JPH06256563A - Antimicrobial thermoplastic resin composition and antimicrobial molding - Google Patents

Abstract

PURPOSE:To obtain a thermoplastic resin composition capable of surely manifesting antimicrobial properties and its resin composition to be a molding material. CONSTITUTION:This thermoplastic resin composition comprises a substance prepared by intercalating quaternary ammonium ions, e.g. benzalkonium ions or cetylpyridinium ions having antimicrobial action as an antimicrobial agent in the spacing between layers of a phosphate forming a sheetlike shape, e.g. aluminum tripolyphosphate in optional thermoplastic resins. Among them, a plyolefinic resin is preferred as the thermoplastic resins. Since the antimicrobial agent has heat resistance stable to the plasticizing temperature of the resins, moldings having high antimicrobial effects and high safety, especially tableware, bathing articles, food packaging films, etc., for business and household uses are obtained.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art A thermoplastic resin composition containing an organic antifungal agent, an antibacterial zeolite or the like in a thermoplastic resin has been disclosed in JP-A-51-1.
It is disclosed in Japanese Patent No. 51740, Japanese Unexamined Patent Publication No. 59-133235, etc., and is a known fact.

However, when it is used in food packaging materials and other fields in which safety equivalent to that is required, such as kitchenware cutting boards, colanders, balls and toothbrushes to be put into the mouth where food comes into direct contact, at least It is desired to meet such conditions.

1) It has no toxicity or irritation and is highly safe, 2) It has a sufficient antibacterial activity against a wide range of bacteria or fungi, and its effect is long-lasting. 3 ) A synthetic resin that withstands the molding temperature and does not cause discoloration or decomposition. 4) A molded product that does not discolor by light.

[0005]

[Problems to be Solved by the Invention] However, in the past,
No thermoplastic resin composition sufficiently satisfies all of the above conditions 1) to 4).

[0006] For example, antibacterial zeolite is highly safe and has a broad antibacterial spectrum, but the minimum inhibitory concentration is relatively large, and it cannot be said that it has sufficient antibacterial activity.
Further, if the concentration is increased, discoloration may occur due to light, which may lower the commercial value.

Although paraoxybenzoic acid esters and propionates, which are recognized as food additives as preservatives, are highly safe, their antibacterial properties are not sufficient at all.

In addition, there are cetylpyridinium chloride, benzalkonium chloride and the like used as throat germicides,
Although these have good antibacterial activity and safety, they cannot be used for those that require molding because they decompose by heat when molding the resin.

Further, the safety of fungicides such as thiazolylbenzimidazole and carbendazine is not sufficient.

[0010]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies in view of such circumstances, and as a result, antibacterial phosphoric acid obtained by intercalating a quaternary ammonium ion having an antibacterial effect on a layered phosphate. A thermoplastic resin composition containing a salt intercalation compound as an antibacterial agent has been found to have no such drawbacks as described above, and has completed the present invention.

That is, the antibacterial thermoplastic resin composition according to the present invention is used as an antibacterial agent (B) in an antibacterial thermoplastic resin composition containing a thermoplastic resin (A) and an antibacterial agent (B). It is characterized by containing an antibacterial phosphate intercalation compound in which a quaternary ammonium ion (D) having an antibacterial action is intercalated in the layered phosphate (C).

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

The thermoplastic resin (A) used in the present invention is not particularly limited, and examples thereof include polyethylene, polypropylene, polystyrene, ABS resin, polyvinyl chloride, polyamide, polyester, polyvinyl alcohol, polycarbonate, polyacetal, and acrylic. Examples thereof include resins, fluororesins, polyurethane elastomers and polyester elastomers, and among them, olefinic thermoplastic resins are preferable.

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 phosphates of trivalent or tetravalent metals such as aluminum phosphate, zirconium phosphate and titanium phosphate may be used alone or in combination.
It is preferable to use a mixture of two or more species. Of these, aluminum triporin phosphate is preferable.

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. %
Is the 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 it is uneconomical.

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

When 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 then pelletized into a master batch pellet with a thermoplastic resin. It is preferable to use it after diluting it because it is excellent in workability.

The masterbatch pellets can be produced, for example, by using an antibacterial agent (B) and a thermoplastic resin such as polyethylene or polypropylene as a carrier resin, and if necessary, polyethylene wax or 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 then pelletized by a pelletizer or the like. When dispersibility is particularly required, it is preferable that the antibacterial agent (B) and a dispersant such as polyethylene wax are kneaded in advance using a kneader such as a heating three-roll roll before use.

A dry color is prepared by mixing an antibacterial agent (B) and a metal soap such as a stearate of a metal such as zinc, aluminum, magnesium or calcium in place of the masterbatch with a Henschel mixer or the like. Good. The antibacterial agent (B) is usually contained in the dry color of 100% by weight in an amount of 5 to 80% by weight.

The masterbatch pellets or dry color thus obtained are mixed with a thermoplastic resin,
When molding such as injection molding, extrusion molding, blow molding, vacuum molding, compression molding, etc., a safe and highly antibacterial molded product is obtained.

The form of the molded product is not particularly limited, but it is a plastic product for household or commercial kitchen, such as a colander, a ball, a cutting board, a drainer, a dish stand, a scissor holder,
Suitable for sinks, washbasins, cups, toothbrushes, etc.

The reaction in which the quaternary ammonium ion intercalates with the layered phosphate in the present invention is considered to be an ion exchange reaction with the proton of the 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 with quaternary ammonium ions by an ion exchange method, such as a general batch method or a column method. It can be performed at room temperature to high temperature depending on the method.

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

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

The quaternary ammonium ion having an antibacterial action in the present invention is a monovalent cation in which four carbon atoms are directly bonded to a nitrogen atom, and examples thereof include an alkyltrimethylammonium ion and a dialkyldimethylammonium ion. Alkyldimethylethylammonium ion, alkyldimethylbenzylammonium ion (benzalkonium ion: alkyl group C ₈ H _{17 to} C ₁₈
H ₃₇ ), alkylpyridinium ion, alkylquinolium ion, alkylamidopropyldimethylbenzylammonium ion, benzyldimethyl p- (1,1,
3,3-tetramethylbutylphenoxy) ethylammonium ion and the like can be mentioned. Among them, benzalkonium ion and cetylpyridinium ion are preferable in terms of antibacterial property.

These are usually supplied by quaternary ammonium salts such as chlorides, bromides and iodides.

These quaternary ammonium ions may be intercalated into the layered phosphate in addition to one kind.

[0029]

EXAMPLES Next, the present invention will be described in detail with reference to examples, but this example is described only for the purpose of illustration and the present invention is not limited to these examples.

Reference Example 1 (Preparation Method of Antibacterial Phosphate Intercalation Compound) Alkylbenzyldimethylammonium ion (alkyl group C ₈ H _{17 to} C ₁₈ H) as quaternary ammonium ion
₃₇ ), and γ-type titanium phosphate was used as the layered phosphate.

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

Next, this solid phase was separated by filtration, water-stopped and dried to obtain an antibacterial phosphate intercalation compound A. Alkylbenzyldimethylammonium ion content is 8.4
%Met.

Reference Example 2 Antibacterial phosphate intercalation compound B was carried out 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 adopted instead of stirring. Got The content of alkylbenzyldimethylammonium ion 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 cetylpyridinium chloride as a quaternary ammonium ion and the mixture was stirred at 80 ° C. for 1 hour. I got C. The content of cetylpyridinium ions was 10.1%.

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

Reference Example 5 As a quaternary ammonium salt, benzalkonium chloride (1
%) And n-butylamine (0.5%) in water 50
10 g of ammonium tripolyphosphate powder was added to 0 ml, and the mixture was stirred for about 2 hours to carry quaternary ammonium ions by ion exchange. Next, the solid phase was filtered and stoppered with water to remove unreacted quaternary ammonium ions, and then dried to obtain antibacterial aluminum phosphate E.
The content of benzalkonium ion was 25.0%.

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

Reference Example 6 Antibacterial aluminum phosphate F in the same manner as in Reference Example 5 except that cetylpyridinium ion was supplied as the quaternary ammonium salt by cetylpyridinium chloride.
Got The content of cetylpyridinium ion is 24.
It was 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 Industry Co., 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 molded into pellets to obtain a master batch having an antibacterial content of 10% by weight.

Next, 2 parts by weight of this masterbatch and J-
After mixing with 109 G [98 parts by weight of polypropylene produced by Ube Industries, Ltd.], a vertical length of 9 was obtained using an injection molding machine at 230 ° C.
A test plate of cm × width 5 cm × thickness 5 mm was prepared.

Examples 2 to 6 and Comparative Examples 1 to 5 Table 1 instead of 1 part by weight of antibacterial phosphate intercalation compound A
Example 1 except that 1 part by weight of each of the antibacterial agents shown in FIG.
Similarly, a masterbatch having an antibacterial agent content of 10% by weight was obtained.

Then, the master batch and the diluted resin were mixed so that the content of the antibacterial agent was the content shown in Table 1, and then 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 test and mold resistance test.

(Antibacterial activity test) 1 ml of a bacterial suspension (10 ⁶ cells / ml) was dropped on a test plate and the mixture was kept at 37 ° C. for 2 hours.
After culturing for 4 hours, wash out the bacterial solution with physiological saline and 10 ml
Diluted to 1 ml of this bacterial solution was dispersed in a Mueller-Hinton medium, and after 24 hours at 37 ° C, the number of surviving individuals was measured.

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

(Mold resistance test) The mold resistance evaluation test is conducted in accordance with 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

Preparation of these 5 kinds of mixed spore suspensions,
0.5 for the sample plate (30 x 30 mm)
After sprinkling in the proportion of ml, temperature 28 ± 2 ℃, humidity 95
The cells were cultured for 4 weeks in a culture tester of ˜99% RH. The test results were evaluated according to the evaluation criteria shown in Table 1.

Table 1 Growth of hyphae Mycelium growth is not observed in the inoculated portion of the sample or test piece showing the fungal resistance 3 . The area of the two growing parts of mycelium observed in the inoculated part of the sample or test piece does not exceed 1/3 of the total area. The area of one growing part of mycelium observed in the inoculated part of the sample or test piece exceeds 1/3 of the total area.

The results of the above-mentioned antibacterial activity test and mold resistance test are summarized in Table 2.

[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 an effect of not causing quality deterioration such as discoloration or deterioration in molding and subsequent use. Further, the antibacterial molded article of the present invention obtained by molding this is highly safe and is useful for sanitary processing of kitchen appliances, toothbrushes and other household plastic products.

Front page continued (72) Yukari Hisatama, Yukari Kutama 1-1-1, Kyobashi, Chuo-ku, Tokyo Lhasa Industrial Co., Ltd. (72) Inventor Hiroei Kawanishi 1-1-1, Kyobashi, Chuo-ku, Tokyo (72) Inventor Takumi Hirosawa 3-9-101 Minamitakahama-cho Suita City, Osaka Prefecture

Claims (6)

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