JPH0477537A - Antibacterial polyolefin composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition having excellent safety and antibacterial property and suitable for kitchen utensils, bathroom furniture, refrigerator, washing machine, etc., by compounding a polyolefin resin with a specific amount of antibacterial hydroxyapatite. CONSTITUTION:The objective composition is produced by compounding 100pts. wt. of a polyolefin resin (preferably PE, PP, etc.) with 0.1-5.0pts.wt. (preferably 0.15-1.0pts.wt.) of an antibacterial hydroxyapatite (preferably containing antibacterial metal such as silver, copper, zinc and tin fixed to hydroxyapatite in ionized state by ion-exchange adsorption).

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a polyolefin composition having antibacterial properties,
In particular, it relates to a polyolefin composition that is safe and has sufficient antibacterial properties, and which does not change color due to the addition of antibacterial agents.

[Prior art and problems to be solved by the invention] Plastics such as polyolefins have generally been considered to be materials with excellent resistance to microorganisms such as fungi (molds) and bacteria. Examples of various types of damage caused by this are listed. In particular, plastic molded bodies used for plumbing products such as kitchen utensils and bath utensils are
Since it is often contaminated with water, it has a tendency to darken due to mold, and it is desired to add antibacterial properties to prevent this. For this reason, plastics that have been treated to prevent mold are now on the market.

Is it generally necessary to add an antibacterial agent to impart antibacterial properties?
Organometallic compounds containing copper, tin, etc. (e.g. 2-(4-
There are organic types such as thiazolyl-benzimidazole (TBB). However, this organic antibacterial agent has problems such as insufficient antibacterial properties, durability, heat resistance, and even safety.

In response to this, recently, zeolite containing a metal having a bactericidal effect has been proposed as an inorganic antibacterial agent (Japanese Patent Application Laid-open No. 241832/1983).

In addition, Japanese Patent Publication No. 63-28402 describes the use of zeolite in which alkaline earth metal carbonates and antibacterial metal ions selected from silver ions, zinc ions, copper ions, or mixtures thereof are adsorbed by ion exchange. Antibacterial compositions suitable for water treatment consisting of molded mixtures have been proposed.

However, such heptaolide-based antibacterial agents have the problem of yellowing of the polyolefin depending on the formulation.

Therefore, an object of the present invention is to provide a polyolefin composition which has sufficient safety and antibacterial properties effective against bacteria and fungi, and which does not change color due to the addition of antibacterial agents.

[Means to solve the problem]

In view of the above issues, as a result of intensive research, the present inventors found that polyolefin resin containing antibacterial hydroxyapatite has sufficient safety and antibacterial properties, and does not discolor due to the combination of antibacterial agents. They found this and came up with the present invention.

That is, the antibacterial polyolefin composition of the present invention is characterized by containing 0.1 to 5.0 parts by weight of antibacterial hydroxyapatite based on 100 parts by weight of the polyolefin resin.

The present invention will be explained in detail below.

In the present invention, the polyolefin includes ethylene,
Homopolymers of α-olefins such as propylene, butene-1, hexene-1,4-methylpentene-1, copolymers of ethylene and propylene or other α-olefins, or two types of these α-olefins. Examples include the above copolymers.

Among these, polyethylene and polypropylene such as low density polyethylene, linear low density polyethylene, medium density polyethylene, and high density polyethylene are preferred. Polypropylene is not limited to a homopolymer, but may include other α-containing materials containing a propylene component of 50 mol% or more, preferably 80 mol% or more.
-Random or block copolymers with olefins can also be used. Comonomers copolymerized with propylene include ethylene and other α-olefins, with ethylene being particularly preferred. Therefore, the term "polypropylene J" used herein is not limited to homopolymers of propylene, but should be understood to include copolymers as well.

In the present invention, antibacterial hydroxyapatite is used as an antibacterial agent blended into polyolefin.

The above-mentioned antibacterial hydroxyapatite is a metal having a bactericidal effect in an ionized state that is exchanged and adsorbed onto hydroxyapatite and fixed therein. From the viewpoint of safety and antibacterial properties, the antibacterial metal is preferably one or more metals selected from the group consisting of silver, copper, zinc, and tin.

In addition, hydroxyapatite, which is suitable as a holding matrix for metals having antibacterial properties, has the following general formula (1): % formula % (11 (where M is an alkali metal such as Ca, Ba, Mg, etc.) P, Si, C, etc.).

As the above-mentioned hydroxyapatite, one represented by the following chemical formula (2): % formula % (21) is particularly preferable.

Since such hydroxyapatite is contained in the polyolefin in the present invention, it is preferable to use powdery particles with as small a particle size as possible, especially particles with an average particle size of 0.5ρ.
The following are suitable for uniform dispersion.

Further, it is preferable that the apatite has a large metal ion exchange capacity.

By using such hydroxyapatite, the amount of one or more of the antibacterial metal ions retained can be arbitrarily adjusted by an ion exchange method to obtain an antibacterial agent having desired antibacterial properties.

The amount of the metal having bactericidal properties is 0.1% by weight to a saturation amount based on 100% by weight of the entire antibacterial hydroxyapatite. Here, the saturated amount is the saturated value of the ion exchange capacity of the hydroxyapatite used. A metal content lower than 0.1% by weight does not provide sufficient antibacterial action. The preferred metal content is 0.1 to 5.0% by weight.

The content of the antibacterial hydroxyapatite as described above is 0.1 to 5.0 parts by weight per 100 parts by weight of polyolefin.
0 parts by weight, preferably 0.15 to 1.0 parts by weight.

If the content of the antibacterial agent is less than 0.1 parts by weight, the antibacterial properties will not be sufficient, and if it exceeds 5.0 parts by weight, not only will the effect not be improved commensurately, but the moldability will deteriorate.

In addition, in the present invention, for the purpose of improving the hue stability, weather resistance, thermal stability, etc. of the antibacterial polyolefin composition, a hindered amine light stabilizer, a neutralizing agent, a phosphorus antioxidant, Phenolic antioxidants and the like may be added.

In addition, in order to add the above-mentioned antibacterial hydroxyapatite, a hindered amide light stabilizer added as necessary, a neutralizing agent, a phosphorus antioxidant, and a phenolic antioxidant to the polyolefin, Any commonly used method may be used.

For example, after premixing polyolefin with antibacterial hydroxyapatite and these additives,
A suitable method is to knead the polyolefin at a temperature higher than the melting point of the polyolefin using an extruder or the like.

The antibacterial polyolefin composition of the present invention may also contain other additives, such as talc,
Inorganic fillers such as mica and wollastonite, heat stabilizers, light stabilizers, flame retardants, plasticizers, antistatic agents, mold release agents, foaming agents, nucleating agents, coloring agents, etc. can be added.

As detailed above, in the present invention, since antibacterial hydroxyapatite is added to polyolefin as an antibacterial agent, the antibacterial polyolefin composition of the present invention has safety and sufficient antibacterial properties. , and will not change color due to the combination of antibacterial agents. Therefore, it has a high commercial value in a wide range of applications.

〔Example〕

Hereinafter, the hue stability and antibacterial properties of antibacterial polyolefin compositions will be shown in Examples.

Examples 1 and 2 Homopolypropylene produced using Ziegler catalyst (melt flow rate (MPI?, 230°C, 2.16k)
(g load) 15 g/10 minutes) 100 parts by weight were mixed with antibacterial hydroxyapatite (Apacider A (trade name), manufactured by Saisangi) in the amount shown in Table 1, and premixed in a 40 A' Henschel mixer. Then, this mixture was put into an extruder (50Mφ, axle screw) at 70 rpm.
The mixture was melted and kneaded under an SN2 blower to form pellets.

Next, the pellets were molded into a size of 80 mm x 80 m at an injection temperature of 240°C using an 8-ounce injection molding machine manufactured by Jujuki ■.
After molding into m×2 test pieces, the hue of this test piece (b
value) was measured using a color meter (digital colorimeter) manufactured by Suga Test Instruments ■. The results are also shown in Table 1.

In addition, this test piece was cut into approximately 1an x 1cm x 2mm, and 10% by weight of this was added to the E. coli suspension, and after shaking in a shake flask for a predetermined period of time, the number of viable bacteria in the solution was measured to check its antibacterial properties. .

The results are shown in Table 1 along with the number of viable bacteria in the E. coli suspension at the start.

Comparative Example 1 A test piece was prepared using only polypropylene without adding antibacterial hydroxyapatite in Example 1.
The hue was measured and antibacterial properties were checked in the same manner as above.

The results are also shown in Table 1.

Example 3 High density polyethylene (melt index Q (1,19
0°C, 2,16kg load) 7g/10min, density 0.9
50g/crl) was mixed with 100 parts by weight of antibacterial nitroxyapatite (Apacider A (trade name), manufactured by Sangi) in the amount shown in Table 1, and premixed with a 40β Henschel mixer. Then, pass this mixture through an extruder (
50mφ, single screw), 70rpm, N2
The mixture was melt-kneaded under blowing to form pellets.

Next, the pellets were molded into 80 mm x 80 m at an injection temperature of 240''C using an 8 oz injection molding machine manufactured by Jujuki ■.
After molding into a m x 2- test piece, the hue of this test piece is
It was measured in the same manner as in Example 1. The results are also shown in Table 1.

Further, this test piece was cut into approximately 1 cm x 1 cm x 2 mm, and the antibacterial properties were checked in the same manner as in Example 1.

The results are shown in Table 1 along with the number of viable bacteria in the E. coli suspension at the start.

Example 4 Antibacterial hydroxyapatite (Avasider A (
(trade name), manufactured by Sangi), pre-mixed using a 40β Henschel mixer, and then melt-kneaded this mixture using an extruder (50-hole diameter, axle screw) at 70 rpm under N2 blowing. and pelletized.

Next, the pellets were molded into 80 mm x 80 mm at an injection temperature of 240°C using an 8 oz injection molding machine manufactured by Jujuki ■.
After molding into a ×2 test piece, the hue of this test piece was measured in the same manner as in Example 1. The results are also shown in Table 1.

In addition, this test piece was cut into approximately 1<em>x 1<em>x 2 mm, and antibacterial properties were checked in the same manner as in Example 1.

The results are shown in Table 1 along with the number of viable bacteria in the E. coli suspension at the start.

As is clear from Table 1, the antibacterial polyolefin composition of the present invention has good antibacterial properties and also maintains low yellowing after injection molding.

〔Effect of the invention〕

Since the antibacterial polyolefin composition of the present invention is made by adding antibacterial hydroxyapatite as an antibacterial agent to polyolefin, it has sufficient safety and antibacterial properties, and does not discolor due to the combination of the antibacterial agent.

The antibacterial polyolefin composition of the present invention having the characteristics mentioned above can be used in fields where mold and other bacteria are likely to grow, such as various kitchen utensils, bath utensils, home appliances such as refrigerators and washing machines, and other plumbing products. suitable.

Applicant: Tonen Petrochemical Co., Ltd.

Claims (4)

[Claims] (1) An antibacterial polyolefin composition containing 0.1 to 5.0 parts by weight of antibacterial hydroxyapatite per 100 parts by weight of the polyolefin resin. (2) The antibacterial polyolefin composition according to claim 1, wherein the antibacterial hydroxyapatite is hydroxyapatite retaining a metal having a bactericidal effect. (3) In the antibacterial polyolefin composition according to claim 2, the metal having a bactericidal effect is one or more metals selected from the group consisting of silver, copper, zinc, and tin, and the hydroxyapatite An antibacterial polyolefin composition characterized in that the metal is exchange-adsorbed in an ionic state and fixed. (4) The antibacterial polyolefin composition according to any one of claims 1 to 3, wherein the hydroxyapatite is represented by Ca_1_0(PO_4)_6(OH)_2.