JP3309869B2 - Antibacterial thermoplastic resin composition and antibacterial molded article - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin composition having antibacterial properties and an antibacterial molded article obtained by molding the same.

[0002]

2. Description of the Related Art It has been disclosed in Japanese Patent Application Laid-Open No. 51-1 to obtain a mold-resistant or antibacterial thermoplastic resin composition by incorporating an organic fungicide or an antibacterial zeolite into a thermoplastic resin.
No. 51740, JP-A-59-133235 and the like are known facts.

[0003] However, when used for food packaging materials and fields requiring the same level of safety as, for example, kitchenware cutting boards, colanders, balls, etc., which come into direct contact with food, and toothbrushes to be put in the mouth, at least the following: It is desired to satisfy various conditions.

[0004] 1) It is highly safe without toxicity or irritation, 2) It has sufficient antibacterial activity against a wide range of bacteria or fungi, and its effect is long lasting. ) The resin must withstand the molding temperature of the synthetic resin and does not cause discoloration or decomposition. 4) The molded article does not discolor by light.

[0005]

However, conventionally,
There was no thermoplastic resin composition that sufficiently satisfies all of the above conditions 1) to 4).

For example, antibacterial zeolites are highly safe and have a broad antibacterial spectrum, but have a relatively low minimum growth inhibitory concentration and cannot be said to have sufficient antibacterial activity.
In addition, when the density is increased, discoloration occurs due to light, which may reduce the commercial value.

[0007] Paraoxybenzoic acid esters and propionates, which are recognized as food preservatives as preservatives, have high safety but are completely insufficient in antibacterial properties.

Other examples include cetylpyridinium chloride and benzalkonium chloride, which are used as throat disinfectants.
Although these have good antibacterial activity and safety, they cannot be used for those requiring molding because they are decomposed by heat during resin molding alone.

Furthermore, fungicides such as thiazolylbenzimidazole and carbendazine are not sufficiently safe.

[0010]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in view of such circumstances, and as a result, have found that an antibacterial phosphate in which a quaternary ammonium ion having an antibacterial action has been intercalated into a layered phosphate. The present inventors have found that a thermoplastic resin composition containing a salt intercalation compound as an antibacterial agent does not have the above-mentioned disadvantages, and have completed the present invention.

That is, the antibacterial thermoplastic resin composition according to the present invention is an antibacterial thermoplastic resin composition containing a thermoplastic resin (A) and an antibacterial agent (B), which is used as the antibacterial agent (B). The layered phosphate (C) contains an antibacterial phosphate interlayer compound obtained by intercalating a quaternary ammonium ion (D) having an antibacterial action.

Further, the antibacterial thermoplastic resin molded product according to the present invention is characterized in that the antibacterial thermoplastic resin composition is formed into a desired shape.

The thermoplastic resin (A) used in the present invention is not particularly limited. For example, polyethylene, polypropylene, polystyrene, ABS resin, polyvinyl chloride, polyamide, polyester, polyvinyl alcohol, polycarbonate, polyacetal, acrylic Resins, fluororesins, polyurethane elastomers, polyester elastomers and the like can be mentioned, among which olefin-based thermoplastic resins are preferred.

The antibacterial phosphate intercalation compound used as the antibacterial agent (B) in the present invention is characterized in that a quaternary ammonium ion having an antibacterial action is intercalated into a layered phosphate.

The layered phosphate is not particularly limited, but a phosphate of a trivalent or tetravalent metal such as aluminum phosphate, zirconium phosphate and titanium phosphate may be used alone or in the form of a phosphate.
It is preferred to use a mixture of more than one species. Among them, aluminum triporin phosphate is preferred.

The content of the antibacterial agent (B) in the thermoplastic resin composition and the molded product is not particularly limited, but is usually 0.1 to 20% by weight, preferably 0.3 to 5% by weight. %
Range. If the content is less than 0.1% by weight, the antibacterial effect is insufficient, and if it exceeds 20% by weight, the effect is practically unchanged and uneconomical.

The thermoplastic resin composition of the present invention may further contain, if necessary, various additives such as an antioxidant, an inorganic filler, a fatty acid ester wax, a polyethylene wax, an antistatic agent, and an ultraviolet absorber. , An organic pigment, an inorganic pigment and the like may be added.

At the time of molding the thermoplastic resin composition of the present invention, a thermoplastic resin composition containing 1 to 50% by weight of an antibacterial agent is melt-kneaded, and the pelletized masterbatch pellet is mixed with the thermoplastic resin. It is preferable to use it after diluting it because it is excellent in workability.

The method for producing the master batch pellets includes, for example, an antimicrobial agent (B) and a carrier resin such as a thermoplastic resin such as polyethylene or polypropylene, and, if necessary, a polyethylene wax or a fatty acid ester wax.
After mixing a dispersant such as metal soap, the mixture is melt-kneaded at a temperature equal to or higher than the softening point of the carrier resin, and further shaped into pellets by a pelletizer or the like. When dispersibility is particularly required, it is preferred that the antibacterial agent (B) and a dispersant such as polyethylene wax are kneaded in advance using a kneading machine such as a three-roll roll before use.

Alternatively, a dry color is prepared by mixing the antibacterial agent (B) and a metal soap such as a stearate of a metal such as zinc, aluminum, magnesium, or calcium with a Hensiel mixer or the like instead of the masterbatch. Is also good. The antibacterial agent (B) is usually contained in 5 to 80% by weight in 100% by weight of the dry color.

The masterbatch pellet or dry color thus obtained is mixed with a thermoplastic resin,
By performing molding such as injection molding, extrusion molding, blow molding, vacuum molding, compression molding, etc., a safe and highly antibacterial molded product can be obtained.

Although there is no particular limitation on the form of the molded product, plastic products for kitchens for home or business use, such as colander, balls, cutting boards, drainers, dish stands, scoops,
Also suitable for use in sinks, sinks, cups, toothbrushes, etc.

The reaction of the present invention in which a quaternary ammonium ion is intercalated into a layered phosphate is considered to be an ion exchange reaction with a proton of a hydrogen phosphate group. In the production of the antibacterial phosphate intercalation compound of the present invention, a part or all of the ion-exchangeable protons may be replaced by quaternary ammonium ions by an ion exchange method, and a general batch method or a column method may be used. Depending on the method, it can be performed at room temperature to high temperature.

Further, when part or all of the ion-exchangeable protons are used after being previously substituted with an alkali metal ion such as Na ion or an alkylammonium ion such as n-butylammonium ion,
In some cases, ion exchange with quaternary ammonium ions can be performed more efficiently.

As described above, after the quaternary ammonium ions are intercalated into the layered phosphate by ion exchange, the solid phase is separated by filtration, washed with water to remove unreacted quaternary ammonium ions, and then dried. By doing so, a layered phosphate in which quaternary ammonium ions are intercalated, that is, the antibacterial phosphate intercalation compound of the present invention is obtained.

The quaternary ammonium ion having an antibacterial action according to the present invention is a monovalent cation in which four carbon atoms are directly bonded to a nitrogen atom, such as an alkyltrimethylammonium ion, a dialkyldimethylammonium ion, alkyl dimethyl ethyl ammonium ions, alkyl dimethyl benzyl ammonium ion (benzalkonium ion: alkyl C ₈ H ₁₇ ~C ₁₈
H ₃₇ ), alkylpyridinium ion, alkylquinolium ion, alkylamidopropyldimethylbenzylammonium ion, benzyldimethyl p- (1,1,
3,3-tetramethylbutylphenoxy) ethylammonium ion and the like. Of these, benzalkonium ion and cetylpyridinium ion are preferable in terms of antibacterial properties.

These are usually supplied by quaternary ammonium salts such as chloride, bromide and iodide.

Not only one kind of these quaternary ammonium ions but also several kinds thereof may be intercalated into the layered phosphate.

[0029]

EXAMPLES Next, the present invention will be described in detail with reference to examples. However, the present examples are described merely for the purpose of illustration, and the present invention is not limited to these examples.

Reference Example 1 (Preparation of antibacterial phosphate intercalation compound) Alkylbenzyldimethylammonium ion (alkyl group C ₈ H _{17 to} C ₁₈ H) as a quaternary ammonium ion
₃₇ ), γ-type titanium phosphate was used as a layered phosphate.

10 g of γ-type titanium phosphate was placed in 500 ml of a 1% aqueous solution of alkylbenzyldimethylammonium chloride (benzalkonium chloride) and stirred at room temperature for about 5 hours to perform intercalation.

Next, the solid phase was separated by filtration, dried with a water faucet, and dried to obtain an antibacterial phosphate interlayer compound A. The content of alkylbenzyldimethylammonium ion is 8.4
%Met.

Reference Example 2 An antibacterial phosphate intercalation compound B was prepared in the same manner as in Reference Example 1 except that α-type zirconium phosphate was used as the layered phosphate and ultrasonic dispersion was used instead of stirring. I got The content of alkylbenzyldimethylammonium ions was 9.3%.

Reference Example 3 An antibacterial phosphate intercalation compound was prepared in the same manner as in Reference Example 1 except that cetylpyridinium ion was supplied as quaternary ammonium ion by cetylpyridinium chloride, and stirring was performed at 80 ° C. for 1 hour. C was obtained. The content of cetylpyridinium ion was 10.1%.

Reference Example 4 An antibacterial phosphate interlayer compound D was obtained in the same manner as in Reference Example 1 except that cetyltrimethylammonium ion was supplied as quaternary ammonium ion using cetyltrimethylammonium bromide. The content of cetyltrimethylammonium ion was 8.2%.

Reference Example 5 Benzalkonium chloride (1) was used as a quaternary ammonium salt.
%) And n-butylamine (0.5%) aqueous solution 50
10 g of ammonium tripolyphosphate powder was added to 0 ml and stirred for about 2 hours to carry quaternary ammonium ions by ion exchange. Next, the solid phase was filtered and water-flushed to remove unreacted quaternary ammonium ions, followed by drying to obtain antibacterial aluminum phosphate E.
The content of benzalkonium ions was 25.0%.

Here, n-butylamine was used as a catalyst for supporting quaternary ammonium ions on aluminum phosphate.

Reference Example 6 An antibacterial aluminum phosphate F was prepared in the same manner as in Reference Example 5 except that cetylpyridinium ions were supplied as quaternary ammonium salts by cetylpyridinium chloride.
I got The content of cetylpyridinium ion is 24.
5%.

Example 1 1 part by weight of antibacterial phosphate intercalation compound A, 1 part by weight of sun wax 161p [polyethylene wax manufactured by Sanyo Chemical Industries, Ltd.] and F-171 [low-density polyethylene manufactured by Showa Denko KK] After mixing 8 parts by weight with a Henschel mixer, the mixture was melt-kneaded using an extruder at a temperature of 170 ° C., and then formed into pellets to obtain a master batch having an antibacterial content of 10% by weight.

Next, 2 parts by weight of this master batch and J-
After mixing with 98 parts by weight of 109G (polypropylene manufactured by Ube Industries, Ltd.), the mixture was mixed in a vertical direction using a 230 ° C. injection molding machine.
A test plate of cm × 5 cm × 5 mm thick was prepared.

Examples 2-6 and Comparative Examples 1-5 Antibacterial phosphate intercalation compound A
Example 1 except that 1 part by weight of the antibacterial agent shown in
Similarly, a master batch having an antibacterial agent content of 10% by weight was obtained.

Next, this master batch and the diluting resin were mixed so that the content of the antibacterial agent became the content shown in Table 1, and a test plate was prepared in the same manner as in Example 1.

Test Examples The test plates prepared in Examples 1 to 6 and Comparative Examples 1 to 5 were subjected to the following antibacterial activity tests and mold resistance tests.

(Antibacterial activity test) 1 ml of a bacterial suspension (10 ⁶ cells / ml) was dropped on a test plate,
After culturing for 4 hours, the bacterial solution is washed out with physiological saline, and 10 ml
It was diluted to become. 1 ml of this bacterial solution was dispersed in a Mueller-Hinton medium, and the number of surviving individuals was measured after 24 hours at 37 ° C.

The following bacteria were used as test bacteria. Escherichia coli Staphylococcus aureus Pseudomonas aeruginosa

(Mold Resistance Test) The mold resistance evaluation test is performed according to Japanese Industrial Standards “Mold resistance test method” JIS Z-
2911. The following five types were used as test bacteria. Aspergillus niger (Penicillium citrinum) Rhizopus stolonifer (Cladospori)
um cladosporioides) Chaetomium globosum

These five types of mixed spore suspensions were prepared,
This is applied to a sample plate (30 × 30 mm) by 0.5
After spraying at a rate of 28 ml, temperature 28 ± 2 ° C, humidity 95
The cells were cultured for 4 weeks in a culture tester of ９９99% RH. The test results were evaluated according to the evaluation criteria shown in Table 1.

The hyphae growth is not 3 observed in the inoculated portion of Table 1 bacteria yarn originating education fungus resistance of the display sample or specimen. The area of the two growing mycelia in the inoculated portion of the sample or test piece does not exceed 1/3 of the total area. The area of one growing mycelium in the inoculated portion of the sample or test piece is more than 1/3 of the total area.

Table 2 summarizes the results of the above antibacterial activity test and mold resistance test.

[0050]

[0051]

The antibacterial thermoplastic resin composition of the present invention comprises:
It has a broad antibacterial spectrum, has a strong antibacterial activity, and has the effect of preventing deterioration in quality such as discoloration or deterioration in molding and subsequent use. Further, the antibacterial molded product of the present invention obtained by molding it has high safety and is useful for sanitary processing of kitchenware, toothbrushes and other household plastic products.

Continuation of the front page (72) Inventor Yukari Kudama 1-1-1, Kyobashi, Chuo-ku, Tokyo Lhasa Industrial Co., Ltd. (72) Inventor Hiroei Kawanishi 1-1-1, Kyobashi, Chuo-ku, Tokyo Lhasa Industrial Stock In-company (72) Inventor Takumi Hirosawa 3-9-101 Minamitakahama-cho, Suita-shi, Osaka (56) References JP-A-4-275370 (JP, A) JP-A-4-243908 (JP, A) Kaihei 5-124806 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 1/00-101/16 C08K 3/00-13/08 A01N 59/26

Claims (6)

(57) [Claims] 1. An antibacterial thermoplastic resin composition comprising a thermoplastic resin (A) and an antibacterial agent (B), having an antibacterial effect on the layered phosphate (C) as the antibacterial agent (B). An antibacterial thermoplastic resin composition containing an antibacterial phosphate intercalation compound obtained by intercalating a quaternary ammonium ion (D). 2. The composition according to claim 1, wherein the layered phosphate (C) in the antibacterial agent (B) is aluminum tripolyphosphate. 3. The composition according to claim 1, wherein in the antibacterial agent (B), the quaternary ammonium ion (D) is a benzalkonium ion and / or a cetylpyridinium ion. 4. An antibacterial thermoplastic resin molded product containing a thermoplastic resin (A) and an antibacterial agent (B), has an antibacterial effect on the layered phosphate (C) as the antibacterial agent (B). An antibacterial thermoplastic resin molded article comprising an antibacterial phosphate intercalation compound obtained by intercalating a quaternary ammonium ion (D). 5. The molded article according to claim 4, wherein the layered phosphate (C) in the antibacterial agent (B) is aluminum tripolyphosphate. 6. The molded article according to claim 4, wherein in the antibacterial agent (B), the quaternary ammonium ion (D) is a benzalkonium ion and / or a cetylpyridinium ion.