JPS63139556A - Water absorbable sheet or film having antibacterial property - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a water absorbent sheet and film having antibacterial properties.

[Prior Art] As a method of imparting antibacterial properties to organic polymers, a method is known in which zeolite particles holding metals with antibacterial effects are kneaded into organic polymers and molded (Japanese Patent Laid-Open No. 5
8-7361).

[Problems to be Solved by the Invention] The present invention provides an article that further enhances the antibacterial properties of such an organic polymer having antibacterial properties and suitably utilizes its properties, that is, a water-absorbing sheet having antibacterial properties. and film.

[Means for Solving the Problems] The present inventor has added a highly water-absorbent organic polymer containing dispersed zeolite solid particles holding antibacterial metals through ion exchange as described above. The present invention has surprisingly found that antibacterial properties can be significantly improved by adding a polyester resin, and provides a water-absorbent sheet or film that can best utilize the properties of such an organic polymer.

That is, the present invention provides zeolite-based solid particles and super absorbent resins having a specific surface area of 1507 rt/g or more and a Si 02 / All 203 molar ratio of 14 or less, which retain metal ions having an antibacterial effect by ion exchange. It is a water-absorbing sheet or film having antibacterial properties, which is made of a film-forming resin and a film-forming resin.

BACKGROUND ART Conventionally, sheets and films using superabsorbent resins are known as water-absorbing sheets and films.

Ceiling materials, wall materials, fittings, equipment packaging materials to prevent condensation, water supply panels to provide water expansion properties, backings, gaskets,
It is used as a water retaining material for agricultural and gardening materials, and as a water cushioning material for beds and furniture underbats.

However, mold and bacteria tend to grow on and around the surfaces of sheets and films. Therefore, if this is used as a water retaining material, mold may grow on the surface of the seedbed.
Or when used as a dew prevention material, ceiling panels, wallpaper,
There is a problem with mold growing on the fittings. Furthermore, when used as a water cushioning material, the water rots due to the growth of mold and bacteria, resulting in unsanitary conditions. Therefore, it is possible to use a disinfectant. Environmental disinfectants include halogen disinfectants, oxygen disinfectants, surfactants, aldehyde disinfectants, alcohol/phenol disinfectants, eboxide and biguanide disinfectants, but all of these are harmful to the human body. It is. Since it is an organic compound, it has poor heat resistance and will decompose or volatilize when heated or processed.
It was impossible to incorporate it into water-absorbing sheets and films.

The present invention takes advantage of the fact that the antibacterial performance of an organic polymer containing dispersed zeolite particles holding antibacterial metals can be greatly enhanced by adding a superabsorbent resin to it, and This solution solves the drawbacks of water-absorbent sheets and films.

In the present invention, zeolites 1~ (hereinafter sometimes simply referred to as zeolites having antibacterial effects) which retain metal ions having antibacterial effects through ion exchange are used in Japanese Patent Application Laid-open No. 5
8-7361.

In other words, zeolite solid particles that have antibacterial effects are:
One or more metal ions having an antibacterial effect are retained in the ion-exchangeable portion of natural or synthetic zeolite made of aluminosilicate. Preferred examples of metal ions having antibacterial effects include silver, copper, zinc, tin, lead, bismuth, cadmium, chromium, and mercury, with silver, copper, and zinc being preferred. The above-mentioned antibacterial metals can be used alone or in combination.

Zeolites are generally aluminosilicates with a three-dimensionally developed skeletal structure, and are generally AJ2203
Based on XM2/, 0・AfJ 203” ys
! 02 ・Z Represented by H20.

M represents an ion-exchangeable metal ion, usually a monovalent to divalent metal, and n corresponds to this valence. On the other hand, X and y represent coefficients of total oxide and silica, respectively, and Z represents the number of crystallized water.

Many types of zeolites are known, differing in their composition ratio, pore diameter, specific surface area, etc.

However, the specific surface area of the zeolite solid particles used in the present invention must be 150 m/9 or more (based on no zeolite), and the 5i02/AfJ2 o3 molar ratio of the zeolite constituents must be 14 or less, preferably 11 or less.

The solution of water-soluble salts of metals with antibacterial activity, such as silver, copper, and zinc, used in the present invention easily undergoes ion exchange with the zeolite defined in the present invention, so this phenomenon can be utilized to obtain the necessary solutions. It is possible to hold the above metal ions alone or in combination in a zeolite stationary phase, but olide particles that hold metal ions are
The specific surface area is 150Trt/g or more, and S! 02/
Two conditions must be met: the AN203 molar ratio is 14 or less. If this is not the case, the object of achieving effective antibacterial action will not be obtained. This is thought to be due to the fact that the absolute amount of metal ions fixed on the zeolite is insufficient in a state where the effect can be exerted. In other words,
This is thought to be due to the physicochemical properties of the zeolite's exchange groups, such as its poor performance, exchange rate, and accessibility.

Therefore, SiO, known as molecular sieve
Zeolites with a large 3/Aρ203 molar ratio are completely unsuitable for the present invention.

In addition, zeolites with a S l 02 / Aft 203 molar ratio of 14 or less can uniformly retain metal ions that have antibacterial effects, and for this reason, it is only by using such zeolites that a sufficient antibacterial effect can be obtained. It turned out that it was possible. In addition, zeolite S
i 02 / Aft 203 The acid resistance and alkali resistance of zeolite with a high silica ratio exceeding 14 is 5i.
The silica content increases as n2 increases, but its synthesis also takes a long time, and from an economic standpoint, it is not a good idea to use zeolites with such high silica ratios. The aforementioned S! 02 /
AI! Natural or synthetic zeolites of 203≦14 can be used satisfactorily from the viewpoint of acid resistance and alkali resistance in the fields of application normally considered for the present invention, and are economically advantageous as they are inexpensive. In this sense, S
i 02 / AJJ 203 Mo11. i ratio c14
The following text does not apply.

As the zeolite material having a Si02/Al1203 molar ratio of 14 or less used in the present invention, any natural or synthetic zeolite can be used.

For example, natural zeolite is analcin (Anal
cime: Si 02 /A, ff 203 = 3
．． 6-5.6), Chabazite
:S! 02/A, 11203=3.2~6.0
and 6.4-7.6>, clinoptilolite (C1
inoptilolite: Si 02 /A,Q
2 o3 = 8.5~10.5>, erionite (E
rionite: Si 02 /Al! 203=
5.8-7.4), Faujasi
te: Si02/to ρ203=4.2~4.
8>, mordenite (Si
O/11203 = 8.34~io, o), Phillipsite:S!02
/AN 203 = 2.6 to 4.4). These typical natural zeolites are suitable for the present invention. On the other hand, typical synthetic zeolites include 8-
type zeolite (S102/Aft 203= 1.4~
2.4) , X-type zeolide (3iQ/Aρ203=
2-3), Y-type zeolite (S!02/A
, G203 = 3-6), mordenite (SiO2
/Ag2o3=9-10), and these synthetic zeolites are suitable as the seolide material of the present invention. Particularly preferred are synthetic 8-type zeolites,
X-type zeolites, Y-type zeolites and synthetic or natural mordenites.

The shape of the zeolite is preferably in the form of powder particles, and the particle size may be appropriately selected depending on the application. For example, several microns - several 1
0 micron, several hundred microns or more, or 5
It can be less than a micron, especially less than 2 microns.

Metal ions must be retained in the zeolite solid particles through an ion exchange reaction. If it is simply adsorbed or attached without ion exchange, the antibacterial effect and its durability will be insufficient. As a method for retaining metal ions, various zeolites defined in the present invention can be used in A of the present invention.
For example, when converting to g-zeolite, normally Ag
- A solution of a water-soluble silver salt such as silver nitrate is used during zeolite conversion, but care must be taken not to increase its concentration too much. For example, when converting A-type or As a result of the exchange, i ions are replaced with sodium ions in the same phase, and at the same time, silver oxides and the like are precipitated in the zeolite solid phase.

This has the disadvantage that the porosity of the zeolite is reduced and the specific surface area is significantly reduced. Furthermore, even if the specific surface area does not decrease significantly, the bactericidal activity decreases due to the presence of silver oxide itself. In order to prevent the precipitation of excess silver into the zeolite phase, the concentration of the silver solution should be diluted, for example 0.3M.
It is necessary to keep the AON below 03. The safest concentration of A(]NO3 is 0.1M or less. When using an AgNO3 solution with such a concentration, the Ag-
The specific surface area of zeolite is almost the same as that of zeolite, the converted material, and it was found that the antibacterial effect can be exerted under optimal conditions.

Next, when the zeolites defined in the present invention are converted to Cu-zeolite, the same phenomenon as in the case of Ag-zeolite described above occurs depending on the concentration of the copper salt used for ion exchange. For example, when converting 8-type or Due to the precipitation of basic precipitates such as Cu 3 (SO 4 ) (OH) 4 , the porosity of the zeolite decreases 1 and the specific surface area decreases significantly. In order to prevent such excessive copper precipitation into the zeolite phase, it is preferable to maintain the concentration of the aqueous preparation used in a more dilute state, for example, 0.05M or less.

When using a CuSO4 solution with such a concentration, the Cu obtained
-The specific surface area of zeolite is almost the same as that of zeolide, which is a conversion material, and it has been found that it has the advantage of being able to exhibit its antibacterial effect in an optimal state.

A (Although it was mentioned that during conversion to 1-zeolite and Cl-zeolite, solids may be precipitated in the same phase of zeolite depending on the concentration of salts used for ion exchange.
When converting to Zn-zeolite, such a phenomenon is not observed when the salt content used is around 2 to 3M. Generally, the Zn-zeolite used in the present invention can be easily obtained by using salts having concentrations around the above range.

A (J-zeolite, Cu-zeolite and Z
When carrying out the ion exchange reaction in a batch process for conversion to n-zeolite, the zeolite material may be immersed in a salt solution having the above-mentioned concentration. In order to increase the metal content in the zeolite material, the number of batch treatments may be increased. On the other hand, when treating a zeolite material by a column method using a salt solution having the above concentration, the desired metal-zeolite can be easily obtained by filling an adsorption tower with the zeolite material and passing the salt solution through it. can get.

The metal matrix in the above metal-zeolite (based on anhydrous zeolite) is 30% by weight or less of silver,
The preferred range is between o, ooi and 5% by weight. -6 Regarding the copper and zinc used in the present invention, the amount of copper or zinc in the metal zeolite (based on anhydrous zeolite) is 35% by weight or less, and the preferable range is 0.01 to 15% by weight.
It is in weight%. It is also possible to use silver, copper and zinc ions in combination, in which case the total amount of metal ions is 35% of the metal-zeolite (based on anhydrous zeolite).
The amount may be less than 1% by weight, and the preferable range depends on the composition ratio of metal ions, but is approximately 0.001 to 15% by weight.

Furthermore, even if metal ions other than silver, copper, and zinc, such as sodium, potassium, calcium, or other metal ions, coexist, the antibacterial effect will not be hindered, so the residual or coexistence of these ions is not a problem. do not have.

The proportion of the metal having an antibacterial effect relative to the total amount of zeolite (based on anhydrous zeolite) may be 30% by weight or less for silver, and the preferred range is from o,ooi to 5% by weight. On the other hand, in the case of copper or zinc, the content is 35% or less, and the preferred range is 0.01 to 15% by weight. When silver, copper and zinc ions are used in combination, the total amount of metal ions is preferably in the range of 0.001 to 15% by weight.

Further, there is no problem with the remaining or coexistence of other mirror ions.

The content of antibacterial zeolite solid particles holding antibacterial metal ions (based on anhydrous zeolite) is 0.01 to 0.01 of the total weight of the sheet or film that has not absorbed water.
It is preferably 50% by weight, particularly 0.1 to 10% by weight.

The super absorbent resins used in the present invention include starch/acrylate graft polymers, carboxymethylcellulose crosslinked products, vinyl alcohol/acrylate copolymers, polyacrylonitrile hydrolysates, crosslinked polyacrylates, modified Examples include resins having high water absorption properties such as polyvinyl alcohol, acrylate polymers, acrylate/acrylamide copolymers, and isobutylene/maleic anhydride copolymers. It is also possible to use two or more of the above superabsorbent resins. The content of superabsorbent resin is 1 to 100% of the weight of the sheet or film (dry basis).
Preferably within the range of 80% by weight, particularly 10 to 60% by weight
It is desirable to be within the range of .

As the film-forming resin used in the present invention, any resin commonly used for making sheets or films can be used.

In particular, vinyl chloride resin, ethylene-vinyl acetate copolymer resin, urethane resin, acrylic resin, silicone resin, natural rubber, ethylene-propylene rubber, chlorobrene, butyl rubber, styrene-butadiene rubber, etc., or a mixture of two or more of these are desirable. .

In the present invention, the term "sheets" and "films" refers to sheets and films themselves, laminates thereof, or laminates made of these and paper, nonwoven fabric, aluminum foil, etc. The sheets and films of the present invention can be made by appropriately mixing an antibacterial zeolite, a superabsorbent resin, and a film-forming resin, and molding the mixture by a conventional method.

[Effects of the Invention] According to the present invention, the antibacterial action of a resin article containing zeolite retaining antibacterial metals was significantly enhanced by the addition of a superabsorbent resin. A sheet or film made from a resin composition containing such an antibacterial zeolite and a superabsorbent resin has excellent performance as a water absorbent sheet or film having antibacterial properties.

[Example] In the following, the invention will be explained in more detail by means of examples.

The antibacterial zeolite used in the present invention is Bactekiller A
350 BN (trademark, manufactured by Sinanen New Ceramics). This is made by adding 3% by weight of silver and 5% by weight of copper to A-type zeolite by ion exchange, and has an average particle size of 5 to 6 μm. Specific surface area is 500-600 TIt/g, Si 02
/l! The 203 molar ratio is approximately 2.

Example 1 5% by weight of antibacterial zeolite solid particles were added to a resin composition consisting of an acrylic acid/vinyl alcohol copolymer and an equal amount of ethylene vinyl acetate copolymer (EVA), and the mixture was mixed in a mixer at a processing temperature of 120'C. The mixture was kneaded and made into a sheet using a heat press machine. The thickness of the sheet was 1Mll1.

Example 2 30% by weight of acrylic acid/vinyl alcohol copolymer and 5% by weight of antibacterial zeolite solid particles were kneaded into 65% by weight of EVA resin to form a sheet in the same manner as above.

Comparative Example 1 Pellets consisting of 50% by weight of acrylic acid/vinyl alcohol copolymer and 50% by weight of EVA resin were formed into a sheet using a hot press machine.

Comparative Example 2 Acrylic acid/vinyl alcohol copolymer 30@i% and E
70% by weight of VA resin was kneaded into a sheet in the same manner as in Example 1.

Comparative Example 3 Antibacterial zeolite 5% by weight was kneaded into an ethylene vinyl acetate copolymer resin in the same manner as in Example 1, and a sheet was formed.

Antibacterial Evaluation Experiment The above five types of sheets were cut into 5 x 5 pieces, and after absorbing water, the antibacterial effect was examined. In the experiment, spores of Bacillus subtilis and Aspergillus niger 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, 100m1 of Tween
Bacteria on the surface of each sheet was washed off in sterilized water containing 800.1%, and the number of viable bacteria in this sterilized water was measured using an ordinary agar medium (manufactured by Eiken Chemical Co., Ltd.) for Bacillus subtilis, and for black mold. Using a potato dextrose agar medium (manufactured by Eiken Chemical Co., Ltd.), measurement was performed by a conventional pour plate culture method, and the number of viable bacteria adhering to each sheet was calculated. The results are shown in the table.

From the above table, it can be seen that the water absorbent sheet of the present invention has a more pronounced antibacterial effect than the conventional water absorbent sheets (Comparative Examples 1 and 2). Furthermore, the water absorbent sheet of the present invention containing a super absorbent resin has a clearly improved antibacterial effect compared to a sheet that does not contain the super absorbent resin (Comparative Example 3).

Kanebo Co., Ltd. Applicant Dai Nippon Printing Co., Ltd. Hagiwara Giken Co., Ltd.

Claims (6)

[Claims] (1) Zeolite solid particles, superabsorbent resin, and film that retain metal ions with antibacterial effects through ion exchange and have a specific surface area of 150 m^2/g or more and a SiO_2/Al_2O_3 molar ratio of 14 or less. A water-absorbing sheet or film made of moldable resin and having antibacterial properties. (2) The zeolite solid particles are A-type zeolite, X-type zeolite
A sheet or film according to claim 1, which is composed of type zeolite, Y-type zeolite or mordenite. (3) The sheet or film according to claim 1 or 2, wherein the metal ion having an antibacterial effect is one or more metal ions selected from the group consisting of silver, copper, and zinc. (4) The content of zeolite solid particles (based on anhydrous zeolite) is 0 of the total weight of the sheet or film (dry basis)
．． Claims 1 to 3 which are 01 to 50% by weight
A sheet or film as described in any one of paragraphs. (5) The super absorbent resin is a graft polymer of starch/acrylate, crosslinked carboxymethyl cellulose, vinyl alcohol, acrylate copolymer, polyacrylonitrile hydrolyzate, crosslinked acrylate/acrylamide copolymer, acrylic The sheet or film according to any one of claims 1 to 4, which is an acid salt polymer, a polyacrylate, a modified polyvinyl alcohol, or an isobutylene/maleic anhydride copolymer. (6) The sheet or film according to any one of claims 1 to 5, wherein the content of the superabsorbent resin is 1 to 80% by weight of the total weight of the sheet or film (dry basis). .