JPH02307528A - Composition for water absorbing sheet - Google Patents

Abstract

PURPOSE:To obtain a water absorbing sheet equipped with high water absorbability and specific function by holding a highly water-absorbable polymer material and a specific functional material between specific packing materials to form the whole into a sheet-like shape. CONSTITUTION:A highly water-absorbable material, a material 3 having specific function such as a substance carrying a deodorant and an antibacterial substance and, if necessary, a binder are sandwiched between inner layers 2, 4 composed of paper. Thereafter, this sandwiched body is packed in a packing back prepared from outer layers 1, 5 composed of a nonwoven fabric to form a water absorbing sheet. As mentioned above, since the highly water-absorbable material and the specific functional material are contained, the water absorbing sheet equipped with arbitrary function corresponding to a use purpose is obtained. Therefore, this sheet can be simply used in a low cost without taking labor and has wide use as a diaper, a paper towel or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a composition for functional water-absorbing sheets, and more specifically to freshness-keeping materials for fresh foods, sanitary products, diapers, disposable rags, The present invention relates to a composition for a water-absorbing sheet that has specific functions useful as a material for products such as paper towels that require high water-absorbing properties.

[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, conventional methods of transporting fruits and vegetables have included two types of freshness-preserving materials, for example, a water-absorbing sheet made of super absorbent resin and an ethylene gas adsorbent, packed in boxes or bags. There are known ways to store them.

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 those with super-absorbent resin powder 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 a resin, and an adhesive layer is formed on the non-patterned part and other sheet base materials are laminated. There is.

[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. In the case of packaging, there are various problems such as extra effort, a decrease in overall work efficiency, and an increase in 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 they are susceptible to contamination by food spoiling bacteria. It is impossible to reliably prevent the deterioration of freshness of fresh foods caused by water-absorbing sheets 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, once frozen 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.

Furthermore, 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.

Under these circumstances, the inventors of the present invention have conducted intensive research to solve the problems of the above-mentioned conventional technology, and as a result, have developed a specific composition containing a super absorbent material and a specific functional material. The present invention has been completed by discovering that the above-mentioned problems can be solved by combining a specific packaging material to form a water-absorbing sheet that has both water-absorbing properties and specific functions.

That is, an object of the present invention is to provide a novel water-absorbing sheet composition that has high water absorbency and specific functions, 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 relates to a composition containing a superabsorbent polymer material and a specific functional material, which is placed between a specific packaging material. These are sandwiched and integrated to form a sheet-like product.
Specifically, they are as follows.

(1) A composition for a functional water-absorbing sheet, which contains at least a super-absorbent material, a specific functional substance, and, if necessary, a binder.

(2) The composition according to (1) above, wherein the functional substance is a carrier supporting an antibacterial substance having antibacterial properties.

(3) The composition according to (1) above, wherein the functional substance is a powder having deodorizing properties.

(4) The above (4) characterized in that the functional substance is a carbon molecular sieve having 4 to 6 micropores adsorbed with bromine.
1) The composition described.

(5) The composition according to (1) above, wherein the functional substance is obtained by dissolving sodium bromate or potassium bromate, adding acidic water to activated carbon, reacting it, and then drying it.

(6) The composition according to (1) above, wherein the binder is a thermoplastic resin.

(7) The composition as described in (1) above, which comprises a paint or printing ink containing a water-absorbing resin and a functional powder.

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

FIG. 1 shows an example of the use of the composition of the present invention,
After a composition 3 containing a super absorbent material and a deodorizing agent as a specific functional material is sandwiched and integrated between inner layers 2 and 4 made of paper, the sandwiched body is transferred to an outer layer 1 made of nonwoven fabric. FIG. 2 is a sectional view of a functional water-absorbing sheet product packaged with a packaging bag made of outer layer 5.

Examples of packaging materials constituting the inner layer and outer layer include:
Sizeless paper, non-woven fabric, water-permeable porous sheets such as hydrophilic polyethylene and polypropylene, cellophane, vinylon film, thermoplastic film that has been foamed to have fine continuous pores during film production, inorganic or high melting point Papers with microscopic pores formed by adding a nucleating agent and stretching, other mixed papers of polyethylene or polypropylene and pulp, laminates of paper and nonwoven fabrics, cellulose membranes formed with viscose on sized paper and nonwoven fabrics. Appropriate types of water-permeable materials are used, such as cellulose membranes with microscopic pores formed therein, as well as appropriate types of non-water-permeable materials such as plastic films made of thermoplastic resin, PE paper, and metal foils. It is also possible to use flexible materials.

In particular, nonwoven fabrics include nonwoven fabrics that are partially or entirely made of thermoplastic resin, such as fibers such as rayon and pulp.
It is preferable to use a nonwoven fabric impregnated with or mixed with a resin such as polyolefin, polyester, or polyamide, or a nonwoven fabric made of fibers such as polyolefin, polyester, or polyamide, and has a basis weight of 15 to 100 g/
m” is preferred.

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

Among the materials such as the super absorbent material and the specific functional material constituting the composition 3 of the present invention, the functional material may have an appropriate function such as an antibacterial agent, a deodorizing agent, an ethylene gas absorbent, or a combination thereof. Substances or compositions with appropriate multiple functions are used.

Antibacterial agents include antibacterial metal materials such as silver, copper, zinc, tin, lead, bismuth, cadmium, chromium, and mercury, as well as zeolite, activated carbon, silica, activated clay, acid clay, alumina, activated bauxite, and bone charcoal. , molecular sieves, or other carriers are preferable, but these antibacterial materials, types of carriers, and amounts used are not particularly limited.

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 (■) compounds, L-ascorbic acid and alum, 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. These deodorizers are sheet ll
It is preferable to mix it with a super absorbent material and fix it between packaging materials so that it is sandwiched in a range of 0.1 to 150 g per 1z.

As the ethylene gas adsorbent, a carbonaceous molecular sieve adsorbed with bromine, preferably one having 4 to 6 micropores,
Alternatively, examples include particles having a particle size of 5 to 500 μm, which are obtained by adding acidic water in which sodium bromate or potassium bromate is dissolved to activated carbon and reacting the mixture, followed by drying and pulverization.

This kind of ethylene gas adsorbent is not affected by moisture,
That is, it is desirable because the adsorbed ethylene gas is not released 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, examples of highly water-absorbent materials include glucose, fructose, and Sea II! , maltose, lactose, sorbitol, maltitol, reducing starch hydrolyzate, locust bean gum, tamarind seed gum, carrageenan, silica gel, zeolite, sodium chloride, calcium chloride, starch/acrylate graft polymer, carboxymethylcellulose cross-linking vinyl alcohol/acrylate copolymer, polyacrylonitrile hydrolyzate, crosslinked polyacrylate, modified polyvinyl alcohol, acrylic acid polymer, acrylate/acrylamide copolymer, isobutylene/maleic anhydride copolymer For example, other materials having high water absorbency 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 to be used is preferably in the range of 0.1 to 200 g, particularly preferably in the range of 1 to 50 g per m2 of sheet.

In order to bind and integrate the super absorbent material and the specific functional material between the packaging materials, thermoplastic resins such as polyolefins, polyamides, polyesters, and other suitable binders can be used.

The functional water-absorbing sheet composition of the present invention can be used in the form of a coating agent (ink or paint) dispersed in a paint vehicle or a printing ink vehicle. Solvents for coating agents include aliphatic hydrocarbons, aromatic hydrocarbons, alcohols, ketones, esters, chlorine-containing hydrocarbons, nitrogen-containing hydrocarbons, or mixtures thereof, which are used in ordinary paints and printing inks. Use organic solvents such as those listed.

Binders in the vehicle include, for example, linseed oil,
Natural or synthetic drying oils such as linseed oil, soybean oil, dehydrated castor oil, styrenated oil, vinyltoluenated oil, maleic oil, natural resins such as rosin, copal, dammar, shellac, hardened rosin, rosin esters, etc. Processed resin, polyvinyl acetate resin, polyvinyl alcohol,
Polyvinyl butyral, polystyrene resin, acrylic resin, phenolic resin, looseness resin, unsaturated polyester resin, alkyd resin, polyamide resin, epoxy resin, polyurethane resin, aminoplast resin, petroleum-based resin Synthetic resins such as resins, fiber derivatives such as nitrocellulose, methyl-, ethyl-, carboxymethyl- or acetylbutyryl-cellulose, chlorinated rubber,
Any binder conventionally used in paints or printing inks can be used, such as rubber derivatives such as cyclized rubber, or one or a mixture of two or more of glue, casein, dextrin, and the like.

The amount of superabsorbent polymeric material in the coating agent is generally in the range of 5 to 70%. If the amount is less than this range, the water absorption capacity will be insufficient, while if it exceeds the above range, the adhesion of the water absorbing layer will be insufficient, which is not preferable.

The amount of binder may be 5 to 50% (same as in conventional paints and printing inks).

The coating agent used in the present invention has a specific functional substance as an essential component, but it also contains various known additives for paints and printing inks, such as plasticizers, stabilizers, waxes,
Grease, desiccant, auxiliary desiccant, dispersant, thickener, filler, ultraviolet absorber, etc. can all be used as necessary.

In order to produce a functional water-absorbing sheet using the composition of the present invention, the following method can be used, for example.

That is, a composition 3 containing a super absorbent material, a specific functional material, and a binder is uniformly spread on the inner layer material 4 in FIG. After being sandwiched and integrated, the integrated base paper is cut to a certain size, which is then manually stuffed into the outer layer materials 1 and 5 consisting of a three-sided seal pouch, sealed, and then the whole is passed through a heated embossing roll and sandwiched. It can be manufactured by integrating the parts. Note that the inner layer and outer layer materials are not limited to a single layer, and any appropriate laminate composed of multiple layers can be used.

As a method of sandwiching and integrating the above-mentioned heating embossing rolls, (1) between the heating 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 produced using the composition of the present invention can be used as a freshness-preserving material for fresh foods, for example, when the fresh foods are packed in boxes, bags, trays, etc. Generally, the freshness-preserving material is used by inserting it into a container, but for foods that dry easily, it is also possible to use the freshness-preserving material in a moist state by absorbing water in advance.

In addition, it can be processed into an appropriate form and used as a material for sanitary products, diapers, disposable miscellaneous goods, paper towels, etc.

〔Effect of the invention〕

As explained above, the use of the functional water-absorbing sheet composition of the present invention has the advantage that the freshness of perishable foods can be maintained easily and at low cost without requiring much time and effort. In addition, because specific functional materials can be integrated with superabsorbent polymer materials, there is no risk of functional materials such as ethylene gas adsorbents and antibacterial agents contaminating fresh foods due to bag breakage, etc. You can expect unique effects such as:

Further, there is an advantage that a water-absorbing sheet composition having any function depending on the purpose of use can be created by simply selecting and mixing a specific functional material together with a highly water-absorbent material.

Furthermore, in a water absorbent sheet using the composition of the present invention,
If a highly water-absorbent material is sandwiched between a water-permeable packaging material and a water-impermeable (waterproof) packaging material, the water absorbed during actual use will flow to the back side of the water-absorbing sheet. It is possible to completely prevent permeation, solve the problems of conventional water-absorbing sheets with simple means, and further increase the added value of water-absorbing sheets, so its industrial value is extremely high. It is.

Examples of the present invention are described below.

[Example] Example 1 Activated carbon (Shirasagi A, manufactured by Souen Yakuhin Kogyo Co., Ltd.) was applied as a deodorizer on paper (MSP25, manufactured by Maetel Co., Ltd.) with a basis weight of 25 g/a''.
), a mixture of organic acid and zinc oxide (manufactured by Dainichiseika Kagyo Co., Ltd.)
Guimshu 1300) respectively log/112, super absorbent polymer material (manufactured by Steel Chemical Co., Ltd. Aqua Keep 1OSIP)
) and 10 g/m'' of binder (Flowback manufactured by Steel Chemical Co., Ltd.) (f! Integrated. (heat roll temperature 14
0°C, embossing pressure 5kg/-”) The above base paper was
Cut to x 200+nm, basis weight 25g/mg
Non-woven fabric (Mitsui Petrochemical Co., Ltd. Syntex P 105)
) 3-sided sealed pouch (size 330 x 210 +++ m
) and sealed by hand.

Comparative Example 1 A drip sheet similar to Example 1 was manufactured without adding a deodorizing agent.

Experimental Example 1 Thaw frozen horse mackerel, package it according to the method shown in Table 1, and
After storage in a refrigerator at 7°C for days, the generation of drips and odor were compared. The results are shown in Table 1.

From the results shown in Table 1, it can be seen that when the drip sheet of this example is used, neither drip nor odor is generated.

Example 2 A pulverized product of 10 g/m'' of an ethylene gas adsorption remover (Molcibon NGP6/8, manufactured by Shikinichi Yakuhin Kogyo Co., Ltd.) and a highly water-absorbent product were placed on top of the tsuki (MSP25 manufactured by Maetel Co., Ltd.) with a basis weight of 25 g/m''. Molecular material (manufactured by Steel Chemical Co., Ltd. Aqua Keep 10SHP
) 70g/mt, a composition containing 0.5g/mt of binder (Chemit R272S manufactured by Toshisha Co., Ltd.) was evenly dispersed, and the paper was further coated with polyethylene (Maetel MSP25 and L manufactured by Mitsui Nisseki Polymer Co., Ltd.).
16P coated with extrusion resin to a thickness of 30μ) with the polyethylene coated side inside, and passed through a heated embossing roll to sandwich and integrate (heated embossing roll temperature: 160°C).

A super absorbent polymer material (Aqua Keep 103IIP manufactured by Steel Chemical Co., Ltd.) was applied at 20 g/m'' on top of the paper coated with polyethylene, which was integrated with the sandwiched material, and a binder (
Chemit R272S (manufactured by Toshisha Co., Ltd.) is uniformly sprinkled at an amount of 1.0 g/m'', then covered with paper, and passed through a heated embossing roll to sandwich and integrate (heated embossing roll temperature 160
℃).

This is cut into a size of 320:x210vw, placed on a nonwoven fabric (NA240JP2096 manufactured by Kuraray Co., Ltd.), and the lower nonwoven fabric is folded into the side portion of the base paper. Furthermore, the nonwoven fabric is fed from the upper part, and the side part is heat-sealed by a gear roll. The end part is heat sealed with a seal bar,
Furthermore, the whole is unified and cut at the end.

Experimental Example 2 The sample of Example 2 was cut to 50×501111I, placed in a vial (125 d capacity), and ethylene gas was sealed in the vial so that the ethylene gas concentration was 300 ppm+. Ethylene gas concentration was measured by gas chromatography.

Experimental Example 3 The sample from Example 2 was cut into 50 x 5011 (l) pieces, placed in a vial (12!1iIIt volume) to absorb water, and ethylene gas was sealed in the bottle so that the ethylene gas concentration was 300 pp-. do.

Ethylene gas concentration was measured by gas chromatography in the same manner as in Experimental Example 2.

The results of Experimental Example 2.3 are shown in Table 2.

Table 2 (unit: ppm) Example 3 A crushed product (average Particle size 25u
m) A composition containing 20 g/m", a super absorbent polymer material (Aqua Keep IOSIP manufactured by Steel Chemical Co., Ltd.) 70 g10+", and a binder (Flowback manufactured by Steel Chemical Co., Ltd.) (EVA powder) lOg/fi" was uniformly mixed. It is then sandwiched between paper of the same type and passed through heated embossing rolls to integrate it (thermal roll temperature 140°C, embossing pressure 5kg/
cab”).

The above base paper was cut into 320 x 200+ss+, and a three-sided sealed pouch (size 3
30 x 210 am) and seal.

Comparative Example 2 In Example 1, a fruit and vegetable freshness-keeping material without the ethylene gas adsorption/removal agent was produced.

Experimental Example 4 Ten pieces of each Sudachi from Tokushima Prefecture were packaged and bagged according to the method shown in Table 1, and stored at 5°C for 3 months.

The results are shown in Table 3.

(Margin below this page) Table 3 Example 4 Acrylate-based super water absorbent resin (Aqua Keep 10SH
-P (trademark: Steel Chemical Industry ■)), particle size 100 μ, water absorption capacity pure water 500 ad/g, sheep blood 50 d/g), 10 g), 5 g of zeolite solid particles carrying antibacterial metal ions, and ethylene as an adhesive. - A composition containing 5 g of vinyl acetate copolymer was sprayed and heated and pressed using a 100''C heating roll to obtain an antibacterial water-absorbing sheet.

Comparative Example 3 Example 1 was repeated except that the zeolite solid particles carrying antibacterial metals were not used.

Comparative Example 4 Example 1 was repeated except that no superabsorbent resin was used.

Antibacterial Property Evaluation Experiment The above three types of sheets were cut into 5 x 5 C1 pieces, and after absorbing water, the antibacterial effect was examined. In the experiment, spores of Bacillus subtilis and Aspcrgillus nigcr were sprayed onto each sheet, and the number of surviving bacteria was measured immediately after spraying and after storage at 22° C. and 90% relative humidity for 7 days. The measurements were performed using the following procedure. That is, Twe of 100I11
Wash the bacteria on the surface of each sheet in sterilized water containing 0.1% EN80, count the number of viable bacteria in this sterilized water, use an ordinary agar medium (manufactured by Eiken Chemical Co., Ltd.) for Bacillus subtilis, and measure the number of viable bacteria in the sterilized water for black mold. Potato dextrose agar medium (manufactured by Eiken Chemical)
The number of live bacteria adhering to each sheet was calculated by measuring by the usual pour plate culture method. The results are shown in Table 4.

Table 4 From Table 4 above, it can be seen that the antibacterial water-absorbing sheet of the present invention has a remarkable antibacterial effect compared to Comparative Example 1 (no antibacterial zeolite) and Comparative Example 2 (no superabsorbent resin). .

[Brief explanation of drawings]

FIG. 1 shows a cross-sectional view of a freshness-preserving material that is an embodiment of the present invention. 1... Nonwoven fabric (outer layer) 2... [; (inner layer) 3... Composition consisting of a highly absorbent material and a deodorizing agent 4...
Gion (inner layer) 5... Nonwoven fabric (outer N)

Claims (7)

[Claims] 1. 1. A composition for a functional water-absorbing sheet, comprising at least a super-absorbent material, a specific functional substance, and, if necessary, a binder. 2. 2. The composition according to claim 1, wherein the functional substance is a carrier supporting an antibacterial substance having antibacterial properties. 3. 2. The composition according to claim 1, wherein the functional substance is a powder having deodorizing properties. 4. 2. The composition according to claim 1, wherein the functional substance is a carbon molecular sieve having micropores of 4 to 6 Å and adsorbed with bromine. 5. 2. The composition according to claim 1, wherein the functional substance is obtained by dissolving sodium bromate or potassium bromate, adding acidic water to activated carbon, causing the reaction, and then drying. 6. A composition according to claim 1, characterized in that the binder is a thermoplastic resin. 7. 2. The composition according to claim 1, comprising a paint or printing ink containing a water-absorbing resin and a functional powder.