KR960006791B1 - Antibacterial and anti-mold polyolefin resin molding articles and the process thereof - Google Patents

Abstract

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Description

Antibacterial and anti-bearing polyolefin resin molded article and preparation method thereof

The present invention relates to an antibacterial and antifungal polyolefin resin molded article and a method for producing the same, and more particularly, to an antibacterial and antifungal mold containing a fired product of an antibacterial calcium-based ceramics, in particular an antimicrobial hydroxyapatite. The present invention relates to a polyolefin-based resin molded article and a method for producing the same.

Plastics have been considered to be resistant to microorganisms such as molds and bacteria, but recently, damages caused by these microorganisms have been reported, and antimicrobial treatments have been required according to their use. As an antimicrobial treatment, it is considered to add a fungicide to the plastic, but in general, the fungicide is weak against heat because the organic compound is used a lot, and may be deteriorated due to the plastic processing temperature and thus the disinfectant may be lost. Hard to use

Plastics, plasticizers, stabilizers, fillers, lubricants, and other organic chemicals are used in combination to maintain their properties. The filler is used as a reinforcing material or weighting agent, and calcium carbonate, talc, diatomaceous earth, and other inorganic substances are used, and instead of organic fungicides, it is considered to impart antimicrobial properties to plastics by acting inorganic fungicides. For example, Japanese Patent Application Laid-Open No. 62-241939 describes an antimicrobial polyolefin resin molded article containing a zeolite (hereinafter referred to as an antimicrobial zeolite) in which a metal having an antimicrobial effect on a polyolefin resin is retained. . Since the antimicrobial zeolite retains the antimicrobial metal on the zeolite, which is an ion exchanger by ion exchange, it does not lose its activity at the temperature at the time of molding, but depending on the water content, bubbles are generated at the molding temperature to generate air bubbles, and thus the polyolefin resin molding Since the properties are lost, the antimicrobial zeolite needs to be sufficiently dehydrated and used. In addition, in order to obtain a homogeneous mixture with the polyolefin resin, the pulverized antimicrobial zeolite is first homogeneously treated with a small amount of polyolefin resin at a temperature of 300 ° C. or lower. A complicated process of obtaining a mixed radish, which is dispersed (called premixing), and mixing and molding the polyolefin resin again is recommended. However, since the zeolite is considered to be physically unstable with the amine moiety as the ion exchanger, heat treatment requires special attention, and in order to maintain the antimicrobial metal by ion exchange, the amount of the zeolite used is the ion exchange capacity of the zeolite used. And the processing method thereof. On the other hand, since antimicrobial activity is considered to depend on the storage amount of the antimicrobial metal, the selection of the raw material zeolite to be used and its treatment method are important factors for the production of the antimicrobial zeolite. Therefore, Japanese Patent Laid-Open No. 62-241939 describes the type of raw material zeolite to be used, the water content and the amount of the antimicrobial zeolite to be used, and describes the use of the obtained antimicrobial zeolite by heat activation.

The polyolefin resin mixture containing the antimicrobial zeolite is also stable in the molding process, so that the contained antimicrobial metal is less eluted, the antimicrobial power is lowered, the quality deterioration is less likely to occur, and an excellent molded product is obtained. There is no elution at all, but a small amount of elution causes the molded body to deteriorate with prolonged use. For example, an antimicrobial polyolefin resin molded article containing an antimicrobial zeolite using silver as an antimicrobial metal causes discoloration when subjected to sunlight for a long time. In addition, since the production of the antimicrobial zeolite is subject to the same limitations as described above, the production of the antimicrobial polyolefin resin molded article containing the antimicrobial zeolite can be a fairly difficult process.

In the present invention, instead of the antimicrobial zeolite, the elution of the antimicrobial metal is considerably smaller than that of the antimicrobial zeolite, hardly elutes, the antimicrobial power can be arbitrarily selected, the dispersion into the polyolefin resin is good, and no premixing is required. Another object of the present invention is to provide an antimicrobial and antifungal polyolefin resin molded product using an inorganic antimicrobial agent which is easy to synthesize, and a method of manufacturing the same.

In order to solve the above problems, in the present invention, instead of the antimicrobial zeolite, it is proposed to use a fired product at a high temperature, preferably 800 ° C. or higher, of the antimicrobial calcium-based ceramics, particularly the antimicrobial hydroxyapatite, on which an antimicrobial metal is supported.

Antimicrobial calcium ceramics used in the present invention, for example, the salt of the antimicrobial metal is supported on the calcium ceramics in a conventional manner such as adsorption or ion exchange, or calcium-based ceramics in the coexistence of these metal salts conventional methods After being produced, the product can be easily obtained by firing at a high temperature, preferably 800 ° C or higher. The antimicrobial metal to be used is selected from silver, copper and zinc, but in particular the use of silver and zinc is preferred, and the calcium-based ceramics are selected from calcium phosphate, calcium carbonate, calcium silicate and hydroxy apatite, in particular of hydroxyapatite Use is preferred. Hydroxyapatite has a composition of Ca ₁₀ (PO ₄ ) ₆ (OH) ₂ , is a major component of bone and teeth, absorbs proteins and lipids in weak alkalinity (PH 7-9), and has affinity with biological components. It is recognized as being good and having ion exchange capacity. However, the synthesis from calcium salts and phosphates of hydroxyapatite having a stoichiometric molar ratio of Ca / P of 10/6 is uneconomical because it involves a certain kind of difficulty. On the other hand, the synthesis of hydroxyapatite analogues having a molar ratio of Ca / P of 1.4 to 1.8 from calcium salts and phosphates is easy and it should be interpreted that these analogues are also included in the term hydroxyapatite. The amount of the metal supported on the calcium-based ceramics is arbitrarily selected within the range of adsorption or ion exchange, but it is 50% by weight or less, preferably 0.001-30 wt. %, More preferably 0.01 to 10% by weight. The antimicrobial calcium ceramics thus obtained are fired at a high temperature, preferably 800 ° C. or higher, and finely pulverized, preferably to an average particle diameter of 10 μm or less, and dispersed in a polyolefin resin. Since the antimicrobial calcium ceramics of the present invention are fired at a high temperature, the supported metal is strengthened to bond with the ceramics, and the ceramics itself shrinks and stabilizes by firing, so that metals are not eluted from the ceramics and mixed and dispersed into the polyolefin resin. It is also easy and both raw materials and processing methods are simple compared to the preparation and use of antimicrobial zeolites.

Polyolefin resins described in the present invention include polyethylene, polypropylene, propylene copolymers, ethylene lower α-olefin copolymers and ethylene copolymers, but these resins are mixed with various additives and widely used according to their performance. . However, microorganisms are easily contaminated by containing such additives. Therefore, it is preferable to contain antimicrobial calcium-based ceramics in these polyolefin resins as a defense against microbial contamination. In other words, when the antimicrobial calcium-based ceramics are molded by mixing at least 0.03% by weight based on the resin, the molded body is not contaminated by microorganisms. The upper limit of the mixing ratio of the antimicrobial calcium-based ceramics is arbitrarily determined by the starch agent of the desired resin molding, but generally up to about 10% by weight is sufficient. These mixed moldings may be mixed molding after premixing as in the case of mixing the antimicrobial zeolite, but may be directly mixed with the resin.

Thus, the polyolefin resin molded body obtained by molding the polyolefin resin material containing the antimicrobial calcium ceramics by a conventional method has no elution of the antimicrobial metal compared to the antimicrobial zeolite-containing polyolefin resin molded body, and thus does not deteriorate for a long time. While being used safely, it is easier to change the antimicrobial activity in a wider range than the antimicrobial zeolite content resin molded body.

Next, an Example is described and this invention is demonstrated concretely.

(Example 1)

Preparation of Used Antimicrobial Calcium Ceramics

(Example 1-1)

Preparation of Antimicrobial Hydroxyapatite

10 kg of hydroxyapatite, 32 g of silver nitrate, and 69 g of zinc nitrate are added to distilled water 10ι and stirred. The product was washed well with distilled water, dried, calcined at 1,200 ° C., and then ground to obtain an antimicrobial hydroxyapatite carrying about 2% silver and about 1.5% zinc (1-1).

(Example 1-2)

Preparation of Antimicrobial Tricalcium Phosphate

1.0 kg of tricalcium phosphate, 30g of silver nitrate, and 45g of zinc nitrate are added to 10ι of distilled water and stirred. The product was washed well with distilled water, dried, calcined at 1,100 ° C., and then ground to obtain an antimicrobial tricalcium phosphate supporting about 0.5% silver and about 1% zinc (1-2).

(Example 1-3)

Preparation of Antimicrobial Calcium Carbonate

1.0 kg of calcium carbonate and 0.01 g of silver nitrate are added to 10ι of distilled water and stirred. The product was washed well with distilled water, dried, calcined at 800 ° C., and then ground to obtain an antimicrobial calcium carbonate loaded with 0.0001% silver (1-3).

(Example 1-4)

Preparation of Antimicrobial Calcium Silicate

1.0 kg of calcium silicate, 180 g of silver nitrate, and 200 g of copper nitrate are added to distilled water, and the mixture is stirred while boiling. The product was washed well with distilled water, dried, calcined and ground at 1,200 ° C. to obtain antimicrobial calcium silicate carrying about 10% silver and about 5% copper (1-4).

(Example 2)

Metal ion dissolution test

100 g of distilled water was added to 1 g of each of the antimicrobial calcium ceramics obtained in Examples 1-1 to 1-4 and a dehydrated product of commercial antimicrobial zeolite containing silver and zinc (called A), followed by stirring for 30 minutes, Atomic Absorption Spectrophotometer is used to measure the metal ions in the solution and calculate the elution amount.

In the table Indicates that it is below the detection limit.

The metal leaching amount of calcined antimicrobial calcium-based ceramics is significantly smaller than that of the antimicrobial zeolite.

(Example 3)

Discoloration test

(1) calcined antimicrobial zeolite and carrier zeolite carrying 1 wt% silver; The zeolite with 1% by weight of silver ion-exchanged and the carrier zeolite were left indoors for 6 months to measure the change in white color.

Discoloration test result

From the above result, it turns out that it does not discolor at all even if silver containing hydroxyapatite (containing 1% of silver) is left for 6 months indoors. Moreover, in silver containing zeolite which elutes Ag ion slightly, discoloration is severe and whiteness falls largely.

(Example 4)

Production of Polyethylene Resin Molded Products

An average of 10 μm or less of the antimicrobial calcium-based ceramics prepared in Examples 1-1 to 1-4 was mixed so as to be 5% by weight based on low density polyethylene, and the mixture obtained by treating at about 185 ° C. in a brabender was 180. Pressurized at 43 kg / cm 2 for 2 minutes at < RTI ID = 0.0 > C, < / RTI > This disc is cut into 5 x 5 cm and used for the next antimicrobial test. In addition, except that the antimicrobial zeolite used in Example 2 was used instead of antibacterial calcium-based ceramics, the antimicrobial zeolite-containing polyethylene resin molded body obtained by the same operation as Example 4 was prepared and used as a comparative example.

(Example 5)

Antibacterial and Mildew Test

(1) Antibacterial test

Using E. coli as a bacterium, E. coli bacteria are sprayed onto the surface of a 5 x 5 cm 2 molded product, and cultured for 24 hours to measure antibacterial activity.

In the table 1 indicates that it is below the limit of bacterial counting.

Sample 1-1 means that the antimicrobial calcium-based ceramics-containing molded article prepared in Example 1-1.

(2) mold prevention test

Using Aspergillus sniger as a mold, sprayed on the surface according to the antimicrobial test, incubated for 24 hours, and then the mold was extracted from the test piece, and the number of molds in the extract was measured in a conventional manner to prevent mold development. Confirm that it is not.

(Example 6)

Discoloration test of polyethylene resin molded body

The molded article obtained in Example 4 containing the antimicrobial hydroxyapatite obtained in Example 1-1 (Sample 1-1) and the molded article obtained in Example 4 for comparison (Comparative Example) were each 5 x 5 x 0.5. Cut into cm 2 and exposed to sunlight for 6 months. Discoloration is not seen after 6 months in sample 1-1, but the comparative example is black and clear discoloration is confirmed.

Instead of antimicrobial zeolites, antimicrobial and mold-resistant polyolefin resin moldings made using antimicrobial calcium-based ceramics have no dissolution of antimicrobial metals. Compared with the preparation of the antimicrobial zeolite, a molded article having a simple and arbitrary antibacterial power can be easily obtained.

Claims (7)

The polyolefin resin is mixed with a fired product of antimicrobial calcium ceramics in which at least one antimicrobial metal selected from the group consisting of silver, copper and zinc is supported on calcium ceramics selected from calcium phosphate, calcium carbonate, calcium silicate and hydroxyapatite. An antibacterial and antifungal polyolefin resin molded product characterized by the above-mentioned. The resin molding according to claim 1, wherein the calcium-based ceramics are hydroxyapatite. The resin molded body according to claim 1, wherein the content of the antimicrobial metal in the antimicrobial calcium ceramics is 0.01% by weight to 10% by weight of the antimicrobial calcium ceramics. The resin molded body according to claim 1 or 2, wherein the content of the antimicrobial calcium-based ceramics is 0.03% by weight or more based on the molded body. One or more antimicrobial metals selected from silver and copper and zinc are supported on calcium-based ceramics selected from calcium phosphate, calcium carbonate, calcium silicate and hydroxyapatite, and then the ceramics are calcined at 800 ° C. or higher, and the fired product has an average particle size of 10 μm. A method for producing a polyolefin resin molded article comprising pulverizing below and mixing the obtained fine powder with the polyolefin resin so that the content of the fine powder is 0.03% by weight or more. The resin molded body according to claim 2, wherein the content of the antimicrobial metal in the antimicrobial calcium-based ceramics is 0.01 wt% to 10 wt% of hydroxyapatite. The resin molded body according to claim 3 or 6, wherein the antimicrobial calcium-based ceramics content is 0.03% by weight or more based on the molded body.