JPS62241932A - Polymer foam having antibacterial and antifungal function and its production - Google Patents

Abstract

PURPOSE:To obtain the titled nontoxic, thermally stable foam which can show both antibacterial and antifungal effects for a prolonged period of time even when used in a small amount, by heat-treating a mixture of a specified activated fine zeolite powder with a polymer and foaming this mixture. CONSTITUTION:A porous natural or synthetic zeolite having an ion exchange capacity >=11meq/g (dry basis) and a large specific surface area is allowed to carry 0.005wt% (dry basis) at least one bactericidal metal selected from among silver, copper, zinc and thin and is activated by heating so as to adjust the water content to 5wt% and the average particle diameter to 15mu or below. In this way, activated fine zeolite powder (B) is obtained. A mixture obtained by mixing a polymer (A) such as PE, PS, PVC, polyurethane resin, nylon or rubber with 0.03% above component B is heat-treated to form a uniform mixture, and this mixture is mechanically foamed by using an inert gas such as CO2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a polymeric foam having antibacterial and antifungal functions and a method for producing the same. More specifically, the present invention relates to a polymeric foam having antibacterial and antifungal functions, characterized in that it contains a zeolite holding a metal having a bactericidal effect, that is, an inorganic antibacterial biolyte.
This is related to six methods of A construction.

[Prior art and its problems] It has been generally believed that polymers (plastics) are highly resistant to microorganisms such as fungi and bacteria, but this is now nothing more than a legend. do not have. To date, many examples of damage caused by microorganisms to various plastics have been reported from various quarters. For this reason, mold-proofing treatment is now included in the specifications for certain plastic applications. Plastics contain plasticizers, stabilizers,
Fillers, antioxidants, ultraviolet absorbers, lubricants, colorants, modifiers, compounding materials, etc. are added. In addition, at the stage of plastic molding, auxiliary agents and additives such as lubricants, antioxidants, spreading agents, and mold release agents are used as necessary. Based on the above, many plastic molded objects, regardless of their shape, are susceptible to attack and deterioration by microorganisms. The present inventor has conducted research on commercially available urethane foam, polyvinyl chloride, polyethylene, and other foams according to
When these mold resistance tests and its antibacterial activity tests were carried out using the method of 21, it was found that all commercially available foams had very little resistance to bacteria and general bacteria. For this reason, we conducted extensive research on antibacterial agents suitable for polymer foams in order to prevent the growth of mold on polymer foams as much as possible and to impart antibacterial activity against common bacteria.

As a result, polymer foams containing inorganic antibacterial zeolite have many characteristics compared to those containing known organic antibacterial agents, and their antifungal properties are also superior to the latter. I discovered that. The polymer foam containing the above-mentioned antibacterial zeolite has greater antibacterial activity against not only fungi (molds) but also general bacteria than commercially available organic antibacterial agents, and has a long-lasting antibacterial effect. The present invention was achieved by discovering that this can be maintained stably.

[Structure of the Invention] The present invention comprises a polymeric foam having antibacterial and antifungal abilities, which contains zeolite holding a metal having a bactericidal effect, and a method for producing the same. Suitable polymers used as polymeric foams in the present invention include polyethylene (PE), polystyrene (Psi, polypropylene (
PP), ethylene-vinyl acetate copolymer (EVA)
, polyvinyl chloride (PCV), acrylonitrile-butadiene-styrene resin (ABS resin), acrylic resin, polyurethane resin (PUR), area resin (UF)
, epoxy resin (EP), phenolic resin (PF)
, nylon, polyvinyl alcohol, viscose or rubber. It goes without saying that these foaming materials may contain plasticizers, stabilizers, fillers, antioxidants, lubricants, colorants, modifiers, etc. without any problem in use. By selecting foaming conditions in consideration of the various material properties mentioned above, and carrying out foaming of a mixture of zeolite that retains metals that have a bactericidal effect (hereinafter referred to as antibacterial zeolite) and a polymer, A foam having an antibacterial function according to the present invention is obtained.

It is desirable that the content of the antibacterial zeolite in the polymeric foam of the present invention be at least 0.03% by weight (anhydrous basis) in order to exhibit desirable antibacterial and antifungal effects. Specifically, the content of antibacterial zeolite in the foam of the present invention is controlled by the type of foam, but it is usually in a desirable range of 0.01 to 10% by weight, and most preferably in a range of 0.03 to 10% by weight. 7% multilayer.

In other words, if the content of antibacterial zeolite is within a range smaller than the latter upper limit, if it is well dispersed within the foam, it will adversely affect the physical properties, strength, etc. of the porous foam itself, causing deterioration. The antibacterial and antifungal functions are maintained sufficiently.

In the present invention, the zeolite suitable as a holding matrix for antibacterial metals is preferably a porous one having an ion exchange capacity of 1 meQ/g (anhydride group Q-) or more and a large specific surface area. A-type,
Preferred examples of olides include clinoptilolite and chaba 1 night. Since the above-mentioned zeolite is contained in a polymer foam, a powdered product with a particle size as small as possible is suitable, and in the present invention, the average particle size (()av
) Activated zeolide powder of 15 μm or less is suitable for uniform dispersion in the foam. It is more preferable that the above-mentioned powder has as little secondary agglomeration as possible.

Next, it is desirable that the cation exchange rate 1 of the above-mentioned zeolite used in the present invention is large, and it is desirable that the above value is at least 1 meQ/min (anhydrous standard) or higher and that the ion exchange rate is high. . By using a zeolide having such characteristics, it is possible to easily prepare an antibacterial zeolite having a predetermined performance by arbitrarily adjusting the amount of one or more antibacterial metal ions retained by an ion exchange method. be.

In the present invention, metals having a bactericidal effect, such as silver (monovalent)
, copper (monovalent or divalent), zinc (divalent), tin (divalent or
Zeolite, which holds one or more metals selected from the group of metals (values) in an ionic state, is contained in the various porous foams mentioned above in a uniformly dispersed state, and this makes it antibacterial. In addition, the mold-proofing function is strongly exhibited throughout the molded article. Generally speaking, the total amount of metals having a bactericidal effect in the zeolite used in the present invention, that is, the total amount of antibacterial metals in the antibacterial zeolite, is 0.00
It is desirable to have a saturated amount (the saturated amount is the saturated value of the ion exchange capacity of the zeolite used) to the saturated amount (5-juken round anhydrous standard). Various foams of the present invention containing antibacterial zeolite within the above range exhibit sufficient antibacterial effects against general bacteria and fungi (molds), as described in the Examples below. Confirmed by antibacterial activity evaluation test.

In general, as seen in the examples, the elution and release of antibacterial metal ions from the porous foam of the present invention is extremely small, and the foam itself is not toxic, so it can be used in a wide variety of applications as described below. It is expected that this will be applied to various fields.

The gist of the method for producing a polymeric foam having antibacterial and antifungal functions according to the present invention is as follows.

Silver is a metal that has a bactericidal effect on porous zeolite with a cation exchange rate of 1 meq/g (anhydrous standard) or more.
After holding one or more metals selected from the metal group of monovalent), copper (monovalent or divalent), zinc (divalent), and tin (divalent or tetravalent) in an ionic state, is activated by heating to reduce its moisture content to 5% by weight or less, and its DaV
The zeolite activated fine powder obtained by adjusting the average particle size to 15μ or less and the polymer are mixed in such an amount that the antibacterial zeolite content is at least 0.03% by weight (anhydrous basis) in the mixture. The present invention provides a method for producing a polymeric foam having antibacterial and antifungal abilities, which comprises mixing the mixture in a uniform ratio, heating the resulting mixture to form a homogeneous mixture, and foaming the resulting mixture. It is something. here,
A two-step method is performed in which a zeolite/polymer masterbatch is prepared in advance by mixing antibacterial zeolite fine powder and a small amount of polymer under heating, and then this is mixed with the remaining polymer and heated. This is also possible as an aspect of the present invention. It is preferable that the antibacterial zeolite used in producing the molded article of the present invention be activated by heat in advance to have a water content of 5% by weight or less. If the moisture content is higher than the above value, cracks, cracks, holes, discoloration, etc. may occur in the foam due to the generation of air bubbles due to the large amount of moisture as the temperature rises, resulting in defective products, so prevent this. Therefore, it is preferable that the water content is 5% by weight or less. Heating is performed using an electric furnace, which varies depending on the type of antibacterial zeolite used, but in normal cases heating is performed at 250° to 500'C (air atmosphere) or reduced pressure heating (150' to 350°C). Therefore, it is possible to easily reduce the moisture content to below the above value. The heat-activated antibacterial zeolite powder is prepared in advance so that its [)ay is 15 μm or less before being mixed with the foaming material to prevent secondary aggregation in the foam as much as possible and improve dispersion. There is a need. This is easily accomplished by crushing or grinding the prepared antimicrobial zeolite. Such prepared antibacterial LA-lye] or an activated fine powder of zeolite prepared as described above, at least 0.03% by weight (obtained by pre-mixing the anhydride group r(u) with the polymeric material under heating). The antibacterial zeolite-polymer-containing body is homogenized by processing it with various foaming materials in the form of powder, particles, sheets, beads, or pellets under heating, and then foamed into various shapes. Of course, the above-mentioned foaming polymer material may contain auxiliary agents, additives, modifiers, colorants, etc. as described above.

In preparing the foam having antibacterial function of the present invention,
Mechanical foaming method that uses inert gas such as carbon dioxide, normal pressure based on the use of organic or inorganic foaming agents that generate gas through thermal decomposition or chemical reaction, or butane, pentane, chlorofluorocarbon gas, etc., press, Foaming methods using extrusion and injection methods, foaming methods using solvent aeration, foaming methods that utilize gas generated during the polymerization or condensation process of polymers,
Sintering foaming method etc. can be used. These foaming methods may be selected in consideration of the physical properties of the foaming polymer used and other factors.

Using the above-mentioned polymer and antibacterial zeolite,
By the method of the present invention, various porous polymer foams having antibacterial and antifungal functions can be obtained. For example, urethane foam with antibacterial ability, PP, PE, PS, ABS,
PVC, EP.

Since various foams such as PVA can be easily obtained, the polymeric foam having antibacterial properties of the present invention can be used in the fields of cosmetic accessories, foods, building materials, industrial materials, etc. that require antibacterial properties. Be expected. Examples include cushioning materials with antibacterial properties, sound absorbers, heat insulators, fish storage containers, and various backing materials.

The main features and advantages of the polymeric foam having antibacterial and antifungal functions of the present invention are summarized as follows.

(a) Since it is a molded article containing inorganic antibacterial zeolite, no deterioration or performance deterioration occurs at all.

(b) Losses due to elution and volatilization of the antibacterial zeolide from the foam are negligible.

(C) The polymer foam of the present invention exhibits an excellent antibacterial effect against general bacteria and molds, and has the advantage that the antibacterial effect is maintained for a long period of time.

(d) The antibacterial foam of the present invention has extremely low toxicity and is almost harmless.

(e) It is effective not only in imparting antibacterial power to the polymer foam itself, but also in antibacterial and sterilizing the atmosphere (gas phase, liquid phase) that comes into contact with it.

(f') In order to achieve the desired antibacterial effect, the amount of antibacterial zeolite used in the polymer foam can be reduced to the amount required for the receiving gutter.

(g) This zeolite-based antibacterial agent is thermally stable, and even if it is dispersed into a polymeric foam under heating, the amount within the usage range of the present invention will not cause any deterioration of the foam or decrease in antibacterial activity. I don't.

(h) The antibacterial activity of the antibacterial foam of the present invention changes little over time.

Next, embodiments of the present invention will be described with reference to Examples, but the present invention is not limited to these Examples. The mold resistance evaluation test shown in the examples of the present invention is based on ASTM G-
The test was conducted in accordance with No. 21 test method. The composition of the medium is KH2PO4C0,7'i), K2HPO4(0,
7';i), Mg304・7H20 (0.7g>
, NH4NO3 ('1.0g), Na C,l! (0
,0059>, Fe 5o4-7 H20(0,00
2g), Zn 804-7H2o (0,002g>,
Mn SO4-7H20 (0,001y > , agar (
A medium consisting of 15y> and 1000d of pure water was used. Aspergillus nig was used as a test bacterium.
cr (ATCC9642), Penicill
ium funiculosum (ATCC9644)
, Chaetomium globosum (AT
CC6205), Trichoderma, T
-1 (8TCC9645), and ^ureobas
idium pullulans (ATCC9348)
A mixture of these bacteria was inoculated using five species. Cultivation was carried out for 30 days at relative humidity (R, H,) of 85 to 95%, and the test results were evaluated in the following five stages.

0 No slow growth 1 Slight growth (10% or less) 2 Slight growth (10-30%) 3 Intermediate growth (30-60%) Furthermore, in relation to the evaluation of antibacterial activity, bacterial and fungal Mortality measurements were carried out using the foams of the invention and were carried out in the manner described below.

i> Bacterial strain used: 8 supergillus niger IFO4407
(Black koji mold) Staphylococcus aure
us IFO12732 (Staphylococcus aureus) ii) Preparation of spore suspension After aspergillus Aspergillus forms sufficient spores in the preculture medium, the spores are suspended in 0.005% dioctyl sulfone sodium succinate solution and added to sterile physiological saline. It was diluted with water to a concentration of about 10"/d, and this was used as a spore suspension.

1ii) Preparation of Bacterial Solution Staphylococcus aureus was cultured overnight at 35° C. in an ordinary bouillon medium, and then diluted appropriately with sterile physiological saline to prepare an inoculum solution.

iV) Test procedure (a) Black koji mold: A spore suspension was sprayed onto the test piece until the surface was sufficiently wet. The test piece immediately after spraying and the test piece after being sealed and stored at 30°C for 48 hours were extracted with 20% Tween 80 sterilized physiological saline, and the number of molds in this extract was counted using Sabouraud agar medium at 25°C. After culturing for 7 days, the number of molds per test piece was calculated.

(b) Staphylococcus aureus: Place the test piece in sterile physiological saline 4
The mixture was placed in an Erlenmeyer flask containing 0me, and the inoculum solution was added thereto at a concentration of 104 per 1 d.

This Erlenmeyer flask was shaken at 30°C, and the number of viable bacteria immediately after inoculation and 48 hours later was determined using 5CDLP agar medium.
After culturing at 5°C for 2 days, measurements were taken.

Example 1 Example 1 relates to the preparation of polyethylene foam (PE) having antibacterial and antifungal functions of the present invention and its antibacterial activity. Antibacterial zeolite activated powder (Dav=2.7
．． czm; 320°C heating activation: Na AgCu
Z type (Z = A type zeolite matrix, A (+ = 4.90
%: Cu = 7.85% Nicho 0 = 3.19%)] and LDPE (Ube Industries product name J3519, MI = 35
, density = 0.919) were heated and mixed at 230° C. or lower to prepare a masterbatch Na A (CI Z-LDPE molded pellets). The above masterbatch and LD
Blend a certain amount of PE into an extrusion foaming machine and raise the temperature to 21
The mixture was melted and mixed at around 0° C., and extruded through a nozzle while introducing butane as a foaming gas to produce an LDPE network foam containing about 1% of NaAgCuZ as shown in FIG. Cut this mesh foam to approximately 80x5
Using a 0g++ test piece, an evaluation test for antibacterial activity was conducted by the method described above. Table 1 shows the PEN-4 test piece of the above shape (Na ACl CD Z-type antibacterial agent containing material: 8 g =
5 taphylococcus au as a typical bacterium with 0.0435%; CO = 0.104%>
This figure shows the results of testing the antibacterial effect against S. reus. The number of bacteria in the test solution was 48 for PEN-4.
As time passed, almost O was reached with only 4 pieces/d,
On the other hand, in PEN-BL, which has the same shape as PEN-4 (blank test: PE net approx. 80 It was. From the comparison of both tests, it is clear that the antibacterial net of the present invention has an excellent effect on bacteria.

Table 1 5taphy+ococcus in 1d of test solution
aureus (Staphylococcus aureus) several 0 hours 48 hours PEN-BL 4.2X10 3.8X103
*AQ = 0.0435%; Cu = 0.10
4%; Antibacterial zeolite: NaAgCuZ type Next, Table 2 shows the change over time in the amount of antibacterial metal eluted from the PE net obtained in Example 1. For the elution test, a test piece having a size of approximately 50 x 125 m was prepared by cutting 1q of nets in Example 1 (weight of test piece was approximately 0.59).

Tap water (Ca 2+ = 3.tppm) was added to the above test piece.
; Mg=3.6ppfn; C,ll=4pp
m; ptl=7.03) as a test piece (PEN-1>
1y/) (water flow). Next, the above-mentioned mixed solution was stirred from time to time, and the time-dependent change in the metal eluted into the aqueous phase was measured over 1000 hours, and the results shown in Table 2 were obtained. As shown, the elution amount of copper and silver, which are antibacterial metals, is 0 to 0.
After 1000 hours, the amount of "C-" is a very small amount of 10 ppb or less. Such elution amount is completely harmless and is a preferable value.

Table 2 Antibacterial metal elution test piece from foamed polyethylene net: 50x 125In! ! IP E-net (A
O = 0.0435%; CIJ -0,104%) Test piece Antibacterial metal Elapsed time (hours) number (
ppb) 10 100 500 100OPE
N-1 copper 2.8 3.1 4.0 9
．． 5 silver 0.5 0.7 1.3 3.2
pH of aqueous phase approximately 7, O; antibacterial zeolite diNa A
! II COZ Type Example 2 Example 2 describes urethane foam as an example of the polymer foam having antibacterial and antifungal functions of the present invention. In this example, both ether type and ester type urethane (PtJR) are used, and NaAgZn
Foams containing 0.1-5% of Z-type antibacterial zeolite were made. Antibacterial zeolites include Na A (II Zn
Z-type activated powder (heat activated at 330°C: Dav-
2, lμTrt: H20 = 2.6%) using
A mixture of this and PUR rope material was foamed to produce PUR ether type and ester type foams.

A mold resistance test was carried out by cutting a PUR foam containing q%7 into a soxsog shape and inoculating a mixture of five molds according to the ASTM G-21 test method described above. The results are listed in Table 3. PUR foot
-um (ether type) test pieces U-28, 29 and 30
(AD = 0.011-0.118%; zn = 0.0
062-0, 065%), no mold growth was observed and a favorable evaluation of O was obtained.

U-BL-16 and U-BL-2 are both comparative examples (blank test). The former is a PUR plate (ether type) with a shape of 50x50#, and the latter is a 50x50WII! The antibacterial zeolite was not added to any of the test specimens. These mold resistance ratings were 3 and 2, respectively, and it was confirmed that a considerable amount of mold grew. PUR according to the invention
In the foam (ester type) mold resistance test, U-3
5 and 36 (A (J = 0.011-0.024%; 7
-n = 0.078 to 0.130%), the evaluation symbol is O, and no development of force was observed at all, while the U-31 test piece (Ag = 0.002
%; Zn = 0.040%), slight mold growth was observed. P having antibacterial ability of the present invention listed in Table 3
From a comparison of the UR foams (ether type and ester type) and comparative examples, it is clear that the foams of the present invention have extremely high mold resistance.

Table 3 [Mold resistance test test piece of Fretan molded product Niblate and foam A--(50x50m>(ether type) Without CI-BL-2 Added foam
Second, Table 4 shows an example of the antibacterial activity test of the foam of the present invention against common bacteria. By the method described above, ESCheriChi per 1rIIIl of the test solution after a certain period of time has elapsed.
The number of B. acoli was measured, and from this the killing rate of the bacteria was calculated. For test specimens U-28 and U-29 (PUR form; ether type), ESCheriChia c
The mortality rate of Oli was 100% after 24 and 48 hours, and exactly the same favorable results were obtained with test piece U-35 (PUR form; ester type). Furthermore, using test piece U-35, by the method described above,
Aspergillus per 1 d of test solution after a certain period of time
The number of S. niger was measured and it was confirmed that it decreased significantly after 24 hours.

It is clear from Tables 3 and 4 that the foam of the present invention not only has high mold resistance, but also has strong antibacterial activity against common bacteria.

Table 4: Mortality rate measurement sample number Escher 1chla col! Mortality rate against (¥,) U -28100 LJ -29100 U -35100

[Brief explanation of drawings]

The figure shows the shape of the PE foam (net) of the present invention made in Example 1. Applicant Shinagawa Fuel Co., Ltd. Kanebo Co., Ltd. Kusan Paper Co., Ltd. Hagiwara Giken Procedural Amendments June 22, 1985

Claims (1)

[Scope of Claims] 1) A polymeric foam having antibacterial and antifungal functions and containing zeolite that retains a metal having a bactericidal effect. 2) The polymeric foam having antibacterial and antifungal functions according to claim 1, wherein the content of zeolite retaining a metal having a bactericidal action is at least 0.03% by weight (anhydrous basis). 3) Claim 1 comprising a zeolite that holds one or more metals selected from the group consisting of silver, copper, zinc, and tin in an ionic state as metals having a bactericidal effect. A polymeric foam having antibacterial and antifungal functions according to item 1 or 2. 4) The polymer according to any one of claims 1 to 3, wherein the total amount of metals having a bactericidal effect in the zeolite is in the range of 0.005% by weight (anhydrous basis) to a saturated amount. foam. 5) The zeolite is a natural or synthetic zeolite with an ion exchange capacity of 1 meq/g (anhydrous standard) or more, and has antibacterial and antifungal functions as described in any one of claims 1 to 4. Polymer foam. 6) The polymer foam having antibacterial and antifungal functions according to any one of claims 1 to 5, wherein the zeolite is an activated powder of zeolite with an average particle size of 15 μm or less. 7) The polymer is polyethylene, polystyrene, polypropylene, ethylene vinyl acetate copolymer, polyvinyl chloride, acrylonitrile-butadiene-styrene resin, acrylic resin, polyurethane, area resin, epoxy resin,
The polymeric foam according to any one of claims 1 to 6, which is a phenolic resin, nylon, polyvinyl alcohol, viscose, or rubber. 8) A zeolite with an ion exchange capacity of 1 meq/g or more (anhydrous standard) retains a bactericidal metal, and then heat activates it to reduce the water content to 5% by weight or less, and the average particle size to 15 μm or less. The zeolite-activated fine powder obtained by adjusting the zeolite and the polymer are mixed in a quantitative ratio such that the content of the zeolite is at least 0.03% by weight (anhydrous basis) in the mixture, and then the obtained A method for producing a polymeric foam having antibacterial and antifungal functions, which comprises heating a mixture to form a homogeneous mixture and then foaming the mixture. 9) Polymers include polyethylene, polystyrene, polypropylene, ethylene-vinyl acetate copolymer, polyvinyl chloride, acrylonitrile-butadiene-styrene resin, acrylic resin, polyurethane, area resin, epoxy resin, phenol resin, nylon, polyvinyl alcohol,
9. The method according to claim 8, wherein the material is viscose or rubber.