JPH02253846A - Functional water absorbing sheet - Google Patents

Abstract

PURPOSE:To form a water absorbing sheet having a specified function by holding a highly water absorbing material, etc., between a packing material and a water impermeable packing material in one body and further holding a highly water absorbing material, etc., between the resulting sandwich and a packing material. CONSTITUTION:A mixture 21 contg. a highly water absorbing material and/or a specified functional material is held between a packing material 1 and a water impermeable packing material 3 in one body. A mixture 22 contg. a highly water absorbing material and/or a specified functional material is further held between the resulting sandwich and a packing material 2 in one body to form a functional water absorbing sheet having a multilayered structure including layers of the highly water absorbing materials and/or the specified functional materials. Each of the functional materials may have one or more functions such as antibacterial function, deodorizing function and gaseous ethylene adsorbing function.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a functional water-absorbing sheet, and more specifically to a freshness-preserving material for fresh foods, sanitary products,
The present invention relates to a water-absorbing sheet that has specific functions and is useful as a material for products that require high water absorption, such as diapers, disposable rags, and paper towels.

[Conventional technology]

BACKGROUND ART Conventionally, superabsorbent resins have been widely used as materials for preserving the freshness of fresh foods, sanitary products, diapers, disposable rags, paper towels, and the like.

Conventionally, various measures have been taken to maintain the freshness of fresh foods, but in particular, free water that exudes from fresh foods such as meat and fish and shellfish can significantly reduce the freshness of the foods concerned. Therefore, immediate removal of the free water is an important factor indispensable for maintaining freshness.

Conventionally, as a countermeasure against this free water, a method is known as a prior art in which a water absorbent sheet using a super absorbent polymer material is housed in the packaging form of fresh food to absorb and remove the free water.

In addition, freshness of fruits and vegetables decreases due to ethylene gas generated from the fruits and vegetables and condensation of water vapor due to respiration when they are packed in boxes, bags, etc. in closed or nearly sealed conditions.

In order to prevent such deterioration in the freshness of fruits and vegetables, conventionally, two types of freshness-preserving materials, for example, a water-absorbing sheet made of super absorbent resin and an ethylene gas adsorbent, have been used to transport fruits and vegetables in boxes or bags. There are known ways to store it.

Water-absorbent sheet products used for various other purposes include, for example, those with a structure in which super-absorbent resin powder is sandwiched between two water-permeable sheet base materials, and super-absorbent resin on the sheet base material surface. Various forms are known, such as those in which a patterned water absorbing layer is provided using a coating agent containing , and an adhesive side layer is formed on the non-patterned part and other sheet base materials are laminated. .

[Problem to be solved by the invention]

However, in the case of the above-mentioned conventional technology, when packaging fruits and vegetables, for example, two types of materials, a water absorbent sheet and an ethylene gas adsorbent, must be individually housed in the packaging form, and a large amount of fresh food is required. There have been various problems, such as extra effort required when packaging, reducing overall work efficiency, and increasing costs.

Furthermore, during transportation, the sachet containing the ethylene gas adsorbent may break and the ethylene gas adsorbent inside may adhere to the surface of the fruits and vegetables, worsening the appearance of the product, or the chemical components of the ethylene gas adsorbent may damage the food. There was a risk of contamination.

Packaging bodies for ordinary fresh foods use ordinary packaging materials, and the packaging materials themselves do not have specific functions such as antibacterial properties, so there is no risk of food deterioration derived from the packaging materials. It is impossible to reliably prevent the deterioration of freshness of fresh foods due to contamination by putrid bacteria using a water-absorbing sheet alone, and it has been desired to establish an effective measure.

In addition, animal foods such as meat and fish and shellfish are generally stored and distributed under refrigerated conditions, but at this time, the structure of the food generates a unique odor in addition to dripping, and this odor significantly reduces the product value. It was causing this. In particular, when frozen at -degrees and thawed, the tissue itself is destroyed, resulting in a significant odor, and there has been a strong desire to establish effective measures to prevent or eliminate this odor.

Products other than the above fresh foods, such as sanitary products, diapers,
For products that require high water absorption, such as disposable rags and paper towels, there are still insufficient effective measures in terms of water absorption, prevention of bacterial contamination, deodorization, etc.
In addition to water absorption, there was a desire to develop a new product with specific functions that could solve these problems.

Further, conventional water-absorbing sheets have a problem in that the absorbed moisture permeates into the back surface of the water-absorbing sheet, making it difficult to handle.

Furthermore, even when a highly absorbent material is combined with a specific functional material, some of the functional materials are sensitive to water, and their functionality may deteriorate or be inactivated by absorbed moisture. There is something. Therefore, there is a problem in that the combinations of such materials are also limited.

Under these circumstances, the inventors of the present invention have conducted extensive research in order to solve the problems of the above-mentioned conventional technology. As a result, the present inventors have combined a super absorbent material and a specific functional material with a specific packaging material. Furthermore, the inventors have discovered that the above problems can be solved by constructing a water absorbent sheet that has both water absorbency and a specific function in such a way that the two do not affect each other, leading to the completion of the present invention. Ta.

That is, an object of the present invention is to provide a novel water-absorbing sheet that has high water-absorbing properties, specific functions, and waterproof properties, and has functionality that is useful as a freshness-keeping material for fresh foods.

[Means to solve the problem]

The structure of the present invention adopted to achieve such an object is to sandwich a mixture of a super absorbent polymer material and a specific functionality between specific packaging materials to form a sheet-like product. It is characterized by configuring, specifically,
They are as follows.

(1) A mixture (21) containing a super absorbent material and/or a specific functional material is sandwiched and integrated between a packaging material (1) and a non-water permeable packaging material (3), and the sandwiched body and packaging materials (
A mixture (22) containing a super absorbent material and/or a specific functional material is sandwiched and integrated between 2) to create a multilayer structure including a layer of a super absorbent material and a layer of a specific functional material. A water-absorbing sheet with functionality characterized by:

(2) The functional water-absorbing sheet described in (1) above, wherein the specific functional material is a material having one or more specific functions such as antibacterial properties, deodorizing properties, or ethylene gas adsorption properties.

(3) The water-absorbing sheet having the functionality described in (1) above, wherein the mixture contains a binder made of a thermoplastic resin.

(4) A water-absorbing sheet having the functionality described in (1) above, characterized in that the entire body is integrally sandwiched by heated embossing rolls.

Next, the present invention will be explained in detail based on the drawings.

FIG. 1 shows an embodiment of the present invention, in which a mixture (21) containing a highly water-absorbent material is sandwiched and integrated between a packaging material (1) and a non-water permeable packaging material (3). A mixture (22) containing a specific functional material is sandwiched and integrated between the sandwiched body and the packaging material (2) to form a super absorbent material layer (21) and a specific functional material. FIG. 2 is a cross-sectional view of a functional water-absorbing sheet having a multilayer structure including a layer (22) of a flexible material. FIG. 2 shows another example in which a laminate is used as the packaging materials (1) and (2).

The non-water permeable packaging material (3) is a plastic film made of thermoplastic resin, paper treated with non-water permeable processing such as polyethylene coated paper, or an appropriate base material such as nonwoven fabric, other paper, or thermoplastic resin film. A laminate, etc., laminated with a laminate or the like is preferably used.

In addition, the packaging materials (1) and (2) may be, for example, sizeless paper, nonwoven fabric, water-permeable porous sheets such as hydrophilic polyethylene or polypropylene, cellophane, vinylon film, or thermoplastic film with fine communication holes formed during film production. Papers that have a certain degree of water permeability, such as those that have been foamed to have a nucleation agent, those that have been stretched with the addition of an inorganic substance or a high-melting point nucleating agent to form microscopic pores, and other papers that are made of a mixture of polyethylene, polypropylene, and pulp. The material may be made of any material as long as it has a certain degree of water resistance and strength, and the thickness and degree of lamination are not particularly limited as long as it has a certain degree of water resistance and strength. Preferably, a cellulose membrane is formed using viscose or a cellulose membrane is formed with fine pores.

The nonwoven fabric constituting the laminate is partially or entirely made of thermoplastic resin, such as rayon,
For fibers such as pulp (polyolefin, polyester,
It is preferable to use a nonwoven fabric impregnated with or mixed with a resin such as polyamide, or a nonwoven fabric made of fibers such as polyolefin, polyester, or polyamide.
A basis weight of 15 to 100 g/nfO is suitable.

Further, as the paper, a layer of soft paper such as tissue paper having a basis weight of 15 to 60 g/rrf may be used, but there is no particular limitation.

Among the materials constituting the mixtures (21) and (22), such as highly absorbent materials and specific functional materials, the functional materials include appropriate functions such as antibacterial agents, deodorizing agents, and ethylene gas absorbents, or A substance or composition having an appropriate combination of functions is used.

Antibacterial agents include antibacterial metal materials such as silver, copper, zinc, tin, lead, bismuth, cadmium, chromium, and mercury; -zeolite, activated carbon, silica, activated clay, acid clay, alumina, activated bauxite, It is preferable to use a carrier such as bone charcoal or molecular sieve, but there are no particular limitations on these antibacterial materials, the types of carriers, and the amounts used.

Examples of deodorizing agents include the following.

(1) Physical adsorption deodorizers such as neutral activated carbon, fibrous carbon adsorbent, zeolite, activated alumina, acid clay, etc.

(2) Chemical deodorizer Acidic agents, alkaline agents, oxidizing agents, reducing agents, etc.

(3) Physical/chemical deodorizers such as alkaline or acid impregnated activated carbon, zeolite adsorbed with vegetable essential oils, etc.

(4) Other iron phthalocyanine derivatives, salts with a desulfurization effect such as zinc oxide, mixtures of iron (II) compounds, L-ascorbic acid, and migoban, etc.

In addition to these deodorizing agents, any deodorizing agent may be used as long as it has a deodorizing effect, and one or a mixture of two or more of these deodorizing agents can be used. It is preferable that these deodorizers be mixed with a binder and sandwiched between packaging materials so that each sheet 1 is sandwiched in an amount of 0.1 to 150 g.

As the ethylene gas adsorbent, a carbonaceous molecular sieve adsorbed with bromine, preferably one having 4 to 6 micropores,
Alternatively, acidic water in which sodium bromate or potassium bromate is dissolved may be added to activated carbon and reacted, then dried and pulverized, with a particle size of 5 to 500 IIm. Such ethylene gas adsorbents are desirable because they are not affected by moisture, ie, they do not release adsorbed ethylene gas in the presence of moisture. Generally, activated carbon, zeolite, Oya stone, etc., which are used as ethylene gas adsorbents, are not preferred because they release adsorbed ethylene gas in the presence of moisture.

In addition to these functional materials, materials having appropriate functions can be used, and the types thereof are not particularly limited.

Next, as super absorbent materials, starch/acrylate graft polymers, carboxymethylcellulose crosslinked products, vinyl alcohol/acrylate copolymers, polyacrylonitrile hydrolysates, crosslinked polyacrylates, modified polyvinyl alcohols, etc. Examples include acrylic acid polymer, acrylate/acrylamide copolymer, isobutylene/maleic anhydride copolymer, etc., but any other material having high water absorption may be used as appropriate. It is also possible to use two or more of these super absorbent polymer materials in combination.

The amount of superabsorbent polymer material used is 0.00% per sheet.
The weight range is preferably from 1 to 200 g, particularly preferably from 1 to 50 g.

In order to sandwich and integrate the super absorbent material and the specific functional material between the packaging materials, thermoplastic resins such as polyolefin, polyamide, polyester, and other appropriate binders can be used.

In order to manufacture the water absorbent sheet having the functionality of the present invention using the above-mentioned materials, the following method can be used, for example.

That is, a mixture (22) containing a specific functional material and a binder is placed on the packaging material (2) in FIG.
) is evenly dispersed, and then covered with a water-impermeable packaging material (3) and passed through a heated embossing roll to be sandwiched and integrated.

A mixture (21) containing a super absorbent material and a binder is uniformly spread on the sandwiched body, and a packaging material (
1) and pass through a heated embossing roll to integrate.

If the packaging materials (1) and (2) are laminates, cut the sandwiched body, place it on another base material, fold the lower base material into the side part of the base paper, and then insert the other base material from the top. A water-absorbing sheet having the functionality of the present invention can be manufactured by feeding the material, heat-sealing the side portions and end portions, and sandwiching and integrating the entire sheet. (Fig. 2) As a method of sandwiching and integrating the above-mentioned heated embossing rolls, (1) between the heated embossing rolls (2)
) Between a heating embossing roll and a heating roll (3) Between a heating embossing roll and a roll (4) Between a heating roll and a heating roll (5) Between a heating roll and a roll.

The functional water-absorbing sheet of the present invention can be used, for example, as a freshness-preserving material for fresh foods, such as in boxing, bagging, and packaging of fresh foods.
Generally, it is used by inserting it between fresh foods when wrapping trays, etc., but for foods that dry easily, the freshness-preserving material is soaked with water in advance and used in a moist state. It is also possible to do so.

In addition, it can also be processed into an appropriate form and used as a material for sanitary products, diapers, disposable rags, vapor towels, and the like.

〔Effect of the invention〕

As explained above, the use of the water-absorbing sheet having the functionality of the present invention has the advantage that the freshness of fresh foods can be maintained easily and at low cost without requiring much effort.

In addition, because specific functional materials and superabsorbent polymer materials are integrated with the binder, there is a risk that the ethylene gas adsorption side, antibacterial agents, and other functional materials may contaminate fresh foods if the bag is damaged. It has unique effects such as no

Further, there is an advantage that a water absorbent sheet having any function depending on the purpose of use can be created by simply selecting a specific functional material and forming a mixture layer together with a super absorbent material.

Furthermore, the water-absorbing sheet of the present invention is constructed by integrally sandwiching a super-absorbent material and a specific functional material between a water-permeable packaging material and a non-water-permeable, ie waterproof, packaging material. Therefore, it is possible to completely prevent the absorbed moisture from permeating to the back side of the water-absorbing sheet during actual use.The problem of conventional water-absorbing sheets can be solved by a simple means, and the addition of a water-absorbing sheet Since its value can be increased to the general public, its industrial use value is extremely high.

Furthermore, by sandwiching a water-impermeable base material between two types of mixed powder layers, the present invention can, for example, add a water-resistant functional component to one layer and a water-resistant functional component to the other layer through the water-impermeable base material. There is an advantage that even after one component absorbs water, the functionality of the other water-sensitive functional component will not be deteriorated or inactivated by the absorbed water.

Examples and comparative examples of the present invention are described below.

Example 1 Paper with a basis weight of 25 g/rrr (MSP25 manufactured by Maetel)
On top of this, 10g/rd of crushed ethylene gas adsorption/removal agent (Molcibon NGP6/8, manufactured by Takeda Industries) and 0.5g/rd of binder (Chemit R272S, manufactured by Toshisha Co., Ltd.) were added.
Spread it evenly in an amount of rrr, and then cover the paper with polyethylene coated (Maetel MSP25 extrusion coated with M-16P manufactured by Mitsui Nisseki Polymer Co., Ltd. to a thickness of 30μ) with the polyethylene coated side inside. It was passed through a heated embossing roll to be integrated by sandwiching it (heated embossing roll temperature: 160°C).

20g/rd of super absorbent polymer material (Aqua Keep 103HP manufactured by Tetsuo Kagaku Co., Ltd.) is placed on top of the above sandwiched and integrated material.
, binder (Kemi R272S manufactured by Toshisha Co., Ltd.) in 1.
The mixture was uniformly dispersed in an amount of 0 g/rd, covered with paper, and passed through a heated embossing roll to be integrated (heated embossing roll temperature: 160°C).

This was cut to 320 x 210 m, placed on a non-woven fabric (N^240JP2096 manufactured by Kuraray Co., Ltd.), the lower non-woven fabric was folded into the side part of the base paper, the non-woven fabric was fed from the upper part, and the side part was heat-sealed using a gear roll. Then, the end portions were heat-sealed with a seal bar, the whole was sandwiched and integrated, and the end portions were cut to produce a water-absorbing sheet.

Comparative Example 1 Paper with a basis weight of 25 g/rd (MSP25 manufactured by Maetel)
20g/po of super absorbent polymer material (Aqua Keep 103HP manufactured by Tetsuto Kagaku Co., Ltd.) and binder (manufactured by Toshisha Co., Ltd.) on top of the
Chemit R272S) was uniformly dispersed in an amount of Iglof, and then polyethylene-coated paper was further covered and passed through a heated embossing roll to sandwich and integrate (heated embossing roll temperature: 160°C).

Cut the above base paper to 320 x 210 mm,
Placed on non-woven fabric (NA240JP2096 manufactured by Kuraray Co., Ltd.),
The lower nonwoven fabric was folded into the side part of the base paper. Further, a nonwoven fabric was fed from the upper part, the side parts were heat-sealed with a gear roll, the end parts were heat-sealed with a seal bar, the whole was sandwiched and integrated, and the end parts were cut to produce a water-absorbing sheet.

Comparative Example 2 A pulverized product of 10 g/nf of an ethylene gas adsorption remover (Morsibon NGP6/8, manufactured by Takeda Industries, Ltd.) was placed on paper (MSP25 manufactured by Maetel Co., Ltd.) with a basis weight of 25 g/rd, and a super absorbent polymer material (Steel Chemical Co., Ltd.) Aqua Keep l05IP
) to 20 g/n (, binder (manufactured by Toshisha Chemit I)
? 272S) was uniformly sprinkled in an amount of 1.5 g/rrf,
It was covered with polyethylene-coated paper and sandwiched together (heated embossing roll temperature: 160°C).

This was cut to 320 x 210 m, placed on a non-woven fabric (NA240JP2096 manufactured by Kuraray Co., Ltd.), the lower non-woven fabric was folded into the side part of the base paper, the non-woven fabric was fed from the upper part, the side part was heat-sealed with a gear roll, and the end was sealed. The part is heat sealed with a seal bar,
Furthermore, the whole was sandwiched and integrated, and the end portions were cut to produce a water-absorbing sheet.

Experimental Example 1 50 samples of Example 1, Comparative Example 1 and Comparative Example 2 were
Cut to x 50mm and use a vial (125d
ethylene gas is sealed in the bottle so that the ethylene gas concentration is 300 ppm. Ethylene gas concentration was measured by gas chromatography.

Experimental Example 2 50 samples of Example 1, Comparative Example 1 and Comparative Example 2 were
Cut into x 50m+, vial bottle (125d
bottle) to absorb water, and the concentration of ethylene gas in the bottle is 3.
Ethylene gas is sealed to a concentration of 0.00 ppm.

Ethylene gas concentration was measured by gas chromatography in the same manner as in Experimental Example 1.

The results of Experimental Example 1.2 are shown in Table 1.

As is clear from the results in Table 1, the water absorbent sheet of the present invention was found to be excellent.

(Margins below this page) Table 1

[Brief explanation of drawings]

FIG. 1 is a sectional view of a functional water-absorbing sheet showing one embodiment of the present invention. FIG. 2 is a sectional view of a functional water-absorbing sheet showing another embodiment of the present invention. (1), (2), (3)...Packaging material, (21)...
-Mixture, (22)...other mixture.

Claims (4)

[Claims] (1) A mixture (21) containing a highly water-absorbent material and/or a specific functional material is sandwiched and integrated between a packaging material (1) and a non-water permeable packaging material (3), and the sandwiched body A mixture (22) containing a highly absorbent material and/or a specific functional material is sandwiched and integrated between the packaging material (2) and the layer of the highly absorbent material and the layer of the specific functional material. A functional water-absorbing sheet characterized by having a multilayer structure including: (2) The functional water-absorbing sheet according to claim 1, wherein the specific functional material is a material having one or more specific functions such as antibacterial properties, deodorizing properties, or ethylene gas adsorption properties. (3) The functional water-absorbing sheet according to claim 1, wherein the mixture contains a binder made of a thermoplastic resin. (4) The functional water-absorbing sheet according to claim 1, characterized in that the entire structure is integrally sandwiched by heated embossing rolls.