill, a disc type refiner, a conical refiner, biaxial A kneader, a vibration mill, a homomixer under high speed rotation, an ultrasonic dispersion machine, or a beater can be used. Among the above-mentioned fibrillation treatment apparatus, it is more preferable to use a high-speed fibrillation machine, a high pressure homogenizer, or an ultrahigh pressure homogenizer which is less affected by the grinding media and less likely to contaminate.

  In the defibration treatment step, for example, it is preferable to dilute the phosphate 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, non-proton 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 and glycerin. Examples of ketones include acetone, methyl ethyl ketone (MEK) and the like. Examples of the 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 and butyl acetate. Examples of the aprotic polar solvent include dimethylsulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMAc), and N-methyl-2-pyrrolidinone (NMP).

  The solid content concentration of the fine fibrous cellulose at the time of the defibration treatment can be set appropriately. In addition, in the slurry obtained by dispersing the phosphate group-introduced fiber in a dispersion medium, solid content other than the phosphate group-introduced fiber such as urea having hydrogen bonding property may be contained.

<Production process of absorption layer>
It is preferable that the manufacturing process of an absorption layer includes the process of mixing the dispersion liquid of fine fibrous cellulose, and a resin solution, and obtaining a liquid mixture. The type of dispersion of fine fibrous cellulose and the type of dispersion medium in the resin solution are not particularly limited, and examples thereof include water, an organic solvent, and a mixture of water and an organic solvent. Among them, the solvent is preferably water.

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

  In the case of forming a sheet to be an absorbent layer from a mixture of fine fibrous cellulose and a resin, the process includes a coating step of coating the mixture on a substrate or a paper making step of making the mixture.

<< Coating process >>
In the coating step, a sheet can be obtained, for example, by applying a mixed liquid (slurry) onto a substrate and drying it to peel the formed sheet from the substrate. Moreover, a sheet can be continuously produced by using a coating device and a long base material.

  The material of the substrate used in the coating step is not particularly limited, but a material having high wettability to the slurry may be capable of suppressing shrinkage of the sheet during drying, but the sheet formed after drying is easier. It is preferable to select one that can be peeled off. Among them, a resin film or plate or a metal film or plate is preferable, but is not particularly limited. For example, films or sheets of resins such as acrylic, polyethylene terephthalate, vinyl chloride, polystyrene, polyvinylidene chloride, etc., films, sheets of metals of aluminum, zinc, copper, iron, and those surfaces of which are oxidized, stainless steel A plate, a brass film or plate can be used.

  In the coating process, when the viscosity of the slurry is low and the slurry develops on the substrate, a frame for blocking is fixed on the substrate and used to obtain a sheet of a predetermined thickness and basis weight. May be The frame for blocking is not particularly limited, but it is preferable to select, for example, one that can easily peel off the end of the sheet that adheres after drying. From such a viewpoint, one obtained by molding a resin plate or a metal plate is more preferable. In this embodiment, for example, resin plates such as acrylic plates, polyethylene terephthalate plates, vinyl chloride plates, polystyrene plates, polyvinylidene chloride plates, etc., metal plates such as aluminum plates, zinc plates, copper plates, iron plates, etc. It is possible to use one which has been subjected to oxidation treatment, a stainless steel plate, a brass plate or the like.

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

In the coating step, 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, more preferably 20 g / m ² or more and 150 g / m ² or less It is preferable to apply to a material. By coating so that a basis weight may become in the said range, the sheet | seat excellent in intensity | strength is obtained.

  The coating step includes the step of drying the slurry coated on the substrate as described above. The step of drying the slurry is not particularly limited, but may be performed by, for example, a non-contact drying method, a method of drying while constraining the sheet, or a combination thereof. The non-contact drying method is not particularly limited, but 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 by infrared light, far infrared light or near infrared light is not particularly limited, but can be performed using, for example, an infrared light device, a far infrared light device or a near infrared light device. The heating temperature in the heating and drying method is not particularly limited, but is preferably, for example, 20 ° C. or more and 150 ° C. or less, and more preferably 25 ° C. or more and 105 ° C. or less. When the heating temperature is set to the above lower limit value or more, the dispersion medium can be volatilized quickly. Moreover, if heating temperature is below the said upper limit, suppression of the cost which a heating requires, and suppression of the discoloration by the heat of fibrous cellulose are realizable.

<< papermaking process >>
The paper making 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 long mesh type, circular net type and inclined type, or a multilayer paper making machine combining these. In the paper making process, known paper making methods such as hand paper making may be employed.

  The paper making process is performed by filtering and dewatering the slurry with a wire to obtain a wet paper sheet, and pressing and drying this sheet. The filter cloth used when filtering and dewatering the slurry is not particularly limited, but it is more preferable that, for example, fibrous cellulose does not pass 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, and a porous membrane are preferable. The organic polymer is not particularly limited, but non-cellulose-based organic polymers such as polyethylene terephthalate, polyethylene, polypropylene, polytetrafluoroethylene (PTFE) and the like are preferable. In this embodiment, for example, a porous film of polytetrafluoroethylene having a pore diameter of 0.1 μm to 20 μm, a woven fabric of polyethylene terephthalate or polyethylene having a pore diameter of 0.1 μm to 20 μm, and the like can be mentioned.

  In the sheet forming process, a method of producing a sheet from the slurry is, for example, discharging the slurry onto the top surface of the endless belt, squeezing the dispersion medium from the discharged slurry to form a web, and drying the web. And a drying section for producing a sheet. An endless belt is disposed from the water squeezing section to the drying section, and the web generated in the water squeezing section is conveyed to the drying section while being placed on the endless belt.

  The dewatering method used in the papermaking process is not particularly limited, and examples thereof include the dewatering method commonly used in the production of paper. Among these, a method of dewatering with a long mesh, circular net, inclined wire or the like and then dewatering with a roll press is preferable. Further, the drying method used in the paper making process is not particularly limited, and for example, the method used in the production of paper may be mentioned. Among these, a drying method using a cylinder drier, a Yankee drier, hot air drying, a near infrared heater, an infrared heater or the like is more preferable.

(Adhesive layer)
The absorbent 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 absorbent layer 30 and the base material layer 20. In this case, as shown in FIG. 6, an adhesive layer 25 is preferably provided between the absorbing layer 30 and the base layer 20. That is, the absorbing layer 30 may be laminated to the base material layer 20 via the adhesive layer 25. In FIG. 6, the layer configurations of the base layer 20, the adhesive layer 25 and the absorption layer 30 are drawn for easy understanding, so the thickness and thickness ratio of each layer are not necessarily the same as the actual container configuration. Absent.

  As an adhesive agent which comprises a contact bonding layer, acrylic resin can be mentioned, for example. Moreover, as adhesives other than acrylic resin, for example, vinyl chloride resin, (meth) acrylic acid ester resin, styrene / acrylic acid ester copolymer resin, vinyl acetate resin, vinyl acetate / (meth) acrylic resin 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. Rubber-based emulsions and the like.

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

(Transmissive layer)
A permeable layer 40 may be further provided on the outer surface side of the absorbing layer 30. As shown in FIG. 7, the transmission layer 40 is disposed 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 may be provided between each layer. It is also good. That is, in the container 100, the base material layer 20, the adhesive layer, the absorbent layer 30, the adhesive layer, and the permeable layer 40 may be laminated in this order from the inner surface side. In FIG. 7, the layer configurations of the base layer 20, the absorption layer 30, and the transmission layer 40 are drawn for easy understanding, so the thickness and thickness ratio of each layer are not necessarily the same as the actual container configuration. Absent.

  The permeable layer is a layer capable of transmitting moisture. Since the permeable layer can permeate moisture, it does not reduce the water absorption rate in the absorbing layer. In addition, the permeable layer serves to enhance the design of the container and to enhance the feeling of use of the container. For example, when a layer containing pulp is employed as the permeable layer, it is possible to suppress the feeling of stickiness on the surface of the container, and to enhance the refreshing feeling of the user's handle portion.

  The permeable layer is preferably a layer containing at least one selected from pulp and resin. Among them, the permeable layer is more preferably a layer containing pulp, and for example, the permeable layer is preferably paper. When the transmission layer is made of resin or the like, pores may be provided in the sheet to be the transmission layer in order to improve the water permeability of the transmission layer. Thus, a permeable layer having pores is also preferably used.

  The thickness of the transmission layer is not particularly limited, but is preferably 10 μm or more, more preferably 50 μm or more, still more preferably 100 μm or more, and the thickness of the transmission layer is It is preferable that it is 5000 micrometers or less.

  A printing layer may be provided on at least one of the inner surface side and the outer surface side of the transmissive layer. For example, characters, patterns, etc. may be printed on the outer surface of the transmission layer. The printing layer is provided by a known method in accordance with the material of the outer surface of the transmission layer.

(Method of manufacturing container)
It is preferable that the manufacturing process of a container contains either of the following (a) processes or (b) processes.
Step (a): A laminated sheet comprising a base material layer and an absorbent layer is obtained, and the laminated sheet is formed into a container shape.
(B) Step: After the base material layer is formed into a container shape, an absorbent layer is provided on the outer peripheral surface of the base material layer.
In the container manufacturing process, as described above, after the sheet to be the absorbent layer is prepared in advance, the sheet may be overlaid on the substrate layer, and a slurry for absorbent layer formation is coated on the substrate layer. The absorbent layer may be formed by drying. When the slurry for absorbent layer formation is coated on a base material layer and it makes it dry, you may employ | adopt the conditions similar to << coating process >> mentioned above.

  Before forming the laminate sheet into a container shape in the (a) step, or before forming the base material layer into a container shape in the (b) step, each sheet member is cut into a desired shape. When molding into a container shape, for example, molding can be performed 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 (a) step or when providing the absorbing layer on the outer peripheral surface of the base layer in the (b) step, for example, an adhesive is applied to the absorbing layer, and this coated surface is used as the base layer Can be bonded to the outer peripheral surface side of In this case, a UV curable adhesive may be used as the adhesive. In the case of using a UV-curable adhesive, after bonding the absorbing layer to the base material layer through the adhesive layer, the absorbing layer and the base material layer can be firmly bonded by irradiating ultraviolet rays from the absorbing layer side. it can.

  In addition, when an adhesive is not used when obtaining a laminated sheet in the (a) step, or when providing the absorbent layer on the outer peripheral surface of the base layer in the (b) step, the absorbent layer is immersed in water and then the substrate You may bond together to the outer peripheral surface side of a layer, and the slurry which forms an absorption layer may be coated on the outer peripheral surface of a base material layer, and an absorption layer may be formed by making it dry.

  The present invention will be more specifically described by the following examples, but the scope of the present invention is not limited by the following examples.

Example 1
[Preparation of phosphorylated pulp]
Softwood kraft pulp manufactured by Oji Paper Co., Ltd. (solid content 93% by mass, basis weight 208 g / m ^{2 in} sheet form, Canadian standard freeness (CSF) of 700 ml measured according to JIS P 8121) It was used.

  The raw material pulp was subjected to a phosphorylation treatment as follows. First, a mixed aqueous solution of ammonium dihydrogen phosphate and urea is added to 100 parts by mass (dry mass) of the above-mentioned raw material pulp to make 45 parts by mass of ammonium dihydrogen phosphate, 120 parts by mass of urea, 150 parts by mass of water The solution was adjusted to obtain a chemical solution impregnated pulp. Next, the chemical-impregnated pulp obtained was heated for 200 seconds with a hot air drier at 165 ° C. to introduce a phosphoric acid group to the cellulose in the pulp to obtain a phosphorylated pulp.

  Next, the resulting phosphorylated pulp was subjected to a washing treatment. The washing process is performed by repeating the operation of filtering and dewatering the pulp dispersion obtained by pouring 10 L of ion-exchanged water with respect to 100 g (absolute dry mass) of phosphorylated pulp so that the pulp can be uniformly dispersed. went. When the electric conductivity of the filtrate became 100 μS / cm or less, it was regarded as the washing end point.

  Next, neutralization treatment was performed on the washed phosphorylated pulp as follows. First, after diluting the phosphorylated pulp after washing with 10 L of ion exchanged water, a phosphated pulp slurry having a pH of 12 or more and 13 or less was obtained by gradually adding 1N aqueous sodium hydroxide solution while stirring. . Next, the phosphorylated pulp slurry was dewatered to obtain a phosphorylated pulp subjected to neutralization treatment. Next, the above-mentioned washing treatment was performed on the phosphorylated pulp after the neutralization treatment.

The infrared absorption spectrum of the phosphorylated pulp thus obtained was measured using FT-IR. As a result, absorption attributable to phosphate groups was observed at around 1230 cm ^-1 , confirming that phosphate groups were added to the pulp. Moreover, when the obtained phosphorylated pulp was tested and analyzed by an X-ray diffractometer, it was found at two positions of 2θ = 14 ° or more and 17 ° or less and 2θ = 22 or more and 23 ° or less A typical peak was confirmed and confirmed to have cellulose type I crystals.

[Fiber opening treatment]
Ion-exchanged water was added to the obtained phosphorylated pulp to prepare a slurry having a solid content concentration of 2% by mass. This slurry was treated twice at a pressure of 200 MPa with a wet atomization device (Starburst, manufactured by Sugino Machine Co., Ltd.) to obtain a fine fibrous cellulose dispersion A containing fine fibrous cellulose. It was confirmed by X-ray diffraction that this fine fibrous cellulose maintained cellulose type I crystals. Moreover, it was 3-5 nm when the fiber width of fine fibrous cellulose was measured using the transmission electron microscope. In addition, the amount of phosphate groups (the amount of strongly acidic groups) measured by the measurement method described later was 1.45 mmol / g.

[Dissolution of polyvinyl alcohol]
Polyvinyl alcohol (Kuraray Co., Ltd., POVAL 105, degree of polymerization: 500, degree of saponification: 98 to 99 mol%) was added to ion-exchanged water to 20% by mass, stirred at 95 ° C. for 1 hour, and dissolved . 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 polyvinyl alcohol aqueous solution were each diluted with ion exchanged water so that the solid content concentration was 0.6 mass%. Subsequently, with respect to 10 mass parts of fine fiber-like cellulose dispersion liquids after dilution, it mixed so that the polyvinyl alcohol aqueous solution after dilution might be 90 mass parts, and the liquid mixture A was obtained. Furthermore, 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. In addition, a frame (inner size: 180 mm × 180 mm, height: 50 mm) was placed on the acrylic plate so as to obtain a predetermined basis weight. Then, it dried by 70 degreeC dryer for 24 hours, and obtained the fine fibrous cellulose containing sheet A used as 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 (made of a cylindrical body member and a bottom member, a paper cup having an opening diameter of 70.5 mm and a total height of 67.5 mm) having an inner surface laminated with polyethylene was prepared. The fine fibrous cellulose-containing sheet A was cut so as to cover the outer peripheral surface up to 75% of the total height from the bottom of the paper cup (the cut shape becomes a truncated cone). Next, a UV curable acrylic resin adhesive (Z-587-16, manufactured by Aika Kogyo Co., Ltd.) was applied to one surface of the fine fibrous cellulose-containing sheet A after cutting using a paint brush. The fine fibrous cellulose-containing sheet A was bonded to a 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 short arcs of the fine fibrous cellulose-containing sheet A were pasted so that the bottom sides of the body members of the paper cups coincide with each other. Furthermore, with this paper cup being turned sideways, it passes through a UV conveyor apparatus (ECS-4011GX, manufactured by Eye Graphics Co., Ltd.) set to an ultraviolet radiation dose of 200 mJ / cm ² to cure the UV curable acrylic resin adhesive I did. Furthermore, after rotating the paper cup 90 degrees around a line connecting the center point of the bottom and the center point of the opening in a state where the paper cup is turned sideways, the process of passing it through a UV conveyor device is performed three times. The acrylic resin adhesive was cured. According to the above-described procedure, a container was formed having a base layer containing paper and polyethylene, an adhesive layer containing acrylic resin, and an absorbent layer containing fine fibrous cellulose.

Example 2
[Dissolution of polyethylene oxide]
Polyethylene oxide (PEO-18, manufactured by Sumitomo Seika Chemicals Co., Ltd.) was added to ion-exchanged water so as to be 1% by mass, and dissolved by stirring for 1 hour. 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 exchange water so that the solid content concentration was 0.6 mass%. Subsequently, with respect to 100 mass parts of fine fiber-like cellulose dispersion liquids after dilution, it mixed so that the polyethylene oxide aqueous solution after dilution might be 20 mass parts, and the liquid mixture B was obtained. Furthermore, the liquid mixture 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. In addition, a frame (inner size: 180 mm × 180 mm, height: 50 mm) was placed on the acrylic plate so as to obtain a predetermined basis weight. Then, it dried by 70 degreeC dryer for 24 hours, and obtained the fine fibrous cellulose containing sheet B used as an absorption layer later. The thickness of the fine fibrous cellulose-containing sheet B was 50 μm.

[Formation of container]
A base material layer, an adhesive layer, and an absorption layer were provided in the same manner as [Formation of container] in 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 container was formed.

[Example 3]
A base layer was prepared in the same manner as in Example 1 except that fine fibrous cellulose dispersion B was used instead of fine fibrous cellulose dispersion A in [Preparation of fine fibrous cellulose-containing sheet] in Example 1. A container was formed with an adhesive layer and an absorbent layer. The finely fibrous cellulose dispersion B was prepared by the following procedure.
Softwood kraft pulp manufactured by Oji Paper Co., Ltd. (solid content 93% by mass, basis weight 208 g / m ^{2 in} sheet form, Canadian standard freeness (CSF) of 700 ml measured according to JIS P 8121) It was used. This pulp was beaten in a double disc refiner until the anomalous freeness was 100 ml, to obtain a pulp dispersion having a concentration of 2% by mass. This pulp dispersion is diluted with ion-exchanged water to a concentration of 0.7% by mass, and subjected to three times of refinement treatment at a treatment pressure of 120 MPa with a high pressure homogenizer "Panda Plus 2000" manufactured by NiroSoavi, and fine fibrous cellulose Dispersion B was obtained. It was confirmed by X-ray diffraction that this fine fibrous cellulose maintained cellulose type I crystals. Moreover, it was 130 nm when the fiber width of the fine fibrous cellulose was measured using a transmission electron microscope.

Example 4
A base material layer was prepared in the same manner as in Example 1 except that fine fibrous cellulose dispersion C was used instead of fine fibrous cellulose dispersion A in [Preparation of fine fibrous cellulose-containing sheet] in Example 1. A container was formed with an adhesive layer and an absorbent layer. The finely fibrous cellulose dispersion C was prepared by the following procedure.

[Preparation of TEMPO oxidized pulp]
Softwood kraft pulp (undried) (solid content 93% by mass, basis weight 208 g / m ^{2 in} sheet form) manufactured as Oji Paper Co., Ltd. as raw material pulp, Canadian Standard Freeness Measured according to JIS P 8121 ) Used 700 ml). The raw material pulp was subjected to alkaline TEMPO oxidation treatment as follows. First, the above raw material pulp equivalent to a dry mass of 100 parts by mass, 1.6 parts by mass of TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl), 10 parts by mass of sodium bromide, 10000 parts of water It was dispersed in the department. Then, 13 mass% sodium hypochlorite aqueous solution was added so that it might be set to 3.8 mmol with respect to 1.0 g of pulps, and reaction was started. During the reaction, 0.5 M aqueous sodium hydroxide solution was added dropwise to keep the pH at 10 or more and 10.5 or less, and when no change was observed in the pH, the reaction was regarded as complete.

  Next, the obtained TEMPO oxidized pulp was washed. Washing is performed by dewatering the pulp slurry after TEMPO oxidation to obtain a dewatered sheet, pouring 5000 parts by mass of ion exchanged water, stirring and uniformly dispersing, and then repeating the operation of filtering and dewatering. The When the electric conductivity of the filtrate became 100 μS / cm or less, it was regarded as the washing end point.

The TEMPO oxidized pulp thus obtained was tested and analyzed by an X-ray diffractometer. It was found at two positions of 2θ = 14 ° or more and 17 ° or less and 2θ = 22 or more and 23 ° or less A typical peak was confirmed and confirmed to have cellulose type I crystals.

[Fiber opening treatment]
Ion-exchanged water was added to the obtained TEMPO oxidized pulp to prepare a slurry having a solid content concentration of 2% by mass. This slurry was treated six times at a pressure of 200 MPa with a wet atomization apparatus (Starburst, manufactured by Sugino Machine Co., Ltd.) to obtain a fine fibrous cellulose dispersion C containing fine fibrous cellulose. It was confirmed by X-ray diffraction that this fine fibrous cellulose maintained cellulose type I crystals. Moreover, it was 3-5 nm when the fiber width of the fine fibrous cellulose was measured using the transmission electron microscope. In addition, the amount of carboxyl groups measured by the measuring method mentioned later was 1.30 mmol / g.

[Example 5]
In [Formation of container] in Example 1, a commercially available polystyrene cup (made of a cylindrical body member and a bottom member, having an opening diameter of 70.0 mm and a height of 68.6 mm) instead of a paper cup A container provided with a base 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 for using.

[Example 6]
In [Formation of container] in Example 2, instead of a paper cup, a commercially available polystyrene cup (made of a cylindrical body member and a bottom member, an opening diameter of 70.0 mm, a height of 68.6 mm) A container having a base 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 2 except that the above was used.

[Example 7]
In [Formation of Container] in Example 3, a commercially available polystyrene cup (made of a cylindrical body member and a bottom member, having an opening diameter of 70.0 mm and a height of 68.6 mm) instead of a paper cup A container having a base 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 3 except for using.

[Example 8]
The packaging paper (Oji F-TEX Co., Ltd., Grafan; thickness 30 μm) was cut into the same shape as the fine fibrous cellulose-containing sheet A cut in [Formation of container] in Example 1. The packaging paper was immersed in ion-exchanged water for 10 seconds, wound around so as to overlap the portion of the container obtained in Example 1 in which the fine fibrous cellulose-containing sheet A was present, and allowed to stand. Furthermore, the paper cup was dried with a dryer at 50 ° C. for 24 hours with the bottom facing up. According to the above-described procedure, a container provided with a base layer containing paper and polyethylene, an adhesive layer containing acrylic resin, an absorption layer containing fine fibrous cellulose, and a paper permeable layer was formed.

[Example 9]
In [Formation of Container] of Example 1, a container was formed in the following procedure without using an acrylic resin adhesive.
A commercially available paper cup (made of a cylindrical body member and a bottom member, a paper cup having an opening diameter of 70.5 mm and a total height of 67.5 mm) having an inner surface laminated with polyethylene was prepared. The fine fibrous cellulose-containing sheet A was cut so as to cover the outer peripheral surface up to 75% of the total height from the bottom of the paper cup (the cut shape becomes a truncated cone). Subsequently, the fine fibrous cellulose-containing sheet A after cutting was immersed in ion exchange water for 10 seconds. The fine fibrous cellulose-containing sheet A was bonded to a paper cup. At this time, the short arcs of the fine fibrous cellulose-containing sheet A were pasted so that the bottom sides of the body members of the paper cups coincide with each other. Furthermore, the paper cup was dried with a dryer at 50 ° C. for 24 hours with the bottom facing up. According to the above procedure, a container was formed with a base layer comprising paper and polyethylene, and an absorbent layer comprising fine fibrous cellulose.

[Example 10]
In [Production of fine fibrous cellulose-containing sheet] of Example 1, the mixed liquid A was weighed so that the finished basis weight of the sheet would be 18 g / m ² , and then developed on a commercially available transparent acrylic plate. In the same manner as in Example 1, a container was formed with a base layer containing paper and polyethylene, an adhesive layer containing acrylic resin, and an absorbent layer containing fine fibrous cellulose. Here, the thickness of the fine fibrous cellulose-containing sheet was 15 μm.

Comparative Example 1
In Example 1, bonding of the fine fibrous cellulose-containing sheet A was not performed, and a container having only a base layer containing paper and polyethylene was prepared, and was subjected to measurement and evaluation described later.

Comparative Example 2
In [Production of Fine Fibrous Cellulose-Containing Sheet] of Example 1, a sheet composed only of polyvinyl alcohol was produced without mixing the fine fibrous cellulose dispersion A. Here, the thickness of the sheet was 50 μm. The other procedures were the same as in Example 1 to form a container provided with a substrate layer containing paper and polyethylene, an adhesive layer containing an acrylic resin, and an absorbent layer containing polyvinyl alcohol.

Comparative Example 3
In [Production of Fine Fibrous Cellulose-Containing Sheet] of Example 2, a sheet composed only of polyethylene oxide was produced without mixing the fine fibrous cellulose dispersion A. In addition, 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. The other procedures were the same as in Example 2 to form a container provided with a substrate layer containing paper and polyethylene, an adhesive layer containing an acrylic resin, and an absorbent layer containing polyethylene oxide.

Comparative Example 4
In Example 5, bonding of the fine fibrous cellulose-containing sheet A was not performed, and a container provided with only a base material layer made of polystyrene was prepared and used for measurement and evaluation described later.

Comparative Example 5
In [Production of Fine Fibrous Cellulose-Containing Sheet] of Example 5, a sheet composed only of polyvinyl alcohol was produced without mixing the fine fibrous cellulose dispersion A. Here, the thickness of the sheet was 50 μm. The other procedures were the same as in Example 5 to form a container provided with a substrate layer containing polystyrene, an adhesive layer containing an acrylic resin, and an absorbent layer containing polyvinyl alcohol.

Comparative Example 6
In [Production of Fine Fibrous Cellulose-Containing Sheet] of Example 6, a sheet composed of only polyethylene oxide was produced without mixing the fine fibrous cellulose dispersion A. In addition, 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. The other procedures were the same as in Example 6 to form a container provided with a substrate 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 packaging paper (manufactured by Oji F-TEX, Inc., Grafan; thickness 30 μm) was used instead of the fine fibrous cellulose-containing sheet A. The other procedures were the same as in Example 1 to form a container provided with a substrate layer containing paper and polyethylene, an adhesive layer containing an acrylic resin, and a paper permeable layer.

[Measurement]
[Fiber width]
The fiber width of the fine fibrous cellulose was measured by the following method. The supernatant liquid of the above-mentioned fine fibrous cellulose dispersion obtained by treatment with a wet atomization device is treated with water so that the concentration of fine fibrous cellulose is 0.01% by mass or more and 0.1% by mass or less The solution was dropped on a diluted and hydrophilized carbon grid film. After drying, it was stained with uranyl acetate and observed with a transmission electron microscope (JEOL-2000EX manufactured by JEOL Ltd.).

[Phosphoric acid group content]
The phosphoric acid group content of the fine fibrous cellulose is prepared by diluting the fine fibrous cellulose dispersion containing the fine fibrous cellulose to be treated with ion exchanged water so that the content is 0.2% by mass. The cellulose-containing slurry was treated with an ion exchange resin and then measured by titration with an alkali. The treatment with ion exchange resin is carried out by adding 1/10 strongly acidic ion exchange resin (Amberjet 1024; Organo Corporation, conditioned) to the above fibrous cellulose-containing slurry and shaking it for 1 hour It was carried out by pouring on a mesh of 90 μm mesh to separate resin and slurry.
In addition, titration using an alkali is carried out by adding an aqueous solution of 0.1 N sodium hydroxide to the fibrous cellulose-containing slurry after treatment with an ion exchange resin, while adding 50 μL each once for every 30 seconds. This was done by measuring the change in the value of. The amount of phosphate group (mmol / g) is obtained by dividing the amount of alkali (mmol) required in the region corresponding to the first region shown in FIG. 4 among the measurement results by the solid content (g) in the slurry to be titrated. Calculated.

[Carboxyl group content]
The carboxyl group content of the fine fibrous cellulose is prepared by diluting the fine fibrous cellulose dispersion containing the fine fibrous cellulose to be treated with ion exchange water so that the content becomes 0.2% by mass. After the treatment with the ion exchange resin was performed on the contained slurry, it was measured by performing titration using an alkali.
The treatment with ion exchange resin is carried out by adding 1/10 strongly acidic ion exchange resin (Amberjet 1024; Organo Corporation, conditioned) to the above fibrous cellulose-containing slurry and shaking it for 1 hour It was carried out by pouring on a mesh of 90 μm mesh to separate resin and slurry.
In addition, titration using an alkali is carried out by adding an aqueous solution of 0.1 N sodium hydroxide solution once in 30 seconds to the fibrous cellulose-containing slurry treated with the ion exchange resin, while adding 50 μL of the aqueous solution to the slurry. It did by measuring the change of value. The carboxyl group amount (mmol / g) is obtained by dividing the alkali amount (mmol) required in the region corresponding to the first region shown in FIG. 5 among the measurement results by the solid content (g) in the slurry to be titrated. Calculated.

[Water absorption of container]
A 5 cm square test piece (a piece on which the absorbing layer and the base material layer were laminated) was cut out from the body member of the container obtained in the example and the comparative example. At this time, one end of the test piece was cut out so as to be the bottom of the body member. Next, after measuring the weight W _{A of the} test piece, it was immersed in ion exchange water and held for 24 hours. Thereafter, the test piece was pulled up from ion-exchanged water, and after wiping off the moisture adhering to the surface of the test piece with Kimwipe, the weight W _{B of the} test piece was measured. From the weights W _A and W _B , the water absorption of the container was calculated according to the following equation 1.
Water absorption rate (%) = (W _B- W _A ) / W _A × 100 ... (Equation 1)

[Container's haze]
From the containers obtained in Examples and Comparative Examples, a 5 cm square test piece (a piece on which the absorption layer and the base material layer were laminated) was cut out in the same manner as [Water absorption of container]. About this test piece, the haze by D65 light source was measured according to JISK7136 using the haze meter (Murakami Color Research Laboratory make, HM-150).

[Evaluation]
[Deposition of condensation water]
Ion-exchanged water cooled to 5 ° C. was poured from the bottom of the container to a height of 75% of the total height in the containers obtained in Examples and Comparative Examples, and then allowed to stand in an environment of 28 ° C. and 80% relative humidity for 10 minutes. After standing, the outer peripheral surface up to 75% of the height from the bottom 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 is found in the observation part.
Evaluation 4: The adhesion degree of dew condensation water is clearly less than a general paper cup (comparative example 1 equivalent).
Evaluation 3: The degree of adhesion of dew condensation water is slightly smaller than that of a general paper cup (comparative example 1 equivalent).
Evaluation 2: The adhesion degree of dew condensation water is equivalent to a general paper cup (comparative example 1 equivalent).
Evaluation 1: The adhesion degree of dew condensation water is more than a general paper cup (comparative example 1 equivalent).

[Visibility of contents]
The blue aqueous dye was diluted to 1% by mass with deionized water and poured from the bottom of the vessel to a height of 75% of the total height. Then, 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 of the contents can be clearly confirmed.
Evaluation 2: Although the blue color of the contents is unclear, it can be confirmed.
Evaluation 1: The blue color shown by the contents can not be confirmed.

  As apparent from the table, in the case of the container of the example provided with the absorption layer containing the fine fibrous cellulose, the adhesion of the condensation water was suppressed to the container obtained in the comparative example. In the containers of Examples 5 to 7 in which polystyrene was used as the base material layer and the absorbent layer containing fine fibrous cellulose was provided, the visibility of the contents was also good. Moreover, the container of Example 8 provided with the permeation | transmission layer had a favorable usability | use_condition.

Reference Signs List 20 base material layer 25 adhesive layer 30 absorption layer 40 transmission layer 100 container

Claims (13)

A substrate layer and an absorption layer,
The absorption layer contains fibrous cellulose having a fiber width of 1000 nm or less,
The container in which the absorption layer is disposed on the outer surface side of the base material layer. Comprising a body member and a bottom member,
The container according to claim 1, wherein the body member comprises the base material layer and the absorbent layer.   The container according to claim 1, wherein the base material layer contains at least one selected from pulp, resin, glass and metal.   The container according to any one of claims 1 to 3, wherein the absorption layer contains fibrous cellulose having a fiber width of 1000 nm or less and a hydrophilic polymer.   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 fibrous cellulose is a fibrous cellulose having a phosphoric acid group or a substituent derived from a phosphoric acid group.   The thickness of the said absorption layer is 10 micrometers or more, The container of any one of Claims 1-6. The container according to any one of claims 1 to 7, wherein the water absorption coefficient 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 rate (%) = (W _B −W _A ) / W _A × 100
Here, W _B represents the weight of the area (X) after being immersed in ion exchange water for 24 hours, and W _A represents the weight of the area (X) before being immersed in ion exchange water.   The container according to any one of claims 1 to 8, 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 9, wherein the absorption layer is laminated to the base material layer via an adhesive layer. Furthermore, it has a permeable layer,
The container according to any one of claims 1 to 10, wherein the permeable layer is disposed on the outer surface side of the absorbent layer.   The container according to any one of claims 1 to 11, wherein a part of the base material layer is exposed to the outer surface.   The container according to any one of claims 1 to 12, for containing cold articles.

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