JPH04142349A - Antibacterial and fungicidal polyolefin rein molding and preparation thereof - Google Patents

Abstract

PURPOSE:To prepare the title molding usable safely for a long term and having a widely changeable antibacterial power by depositing an antibacterial metal on a calcium ceramic, backing and powdering the ceramic, compounding the powdered ceramic into a polyolefin resin, and molding the resulting compsn. CONSTITUTION:On a calcium ceramic selected from the group consisting of calcium phosphate, calcium carbonate, calcium silicate, and hydroxyapatite an antibacterial metal selected from the group consisting of silver, copper, and zinc. is deposited. The ceramic is then backed at 800 deg.C or higher and powdered into particles with a mean particle size of 10mum or lower. A polyolefin resin is compounded with the ceramic powder in an amt. of at least 0.03wt.% based on the resulting compsn., and molded to give the title molding. As the metal, silver and zinc are esp. pref., and an esp. pref. calcium ceramic is hydroxyapatite.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a polyolefin resin molded article having antibacterial and antifungal properties and a method for producing the same. The present invention relates to a polyolefin resin molded article having antibacterial and antifungal properties containing a fired product of calcium ceramics, particularly antibacterial hydroxyapatite, and a method for producing the same.

(Prior art) Plastics were thought to be resistant to microorganisms such as mold and bacteria, but recently there have been reports of damage caused by these microorganisms, and depending on their use, antimicrobial treatment is required. It has become necessary. As an antimicrobial treatment, adding disinfectants to plastics can be considered, but since disinfectants generally contain many organic compounds, they are sensitive to heat and may deteriorate due to plastic processing temperatures and lose their bactericidal properties. Therefore, it is difficult to use organic disinfectants on plastics.

Plastics are mixed with plasticizers, stabilizers, fillers, lubricants, and other organic agents to maintain their properties.

Fillers are used as reinforcing materials or extenders, and calcium carbonate, talc, diatomaceous earth, and other inorganic substances are used, so instead of organic fungicides, inorganic fungicides act to impart antimicrobial properties to plastics. That is what is being considered. For example, Japanese Patent Application Laid-Open No. 62-241939 discloses an antibacterial polyolefin resin molded article in which a polyolefin resin contains zeolite (hereinafter referred to as antibacterial zeolite) in which a metal having an antibacterial effect is retained. Antibacterial zeolite is made by retaining antibacterial metals in zeolite, which is an ion exchanger, through ion exchange, so it will not be deactivated at the temperature during molding, but depending on the water content, bubbles due to water vapor may be formed at the molding temperature. The antibacterial zeolite must be thoroughly dehydrated before use, as this can damage the properties of the polyolefin resin molded product. We are proceeding with a complex process in which a small amount of polyolefin resin is treated at a temperature below 300°C to obtain a homogeneously dispersed mixture (referred to as premixing), which is then mixed and molded with polyolefin resin. However, since zeolite uses an amine acid group as an ion exchange group and is recognized to be physically unstable, special care must be taken during heat treatment. The amount retained varies depending on the ion exchange capacity of the zeolite used and its processing method. On the other hand, since its antibacterial properties are thought to depend on the amount of antibacterial metals retained, the selection of the raw material zeolite to be used and its treatment method are important factors in the production of antibacterial zeolite. Therefore, JP-A-62-241939 specifies the type of raw material zeolite to be used, the water content and amount of antibacterial zeolite used, and describes that the obtained antibacterial zeolite is used after being activated by heat.

(Problem B to be solved by the present invention) The polyolefin resin mixture containing antibacterial zeolite is stable during molding treatment, and the contained antibacterial metals are less likely to be eluted, resulting in a decrease in antibacterial activity and quality deterioration. Although it may be difficult to replace the molded product with excellent quality, the elution of antibacterial metals will still occur, albeit in small amounts.
If used for a long period of time, the quality of the molded product will change. For example, an antibacterial polyolefin resin molded article containing antibacterial zeolite using silver as an antibacterial metal will discolor if exposed to sunlight for a long period of time. Furthermore, since the production of antibacterial zeolite is subject to the above-mentioned restrictions, the production of antibacterial polyolefin resin molded articles containing antibacterial zeolite must involve considerably difficult steps.

The present invention replaces antibacterial zeolite I with antibacterial metals that elute significantly less than antibacterial zeolite (almost no elution), allows the antibacterial activity to be selected arbitrarily, and disperses antibacterial metals in polyolefin resins. It is an object of the present invention to provide an antibacterial and antifungal polyolefin resin molded article using an inorganic antibacterial substance that has good antibacterial properties, does not require premixing, and is easy to synthesize, and a method for producing the same.

(Means and effects for solving the problems) In order to solve the above problems, in place of antibacterial zeolite, antibacterial calcium-based ceramics supported with antibacterial metals, especially antibacterial hydroxyapatite, can be used at high temperatures. 800
The present invention proposes the use of a product fired at a temperature higher than "C".

The antibacterial calcium-based ceramics used in the present invention are
For example, a metal salt having antibacterial properties is supported on calcium-based ceramics by adsorption or ion exchange using a conventional method, or calcium-based ceramics are formed by a conventional method in the coexistence of these metal salts, and then heated at a high temperature, preferably 800°C. It can be easily obtained by firing at a temperature of 'C or higher. The antibacterial metal used is selected from silver, copper and zinc, with silver and zinc being particularly preferred, and the calcium-based ceramic being selected from calcium phosphate, calcium carbonate, calcium silicate and hydroxyapatite, particularly hydroxyapatite. is preferred. Hydroxyapatite is Ca, o (PO4) b (OH)
It has a composition of z, is a product of bones and teeth, and is slightly alkaline (
It has been recognized that it adsorbs proteins and lipids well at pH 7-9), has good affinity with biological components, and has ion exchange ability. However, the synthesis of hydroxyapatite having the above-mentioned stoichiometric molar ratio of Ca/P=10/6 from calcium salts and phosphates is not economical due to certain difficulties. On the other hand, Ca/p = 1.4~1
．． Synthesis of hydroxyapatite analogs with a molar ratio of 8 from calcium salts and phosphates is easy;
These types (U) can be used in the present invention as well as hydroxyapatite, so these analogs should also be understood to be included in the term hydroxyapatite.The amount of metal supported on calcium-based ceramics depends on the adsorption Alternatively, it can be selected arbitrarily within the range of ion exchange, but from the viewpoint of maintaining the structure of the calcium-based ceramic carrier and antibacterial activity, it is less than 50% by weight of the ceramic, preferably 0.00%.
It is 1 to 30%, more preferably 0.01 to 10%. The antibacterial calcium-based ceramic thus obtained is fired at a high temperature, preferably at 800°C or higher, and it is pulverized as finely as possible, preferably to an average particle size of 10 μm or less, and dispersed in a polyolefin resin. use. Since the antibacterial calcium-based ceramics of the present invention are fired at high temperatures, the bond between the supported metal and the ceramics is strengthened, and the ceramic itself shrinks and stabilizes due to firing, so metals do not elute from the ceramics. It is easy to mix and disperse into polyolefin resins, and both raw materials and processing methods are simpler than those for producing and using antibacterial zeolites.

The polyolefin resin referred to in the present invention includes polyethylene, polypropylene, propylene copolymer, ethylene lower α-olefin copolymer, and ethylene copolymer, and these resins can be mixed with various additives,
Due to its performance, it is widely used. However, the inclusion of these additives makes it susceptible to microbial contamination. Therefore, incorporating antibacterial calcium ceramics into these polyolefin resins is more effective in preventing microbial contamination. That is, if at least 0.03% of the weight of the resin is mixed with antibacterial calcium-based ceramics and molded, the molded product will not be contaminated by microorganisms.

The upper limit of mixing of antibacterial calcium ceramics is arbitrarily determined depending on the properties of the intended resin molded product, but mixing up to about 10% is generally sufficient. These mixture moldings may be carried out after premixing, as in the case of mixing antibacterial zeolite, but they can also be mixed and molded directly with the resin.

A polyolefin resin molded article obtained by molding a polyolefin resin material containing antibacterial calcium-based ceramics as shown in 2. Since there is no elution, there is no deterioration over a long period of time, making it safe to use, and it is easier to vary the antibacterial activity over a wider range than with antibacterial zeolite-containing resin moldings.

EXAMPLES The present invention will be specifically described below with reference to Examples.

■Top.

Production example 1-1 of the antibacterial calcium-based ceramics used. Production of antibacterial hydroxyapatite 101
Hydroxyapatite in distilled water 1. OR1 silver nitrate 3
Add 2g of zinc nitrate and 69g of zinc nitrate, and stir. The product was thoroughly washed with distilled water, dried, calcined at 1.200°C, and ground to obtain antibacterial hydroxyapatite carrying about 2% silver and about 1.5% zinc (1-1).

Example 1-2 Production of antibacterial tricalcium phosphate 1.0 kg of tricalcium phosphate and 30 g of silver nitrate in 1042 distilled water
, add 45 g of zinc nitrate and stir.

The product was thoroughly washed with distilled water, dried, calcined at 1,100"C, and ground to obtain antibacterial tricalcium phosphate carrying about 0.5% silver and about 1% zinc (1- 2) Example 1-3.
Preparation of antibacterial calcium carbonate 1.0 kg of calcium carbonate and 0.01 g of silver nitrate are added to 101 liters of distilled water and stirred. The product was thoroughly washed with distilled water, dried, calcined at 800''C, and ground to obtain antibacterial calcium carbonate carrying 0.0001% silver (1-3).

Example 1-4. Production of antibacterial calcium silicate 1.0 kg of calcium silicate, 180 g of silver nitrate, and 200 g of copper nitrate are added to the distilled water of step 102, and the mixture is stirred while boiling. The product was washed with distilled water, dried, calcined at 1 and 200°C, and ground to obtain an antibacterial calcium silicate carrying about 10% silver and about 5% copper (1-4).

Example 2. Add Ig of each of the antibacterial calcium-based ceramics obtained in Metal Ion Elution Test Examples 1-1 to 1-4 and the dehydrated product (denoted as A) of a commercially available antibacterial zeolite containing silver and zinc to 100 g of distilled water.
After stirring for 30 minutes, metal ions in the solution were measured using an atomic absorption spectrometer, and the amount eluted was determined.

The values in the table indicate that the values are below the detection limit.

The results show that the amount of metal eluted from the fired antibacterial calcium-based ceramics is significantly lower than that from the antibacterial zeolite.

Example 3. Discoloration test (1) Calcined antibacterial zeolite and carrier zeolite carrying 1% by weight of silver; Zeolite and carrier zeolite with 1% by weight of silver ion-exchanged were each left indoors for 6 months, and changes in their white color were measured.

Discoloration test results Based on the above results, silver-containing hydroxyapatite (silver,
1%) was left indoors for 6 months without any discoloration. In addition, in the silver-containing zeolite that slightly elutes Ag ions, discoloration was severe and a large decrease in whiteness was observed.

Example 4. Production of polyethylene resin molding Example 1: 5% by weight of low density polyethylene
The antibacterial calcium-based ceramic particles prepared in steps 1 to 1-4 with an average size of 10 μm or less were mixed and treated with a plastic bender at about 185°C.
It was pressurized at 43 kg/ct [' for 2 minutes at 'C' and formed into a φ20 cm disc (thickness lIr1l'fi).

This disk was cut into 5 x 5 cm and used for the following antibacterial test. For comparison, an antibacterial zeolite-containing polyethylene resin molded body was prepared in the same manner as in Example 4, except that the antibacterial zeolite used in Example 2 was used instead of the antibacterial calcium ceramic. used.

Example 5. Antibacterial and antifungal test (1) Antibacterial test Escherichia coli was used as the bacteria, and an Escherichia coli solution was sprayed onto the surface of a 5 x 51 molded product, cultured for 24 hours, and its antibacterial activity was measured.

In the table, <1 indicates that the bacterial count was below the limit.

Sample 1-1 means a molded article containing antibacterial calcium-based ceramics manufactured according to Example 1-1.

(2) Anti-mold test Using Aspergillus niger as the mold, spray it on the surface according to the antibacterial test, and after culturing for 24 hours, extract the mold from the test piece and measure the number of molds in this extract using the usual method. It was acknowledged that no mold growth was observed.

Example 6. Discoloration Test of Polyethylene Resin Molded Body The molded body obtained in Example 4 containing the antibacterial hydroxyapatite obtained in Example 1-1 (Sample 1-1) and the molded body obtained in Example 4 for comparison (Comparative Example) were each 5X5X0 It was cut into .5cTA and exposed to sunlight for 6 months. Although sample 1-1 showed no discoloration after 6 months, clear darkening and discoloration were observed in the comparative example.

(Effects of the invention) Antibacterial and antifungal polyolefin resin molded products made using antibacterial calcium ceramics instead of antibacterial zeolite do not elute antibacterial metals, so they are safe and long-lasting without deterioration due to metals. In addition to being usable for a long period of time, the production of antibacterial calcium ceramics is simpler than the production of antibacterial zeolites, and molded bodies having any desired antibacterial activity can be easily obtained.

Claims (6)

[Claims] (1) An antibacterial calcium ceramic ceramic selected from calcium phosphate, calcium carbonate, calcium silicate, and hydroxyapatite is loaded with an antibacterial metal selected from silver, copper, and zinc. An antibacterial and antifungal polyolefin resin molded article characterized by being incorporated into. (2) The resin molded article according to claim (1), wherein the calcium-based ceramic is hydroxyapatite. (3) Claim (1) in which the antibacterial metal is silver and/or zinc
) or the resin molded article of (2). (4) The content of antibacterial metal in antibacterial calcium-based ceramics is 0.01% by weight of antibacterial calcium-based ceramics.
10% by weight of the resin molded article according to any one of claims (1) to (3). (5) The resin molded article according to any one of claims (1) to (4), wherein the content of the antibacterial calcium-based ceramic is at least 0.03% by weight based on the molded article. (6) After supporting an antibacterial metal selected from silver, copper, and zinc on a calcium-based ceramic selected from calcium phosphate, calcium carbonate, calcium silicate, and hydroxyapatite, the ceramic is fired at 800°C or higher, A method of producing a polyolefin resin molded article, which comprises pulverizing the fired product to an average particle size of 10 μm or less, and mixing the obtained fine powder with a polyolefin resin so that the content of the fine powder is at least 0.03% by weight. Manufacturing method.