JP3455331B2 - Method for producing antibacterial polycarbonate resin composition and antibacterial polycarbonate resin composition - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates to an inorganic antibacterial agent and a polycarbonate resin, which have improved thermal stability and heat discoloration resistance, and the antibacterial component does not elute from the resin molded product and the antibacterial effect is maintained for a long time. The present invention relates to an antibacterial polycarbonate resin composition that can be used and a method for producing the same.

[0002]

2. Description of the Related Art Polycarbonate resins having excellent transparency, heat resistance and impact resistance have been used in various fields such as vehicles, light electric appliances and household products. In recent years, various resins have been used. As the antibacterial grade resin composition in which an antibacterial agent is added to the composition has been known, the market demand for the antibacterial polycarbonate resin has increased. As an inorganic antibacterial agent, a metal exhibiting antibacterial properties such as silver and copper is supported on activated carbon, apatite, zeolite, etc., silver, copper, zinc, tin, mercury, lead, iron, cobalt, nickel, manganese, Specific phosphate compounds having metal ions exhibiting antibacterial properties such as arsenic, antimony, bismuth, barium, cadmium and chromium ions (Japanese Patent Application Laid-Open No. 4-42
273803, 3-83906, 3-83905, 6-
305925) and the like, and an antibacterial resin composition comprising them and a resin is also known (JP-A-4-4-2).
75370, 6-212019, 6-263916, 6
-3405414). However, in the case of a resin that requires a relatively high molding temperature such as a polycarbonate resin in practice, when mixed with an antibacterial agent and molded,
Decrease in antibacterial property due to deterioration of antibacterial agent and coloring of resin composition,
There are problems such as accelerated deterioration of polycarbonate resin,
The present situation is that an antibacterial polycarbonate resin composition that retains the original antibacterial properties of the antibacterial agent and retains the original mechanical and optical properties of the polycarbonate resin has not been obtained.

[0003]

The present inventors have developed an antibacterial polycarbonate having the original antibacterial properties of an antibacterial agent to be added without sacrificing the excellent transparency and mechanical strength which are the original characteristics of the polycarbonate resin. In the resin composition,
As a result of earnestly examining the dispersion state of the inorganic antibacterial agent in the polycarbonate resin, the number average dispersed particle diameter in the resin composition of the inorganic antibacterial agent is 0.05 to 5 μ,
By setting the aggregated particles of the inorganic antibacterial agent to less than 1% by weight of the amount of the inorganic antibacterial agent added, the thermal stability and heat discoloration resistance are improved, and the antibacterial component does not elute from the resin molded product and the antibacterial effect is maintained for a long time. The present inventors have found that an antibacterial polycarbonate resin composition that can be sustained can be produced, and arrived at the present invention.

That is, the present invention is a method for producing a resin composition comprising a polycarbonate resin (A) and an inorganic antibacterial agent (B), wherein the number average dispersed particle diameter of the inorganic antibacterial agent in the resin composition is 0. 0.05 to 5 μm, and the aggregated particles of the inorganic antibacterial agent are less than 1% by weight of the amount of the inorganic antibacterial agent added, and a method for producing an antibacterial polycarbonate resin composition, and the method obtained by the method. An antibacterial polycarbonate resin composition is provided. Hereinafter, the present invention will be specifically described.

The polycarbonate resin used in the present invention is known as a phosgene method in which various dihydroxydiaryl compounds are reacted with phosgene, a known transesterification method such as a transesterification method in which a dihydroxydiaryl compound is reacted with a carbonic acid ester such as diphenyl carbonate. A polymer obtained by law, and as a typical one,
A polycarbonate resin produced from 2,2-bis (4-hydroxyphenyl) propane [bisphenol A] can be mentioned.

As the dihydroxydiaryl compound, in addition to bisphenol A, bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl)
Butane, 2,2-bis (4-hydroxyphenyl) octane, bis (4-hydroxyphenyl) phenylmethane, 2,2-bis (4-hydroxyphenyl-3-methylphenyl) propane, 1,1-bis (4 -Hydroxy-3-tert-butylphenyl) propane, 2,2-bis (4-hydroxy-3-bromophenyl) propane,
2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis (4-hydroxy-3,
Bis (hydroxyaryl) alkanes such as 5-dichlorophenyl) propane, bis (hydroxyaryl) such as 1,1-bis (4-hydroxyphenyl) cyclopentane and 1,1-bis (4-hydroxyphenyl) cyclohexane Cycloalkanes, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-
Dihydroxy diaryl ethers such as 3,3′-dimethyldiphenyl ether, 4,4′-dihydroxydiphenyl sulfide, 4,4′-dihydroxy-3,
Dihydroxydiaryl sulfides such as 3'-dimethyldiphenyl sulfide, 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxy-
Examples include dihydroxydiaryl sulfoxides such as 3,3′-dimethyldiphenyl sulfoxide, 4,4′-dihydroxydiphenyl sulfone, and dihydroxydiaryl sulfones such as 4,4′-dihydroxy-3,3′-dimethyldiphenyl sulfone. To be These may be used alone or in admixture of two or more, but in addition to these, piperazine, dipiperidyl hydroquinone, resorcin, 4,4′-dihydroxydiphenyl and the like may be mixed and used.

Further, the above-mentioned dihydroxyaryl compound and a phenol compound having a valence of 3 or more as shown below may be mixed and used. As trihydric or higher phenol, phloroglucin, 4,6-dimethyl-2,4,6-tri-
(4-Hydroxyphenyl) -heptene-2,4,6-
Dimethyl-2,4,6-tri- (4-hydroxyphenyl) -heptane, 1,3,5-tri- (4-hydroxyphenyl) -benzol, 1,1,1-tri- (4-hydroxyphenyl) -Ethane and 2,2-bis-
[4,4- (4,4′-dihydroxydiphenyl) -cyclohexyl] -propane and the like can be mentioned.

The viscosity average molecular weight of the polycarbonate resin is usually 10,000 to 100,000, preferably 15,
It is 000-40,000. In producing such a polycarbonate resin, a molecular weight modifier, a catalyst and the like can be used if necessary.

As the inorganic antibacterial agent used in the present invention,
Antibacterial metals such as silver and copper are activated carbon, apatite,
Having supported on zeolite, etc., it has antibacterial metal ions such as silver, copper, zinc, tin, mercury, lead, iron, cobalt, nickel, manganese, arsenic, antimony, bismuth, barium, cadmium and chromium ions. Known compounds such as phosphate compounds can be used, and one kind or two or more kinds can be used. A phosphate compound containing silver is particularly preferable.

Further, in the present invention, since the number average dispersed particle diameter of the inorganic antibacterial agent in the resin composition is required to be 0.05 to 5 μ, the particle diameter of the inorganic antibacterial agent to be used is 0.
It is required to be 05 to 5 μ.

Further, in the present invention, the aggregated particles of the inorganic antibacterial agent need to be less than 1% by weight of the amount of the inorganic antibacterial agent added. When the agglomerated particles exceed 1% by weight, heat stability, antibacterial properties and total light transmittance are poor, which is not preferable. Here, the term “aggregated particles” as used in the present invention means particles in which two or more unit particles of an inorganic antibacterial agent are aggregated.

The method of mixing the polycarbonate resin (A) and the inorganic antibacterial agent (B) is not particularly limited, and they are mixed by a known mixer such as a tumbler, ribbon blender or high speed mixer, and melt-kneaded by an extruder or the like. You can do it. As described above, in the present invention, it is necessary to make the aggregated particles of the inorganic antibacterial agent less than 1% by weight of the amount of the inorganic antibacterial agent added, but to make the aggregated particles less than 1% by weight, It is desirable to improve the dispersed state of the inorganic antibacterial agent, for example, after premixing the inorganic antibacterial agent and a small amount of polycarbonate resin, a method of melt mixing with a considerable amount of the polycarbonate resin, and the screw of the extruder to be used. It can be prepared by appropriately changing it.

When mixed, known additives such as releasing agents, antistatic agents, antioxidants, ultraviolet absorbers, flame retardants, dyes and pigments (titanium oxide, etc.), and other thermoplastics may be added if necessary. Resins such as polymethylmethacrylate, polybutylene terephthalate, polyethylene terephthalate, and styrene resins can be blended.

The antibacterial polycarbonate resin composition of the present invention can be suitably used for applications requiring antibacterial properties, such as tableware, medical instruments, refrigerators, various packaging materials, brushes, and various water-related products.

The present invention will be specifically described below with reference to examples, but the invention is not limited to these examples. Moreover, "part" is based on a weight basis.

Comparative Example 1 100 parts by weight of a polycarbonate resin (viscosity average molecular weight 22000 consisting of bisphenol A and phosgene) and a commercially available inorganic antibacterial agent Novalon AG-300 (trade name)
1 part by weight of Toa Gosei Co., Ltd. (about 3 μ)) was mixed with a tumbler, and melt-mixed using a 40 mm extruder manufactured by Tanabe Plastic Machinery Co., Ltd. The screw used a full flight type. The temperature settings are as follows.

D C5 C4 C3 C2 C1 250 ° C. 240 ° C. 240 ° C. 240 ° C. 240 ° C. 230 ° C. 230 ° C. The resin pressure is 100 Kg when the rotation speed is 100 rpm.
/ Cm2, the resin temperature was 270 ℃. 4-ounce injection molding machine (K-100 SA2 manufactured by Japan Steel Works, Ltd.)
Injection molded at 310 ° C. with a thickness of 3.2 mm, 5
A 5 mm × 45 mm plate was molded.

Using a scanning electron microscope according to a conventional method, 30
1000 particles were observed on a 00-time electron micrograph to confirm the dispersion state of the inorganic antibacterial agent in the injection plate. The number average dispersed particle diameter of the inorganic antibacterial agent is 3.1.
The ratio of agglomerated particles to the total amount of antibacterial agent added converted from the area of the inorganic antibacterial agent in the electron micrograph was 2.4% by weight.

Comparative Example 2 A polycarbonate resin (made of bisphenol A and phosgene and having a viscosity average molecular weight of 2200) was used without using an inorganic antibacterial agent.
0) An injection plate was prepared in the same manner as in Comparative Example 1 using only the pellets.

Example 1 Using a Henschel mixer, 5 parts by weight of a polycarbonate resin (viscosity average molecular weight 22000 consisting of bisphenol A and phosgene) and 1 part by weight of a commercially available inorganic antibacterial agent Novalon AG-300 (manufactured by Toa Gosei Co., Ltd.) are used. After premixing, pellets 95 of polycarbonate resin (viscosity average molecular weight 22000 consisting of bisphenol A and phosgene)
40m made by Tanabe Plastic Machinery Co., Ltd.
Melt mixing was performed using an m extruder. The screw used was a dullage type. The temperature settings are as follows.

D C5 C4 C3 C2 C1 240 ° C. 230 ° C. 230 ° C. 230 ° C. 220 ° C. 220 ° C. The resin pressure is 110 Kg when the rotation speed is 100 rpm.
/ Cm2, the resin temperature was 260 ℃. An injection plate was prepared in the same manner as in Comparative Example 1.

As a result of examining the dispersion state of the inorganic antibacterial agent by a scanning electron microscope in the same manner as in Comparative Example 1, the number average dispersed particle diameter of the inorganic antibacterial agent was 3.1 μ, and the inorganic antibacterial agent was observed by electron microscope. The ratio of aggregated particles to the total amount of antibacterial agent added calculated from the area of was 0.8% by weight.

Regarding the plates of Comparative Examples 1 and 2 and Example 1, after inoculating the plate surface with Escherichia coli, the plate was stored at 27 ° C. for 3 hours and the number of viable cells was measured. The results are shown in Table 1. Shown in. The result of performing the same operation without using the plate was 1.8.
It was × 10 ⁴ , and this was used as a control.

The results of measuring the yellowness (YI) and the total light transmittance (T%) of the plates of Comparative Examples 1 and 2 and Example 1 are also shown in Table 1.

[0025]

[Table 1]

[0026]

INDUSTRIAL APPLICABILITY In a polycarbonate resin composition containing an inorganic antibacterial agent, the number average dispersed particle diameter of the inorganic antibacterial agent in the resin composition is 0.05 to 5 μm, and the agglomerated particles of the inorganic antibacterial agent are inorganic particles. An antibacterial polycarbonate resin composition in which the thermal stability and the heat discoloration resistance are improved and the antibacterial component is not eluted from the resin molded product and the antibacterial effect can be maintained for a long time by making the amount of the antibacterial agent less than 1% Can be provided.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-6-287355 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08L 69/00

Claims (3)

(57) [Claims] 1. A method for producing a resin composition comprising a polycarbonate resin (A) and an inorganic antibacterial agent (B), wherein the number average dispersed particle diameter of the inorganic antibacterial agent in the resin composition is 0.
The method for producing an antibacterial polycarbonate resin composition is characterized in that the content of the inorganic antibacterial agent is set to be 0 to 5 μm and the aggregated particles of the inorganic antibacterial agent are less than 1% by weight of the amount of the inorganic antibacterial agent added. 2. The method for producing an antibacterial polycarbonate resin composition according to claim 1, wherein the inorganic antibacterial agent (B) is 0.1 to 5 parts by weight per 100 parts by weight of the polycarbonate resin (A). 3. An antibacterial polycarbonate resin composition obtained by the manufacturing method according to claim 1.