JP2015007199A - Control button for automatic elevator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control button for an automatic elevator having high surface hardness, antibacterial properties and solvent resistance while maintaining transparency and retaining characteristics of a polycarbonate resin such as heat resistance.SOLUTION: A control button for an automatic elevator is formed from a polycarbonate resin comprising: 100 pts.wt. of a resin component comprising 35-75 wt.% of a polycarbonate resin (A) and 25-65 wt.% of a surface hardness improver (B); 0.05-1.5 pts.wt. of a specific antibacterial agent (C) containing an essential component that elutes silver ions; and (D) 0.01-20 pts.wt. of an alkyl ketene dimer having a specific chemical structure. The surface hardness improver (B) is a copolymer comprising 5-80 wt.% of an aromatic (meth)acrylate unit and 20-95 wt.% of a methyl methacrylate unit, where the weight average molecular weight of the copolymer is 5000-30000.

Description

  The present invention relates to a control button for an automatic elevator made of a polycarbonate resin that retains the excellent properties of a polycarbonate resin and, in particular, has excellent surface hardness, hue, antibacterial properties, and solvent resistance.

  Polycarbonate resin is a thermoplastic resin excellent in transparency, impact resistance, heat resistance, thermal stability, and the like, and is widely used in fields such as electricity, electronics, ITE, machinery, and automobiles. However, the polycarbonate resin has a drawback that the surface hardness of a molded product obtained by injection molding / extrusion molding is low and is easily damaged, and its use is limited.

Conventionally, a method of coating the surface of a polycarbonate resin with an ultraviolet curable resin has been proposed to improve the scratch resistance. However, this method is required for display applications because of the flexibility derived from the polycarbonate resin. There is a problem that the pencil hardness requirement cannot be satisfied.
In addition, in order to obtain a molded article having excellent surface hardness and transparency, a resin composition of a polycarbonate resin and an acrylic surface hardness improver has been proposed. This resin composition has a high surface hardness but a hue. There is a problem that (transparency) is inferior, and further improvement is demanded (Patent Document 1 and Patent Document 2).

  On the other hand, in recent years, the need for polycarbonate resin has also diversified, and various chemicals such as hand creams and detergents are used on control buttons for automatic elevators (so-called elevators) such as indoor installation types and outdoor installation types obtained from polycarbonate resins. There is a case where defects such as cracking may occur due to adhesion of a solvent or a solvent, and there is a demand for a control button made of polycarbonate resin having excellent solvent resistance (chemical resistance) so that such problems do not occur. In addition, in this application, there is an increasing demand for antibacterial properties as performance that leads to comfort, cleanliness and safety as well as solvent resistance.

So far, resin compositions in which a polyester resin is blended with a polycarbonate resin have been proposed for the purpose of improving the solvent resistance of the polycarbonate resin. However, in this technology, by adding a polyester resin, the solvent resistance is slightly improved, but cracking or the like occurs in the molded product obtained when an alkaline detergent or machine oil with a strong attack is adhered, Transparency, which is an advantage of polycarbonate resin, may be greatly impaired, and it has been insufficient for solving the problems of this application.
In addition, as a technique for imparting comfort, cleanliness, and safety performance (antibacterial properties) to polycarbonate resin, attempts have been made to blend organic or inorganic antibacterial agents with polycarbonate resin, and among them, Inorganic antibacterial agents are considered promising because they have excellent antibacterial properties and thermal stability.
For example, an antibacterial comprising a zeolite (Patent Document 3) carrying a metal ion such as silver or zinc having a strong antibacterial action against bacteria, or a soluble glass (Patent Document 4 and Patent Document 5) containing the metal ion. Agents.

  In addition, there is also a literature describing a synthetic resin molded body having antibacterial properties including a synthetic resin having a moisture-impermeable structure and a soluble glass that releases silver ions in a highly water-absorbent resin (Patent Document). 6 and Patent Document 7).

  However, even in these technologies, the following problems, that is, the polycarbonate resin may have a molding processing temperature close to 400 ° C. compared to other resins, and the soluble glass and the polycarbonate resin are not formed during the molding processing. There has been a problem that an undesired reaction occurs, resulting in a decrease in transparency (initial coloration) and a decrease in thermal stability of the resulting molded body, and further improvement has been demanded.

JP 2009-280713 A JP 2010-116501 A Japanese Patent No. 3293639 Japanese Patent No. 2135769 Japanese Patent Laid-Open No. 7-25635 Japanese Patent Laid-Open No. 1-313531 Japanese Patent Laid-Open No. 1-153748

  An object of the present invention is to provide a control button for an automatic elevator made of polycarbonate resin that solves the above-mentioned problems, that is, has excellent surface hardness, hue, antibacterial properties, and solvent resistance (chemical resistance).

  As a result of intensive studies to solve the above problems, the present inventors have added a specific surface hardness improver, a specific antibacterial agent, and a specific alkyl ketene dimer in combination to the polycarbonate resin. It was found that a control button for an automatic elevator made of polycarbonate resin excellent in surface hardness, hue (transparency), antibacterial property, and solvent resistance was obtained without impairing various characteristics of the present invention, and the present invention was completed. It was.

The present invention relates to an antibacterial agent containing glass eluting silver ions as an essential component per 100 parts by weight of a resin component comprising 35 to 75% by weight of a polycarbonate resin (A) and 25 to 65% by weight of a surface hardness improver (B) ( C) A polycarbonate resin composition comprising 0.05 to 1.5 parts by weight and 0.01 to 20 parts by weight of an alkyl ketene dimer (D) represented by the following general formula 1, wherein the surface hardness is improved The agent (B) is a copolymer comprising 5 to 80% by weight of aromatic (meth) acrylate units and 20 to 95% by weight of methyl methacrylate units, and the copolymer has a weight average molecular weight of 5,000 to 30,000. A control button for an automatic elevator made of polycarbonate resin is provided.
General formula 1:

（一般式１において、Ｒ１およびＲ２は、同一でも異なっても良いが、炭素数６〜３３のアルキル基をあらわす。）

(In General Formula 1, R1 and R2 may be the same or different, but represent an alkyl group having 6 to 33 carbon atoms.)

  The control button for an automatic elevator made of polycarbonate resin according to the present invention maintains transparency and retains the properties of polycarbonate resin such as heat resistance, while maintaining high surface hardness, antibacterial properties, and solvent resistance (chemical resistance and resistance). Including chemical properties). In addition, the initial coloration of the polycarbonate resin at a molding processing temperature close to 400 ° C. is small, and adverse effects on the hue and deterioration of the buttons due to the outdoor installation of the automatic elevator can be suppressed.

  Hereinafter, the present invention will be described in detail.

  The polycarbonate resin (A) used in the present invention is a phosgene method in which various dihydroxydiaryl compounds and phosgene are reacted or a transesterification method obtained by reacting a dihydroxydiaryl compound and a carbonate such as diphenyl carbonate. A typical example is a polycarbonate resin produced from 2,2-bis (4-hydroxyphenyl) propane (bisphenol A).

  Examples of the dihydroxydiaryl compound include bisphenol 4-, 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 ( Bis (hydroxyaryl) alkanes such as 4-hydroxy-3,5-dichlorophenyl) propane, 1,1- (4-hydroxyphenyl) cyclopentane, bis (hydroxyaryl) cycloalkanes such as 1,1-bis (4-hydroxyphenyl) cyclohexane, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3 Dihydroxy diaryl ethers such as 3,3'-dimethyldiphenyl ether, dihydroxy diaryl sulfides such as 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxy-3,3 ' Dihydroxy diaryl sulfoxides such as dimethyldiphenyl sulfoxide, dihydroxy diary such as 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone Sulfone, and the like.

These can be used alone or in admixture of two or more. In addition to these, piperazine, dipiperidyl hydroquinone, resorcin, 4,4'-dihydroxydiphenyl, and the like may be mixed and used.

  Furthermore, the above dihydroxyaryl compound and a trivalent or higher phenol compound as shown below may be used in combination. Trihydric or higher phenols include 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.

  The viscosity average molecular weight of the polycarbonate resin (A) is usually 10,000 to 100,000, preferably 15,000 to 35,000, and more preferably 17,000 to 28,000. In producing such a polycarbonate resin, a molecular weight regulator, a catalyst and the like can be used as necessary.

  The surface hardness improver (B) used in the present invention is a copolymer composed of 5 to 80% by weight of aromatic (meth) acrylate units and 20 to 95% by weight of methyl methacrylate units. The weight average molecular weight of the coalescence is 5000-30000. In the present specification, (meth) acrylate means acrylate or methacrylate.

  Examples of the aromatic (meth) acrylate include phenyl (meth) acrylate and benzyl (meth) acrylate. These can be used alone or in combination of two or more. Of these, phenyl methacrylate and benzyl methacrylate are preferable, and phenyl methacrylate is more preferable.

  If the content of the aromatic (meth) acrylate unit in the surface hardness improver (B) is 5% by weight or more, transparency is maintained, and if it is 80% by weight or less, the phase with the polycarbonate resin (A) is maintained. Since the capacity is not too high and the transferability to the surface of the molded body is not lowered, the surface hardness is not lowered, which is preferable. Moreover, if the content rate of an aromatic (meth) acrylate unit is the range of 20 to 70 weight%, it is still more preferable from expressing high surface hardness, maintaining transparency further.

  The surface hardness improver (B) may contain other monomer units other than the aromatic (meth) acrylate unit and the methyl methacrylate unit, if necessary. Examples of other monomers constituting other monomer units include methacrylates such as ethyl methacrylate, butyl methacrylate, propyl methacrylate, 2-ethylhexyl methacrylate; methyl acrylate, ethyl acrylate, butyl acrylate, propyl acrylate, 2- Acrylates such as ethylhexyl acrylate and glycidyl acrylate; vinyl cyanide monomers such as acrylonitrile and methacrylonitrile; diene monomers such as butadiene, isoprene and dimethylbutadiene; vinyl ether ethers such as vinyl methyl ether and vinyl ethyl ether Body; carboxylic acid vinyl monomers such as vinyl acetate and vinyl butyrate; olefin monomers such as ethylene, propylene and isobutylene; acrylic acid, methacrylic acid and male Ethylenically unsaturated carboxylic acid monomers such as acid and itaconic acid; vinyl halide monomers such as vinyl chloride and vinylidene chloride; maleimides such as maleimide, N-phenylmaleimide, N-cyclohexylmaleimide and N-methylmaleimide Monomers; Examples include cross-linking agents such as allyl (meth) acrylate, divinylbenzene, and 1,3-butylene dimethacrylate. Of these, methacrylate, acrylate, and vinyl cyanide monomer are preferable, and acrylate is more preferable from the viewpoint of suppressing thermal decomposition of the surface hardness improver (B). These monomers can be used alone or in combination of two or more.

  When other monomer units are contained, the constituent monomers of the surface hardness improver (B) are aromatic (meth) acrylate units of 5-79.9% by weight, methyl methacrylate units of 20-94.9% by weight. And other monomer units in the range of 0.1 to 10% by weight.

  As a polymerization method of the monomer for obtaining the surface hardness improver (B), a known method such as an emulsion polymerization method, a suspension polymerization method, a solution polymerization method, a bulk polymerization method, or the like can be used. A suspension polymerization method and a bulk polymerization method are preferable, and a suspension polymerization method is more preferable. Further, additives necessary for the polymerization can be appropriately added as necessary, and examples thereof include a polymerization initiator, an emulsifier, a dispersant, and a chain transfer agent.

  The weight average molecular weight of the surface hardness improver (B) is 5,000 to 30,000. When the weight average molecular weight is in the range of 5000 to 30000, the compatibility with the polycarbonate resin (A) is good, and the effect of improving the surface hardness is excellent. In addition, Preferably it is the range of 10,000-25000.

The weight average molecular weight is measured using gel permeation chromatography (GPC), and the detailed conditions are as follows:
As a GPC column, PLGEL 5 μm MIXED-C manufactured by Agilent Technologies was used, and THF was used as a mobile phase.

  The ratio of the surface hardness improver (B) used is in the range of 25 to 65% by weight based on the resin component comprising the polycarbonate resin (A) and the surface hardness improver (B). If the proportion of the surface hardness improver (B) used is less than 25% by weight, the effect of improving the surface hardness is lowered, and if it exceeds 65% by weight, the heat resistance and transparency are lowered. More preferably, it is in the range of 35 to 55% by weight.

  The antibacterial agent (C) containing glass that elutes silver ions used in the present invention as an essential component is composed of a glass composition that can elute silver ions. In particular, the composition is preferably a polyhedron including silver oxide, phosphorus oxide, and zinc oxide. When the shape is a polyhedron, since it is easy to orient in a certain direction in the resin, it can be uniformly and easily mixed and dispersed in the resin, and light scattering can be suppressed.

The glass composition of the antibacterial agent (C) is preferably composed of Ag ₂ O in a range of 0.2 to 5% by weight, P ₂ O ₅ in a range of 30 to 80% by weight and ZnO in a range of 30 to 50% by weight. Is done. Further, this _B 2 _{O 3} may be contained a 0.1 to 15 wt% and / or CaO in the range of 0.1 to 15 wt%. In the former case, the silver ions can be stably released, and the transparency of the glass can be improved. In the latter case, a glass excellent in transparency and mechanical strength can be obtained.
When CaO is contained, the weight ratio of CaO to ZnO (ZnO / CaO) is more preferably in the range of 1.1-15.

  Moreover, in order to maintain the transparency of the resin, it is preferable that the average particle size of the glass composition be in the range of 0.1 to 300 μm. The antibacterial glass is readily available as a commercial product, and examples thereof include KM10D manufactured by Sinanen Zeomic.

  The compounding amount of the antibacterial agent (C) is 0.05 to 1.5 per 100 parts by weight of the resin component consisting of 35 to 75% by weight of the polycarbonate resin (A) and 25 to 65% by weight of the surface hardness improver (B). Parts by weight. If the blending amount is less than 0.05 parts by weight, it is difficult to obtain sufficient antibacterial effect. On the other hand, when the amount exceeds 1.5 parts by weight, the transparency is impaired. More preferably, it is the range of 0.1-1.0 weight part.

The alkyl ketene dimer (D) used in the present invention is a compound represented by the following general formula 1.
General formula 1:

  In General Formula 1, R may be the same or different, but is an alkyl group having 6 to 33 carbon atoms, preferably an alkyl group having 10 to 21 carbon atoms.

  In the general formula 1, more preferably, R may be the same or different, but a compound having an alkyl group having 10 to 21 carbon atoms can be used.

  The compounding amount of the alkyl ketene dimer (D) is 0.01 to 20 parts by weight per 100 parts by weight of the resin component consisting of 35 to 75% by weight of the polycarbonate resin (A) and 25 to 65% by weight of the surface hardness improver (B). is there. If it is less than 0.01 parts by weight, the solvent resistance is poor, and if it exceeds 20 parts by weight, it is not preferable because granulation processing becomes difficult and it becomes impossible to obtain pellets of the resin composition. A preferable compounding amount is 0.01 to 10 parts by weight, and more preferably 0.03 to 5 parts by weight.

  Furthermore, various resins, antioxidants, fluorescent brighteners, pigments, dyes, carbon black, fillers, mold release agents, ultraviolet absorbers are added to the polycarbonate resin composition of the present invention within the range not impairing the effects of the present invention. , Antistatic agents, rubber, softeners, spreading agents (liquid paraffin, epoxidized soybean oil, etc.), flame retardants, additives such as organic metal salts, polytetrafluoroethylene resin for preventing dripping, etc. .

  Examples of the various resins include polystyrene, high impact polystyrene, ABS, AES, AAS, AS, acrylic resin, polyamide, polyethylene terephthalate, polybutylene terephthalate, polyarylate, polysulfone, and polyphenylene sulfide resin. Or you may use together by 2 or more types.

  Examples of the antioxidant include phosphorus antioxidants and phenolic antioxidants. Of these, hindered phenolic antioxidants are preferably used. For example, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], thiodiethylene-bis [ Examples include 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate. In particular, a compound represented by the following structural formula is preferably used. Examples of the antioxidant include Irganox 1076 manufactured by Ciba Specialty Chemicals. When a hindered phenol-based oxidizing agent is included, initial coloration during molding of the polycarbonate resin composition can be suppressed.

  As a compounding quantity of a hindered phenolic antioxidant, it is 0.05-1. Per 100 weight part of resin components which consist of polycarbonate resin (A) 35-75 weight% and surface hardness improver (B) 25-65 weight%. 0 weight part is preferable, More preferably, it is the range of 0.1-0.8 weight part.

In order to manufacture the control button for an automatic elevator according to the present invention, the obtained resin composition may be once pelletized and then subjected to molding. As a molding means, any molding method is adopted, for example, by injection molding or the like. Direct molding may be used, or a sheet or film may be once formed by extrusion molding or the like and then molded by vacuum molding or the like. Moreover, it is not necessary to take special conditions as molding conditions. As a manufacturing method for obtaining a button, for example, after the pellets of the obtained polycarbonate resin composition are dried at a predetermined temperature for a predetermined time, the temperature is 250 ° C. to 400 ° C. and the injection pressure is 1500 to 2000 kg using an injection molding machine. There is a method of molding at / cm ² .

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the examples, “parts” and “%” are based on weight unless otherwise specified.

Details of the raw materials used are as follows.
Polycarbonate resin (A):
Polycarbonate resin synthesized from bisphenol A and phosgene (manufactured by Sumika Stylon Polycarbonate, Caliber 200-20, viscosity average molecular weight 19000, hereinafter abbreviated as “PC”)
Surface hardness improver (B):
Copolymer of aromatic (meth) acrylate unit and methyl methacrylate unit (Metbrene H-880 manufactured by Mitsubishi Rayon Co., Ltd., weight average molecular weight 10,000,
Hereinafter abbreviated as “surface hardness improver”)
Antibacterial glass (C):
KM10D manufactured by Sinanen Zeomic (hereinafter abbreviated as “antibacterial agent”)
Alkyl ketene dimer (D):
AKD1840 (hereinafter abbreviated as “AKD”) manufactured by Eiheng Chemical Company
The ingredients are as follows:

上記式でＲは炭素数が１５〜１８のアルキル基である。
酸化防止剤：
チバスペシャリティケミカルズ社製Ｉｒｇａｎｏｘ １０７６（以下「ＡＯ」と略記）

In the above formula, R is an alkyl group having 15 to 18 carbon atoms.
Antioxidant:
Irganox 1076 manufactured by Ciba Specialty Chemicals (hereinafter abbreviated as “AO”)

  In the blending ratios shown in Tables 1 and 2, each of the above raw materials was put into a tumbler and dry mixed for 4 minutes, and then a twin screw extruder (L / D = 42, Φ = 37 mm, KTX-37 manufactured by Kobe Steel) ) Was melt kneaded at a melting temperature of 240 ° C. to obtain pellets of various polycarbonate resin compositions.

(Haze value)
The pellets of the various resin compositions obtained above were each dried at 100 ° C. for 6 hours, and then set at a set temperature of 260 ° C. and an injection pressure of 1600 kg / cm ² using an injection molding machine (Japan Steel Works J-100E-C5). A test piece for transparency evaluation (150 × 90 × 3.0 mm) was prepared.
Using the obtained test piece, the haze value (H) was determined with a haze meter (HM150, manufactured by Murakami Color Research Laboratory Co., Ltd.) in accordance with JIS K7361. The haze value (H) was calculated according to the following formula.
Haze value H (%) = (diffuse transmittance Td / total light transmittance Tt) × 100
A haze value (H) of less than 7.0% was considered good.

(Heat-resistant)
The deflection temperature under load at 23 ° C. was measured according to ISO 75-2. 90 ° C. or higher was considered good.

(Pencil hardness)
The pellets of the various resin compositions obtained above were each dried at 100 ° C. for 6 hours, and then set at a set temperature of 260 ° C. and an injection pressure of 1600 kg / cm ² using an injection molding machine (Japan Steel Works J-100E-C5). A test piece for transparency evaluation (150 × 90 × 2.0 mm) was prepared.
Using the obtained test piece, the pencil hardness at which no scratches were observed on the surface of the test piece was determined with a pencil hardness measuring machine (Pencil scratch coating film hardness tester manufactured by Toyo Seiki Co., Ltd.) according to JISK5600-5-4. . A pencil hardness of HB or higher was considered good.

(Antibacterial)
The antibacterial test was conducted based on JIS Z 2801 (film adhesion method). More specifically, the surface of the initial coloring properties evaluation and similar conditions flat test pieces obtained in (cylinder temperature 270 ° C.), was added dropwise a bacterial suspension containing 10 ⁵ E. coli, PE-made film thereon The cells attached to the PE film and the flat plate test piece after washing at 35 ° C. for 24 hours were washed with an SCDLP medium, transferred to a petri dish, and cultured at 35 ° C. for 45 hours. ) Was counted. The evaluation standard is log ₁₀ (when the number of viable Escherichia coli counted by the film adhesion method using a flat plate test piece made of the resin composition not containing the antibacterial agent (B) of the present invention is x. x / y) (hereinafter abbreviated as antibacterial activity value) was 2.0 or more as good (◯), and less than 2.0 as bad (x).
Further, except for changing Escherichia coli to Staphylococcus aureus, the antibacterial activity test was carried out under the same operation and conditions as described above, the antibacterial activity value was obtained, and evaluated according to the same criteria. The respective results are shown in Tables 1 and 2.

(Evaluation of solvent resistance (chemical resistance) of buttons)
The pellets of the various resin compositions obtained above were each dried at 100 ° C. for 6 hours, and then set at a set temperature of 260 ° C. and an injection pressure of 1600 kg / cm ² using an injection molding machine (Japan Steel Works J-100E-C5). A test piece (127 × 13 × 3.2 mm) was prepared.
The obtained test piece was subjected to an arbitrary strain using a cantilever solvent resistance test jig (see the figure below), and the following solvents were respectively applied to the center of the test piece.
Solvent for evaluation Magiclin manufactured by Kao Corporation
Nivea Kao Nivea Cream (hereinafter abbreviated as Solvent 2)
The test piece after application of the solvent was allowed to stand for 48 hours in an atmosphere of 23 ° C. and 85 ° C., and the critical strain (%) was determined from the position of cracks and cracks on the test piece by the following equation.

(formula)

From the critical strain obtained by the above formula, the solvent resistance was judged according to the following criteria, and the critical strain was determined to be 0.7% or more (◯ to ◎).
Determination of solvent resistance:
◎: Critical strain is 1.0% or more ○: Critical strain is 0.7% or more to less than 1.0% △: Critical strain is 0.5% or more to less than 0.7% ×: Critical strain is 0.3 % Or more to less than 0.5% XX: Critical strain is less than 0.3%

表中「判定」は ○： 良好 、×：不良 を表す。

In the table, “judgment” indicates ○: good, ×: bad.

表中「判定」は ○： 良好 、×：不良 を表す。

In the table, “judgment” indicates ○: good, ×: bad.

As shown in Examples 1 to 6, those satisfying the constituent requirements of the present invention satisfied the required performance.
On the other hand, as shown in Comparative Examples 1 to 6, those not satisfying the constituent requirements of the present invention had the following defects.
In Comparative Example 1, the pencil hardness was poor when the amount of the surface hardness improver was less than the specified amount.
Comparative Example 2 was a case where the blending amount of the surface hardness improver was larger than the prescribed amount, and the heat resistance and haze value were poor.
In Comparative Example 3, the antibacterial property was poor when the blending amount of the antibacterial agent was less than the specified amount.
In Comparative Example 4, the amount of antibacterial agent was greater than the specified amount, and the haze value was poor.
In Comparative Example 5, the chemical resistance was poor when the amount of AKD was less than the specified amount.
In Comparative Example 6, the amount of AKD was larger than the specified amount, and pellets could not be produced due to difficulty in granulation.

Claims (5)

Antibacterial agent (C) having an essential component of glass eluting silver ions per 100 parts by weight of the resin component comprising 35 to 75% by weight of the polycarbonate resin (A) and 25 to 65% by weight of the surface hardness improver (B). A control button for an automatic elevator formed by molding a polycarbonate resin composition characterized by comprising 0.5 to 1.5 parts by weight and 0.01 to 20 parts by weight of an alkyl ketene dimer (D) represented by the following general formula 1. The surface hardness improver (B) is a copolymer comprising 5 to 80% by weight of aromatic (meth) acrylate units and 20 to 95% by weight of methyl methacrylate units, and the weight average molecular weight of the copolymer is A control button for an automatic elevator, which is 5000 to 30000.
General formula 1:

(In General Formula 1, R1 and R2 may be the same or different, but represent an alkyl group having 6 to 33 carbon atoms.)   2. The control button for an automatic elevator according to claim 1, wherein the resin component comprises 45 to 65% by weight of a polycarbonate resin (A) and 35 to 55% by weight of a surface hardness improver (B).   The control button for an automatic elevator according to claim 1, wherein the shape of the glass eluting silver ions contained in the antibacterial agent (C) is a polyhedron.   2. The control button for an automatic elevator according to claim 1, wherein an amount of the antibacterial agent (C) is 0.05 to 1.5 parts by weight per 100 parts by weight of the resin component.   The control button for an automatic elevator according to claim 1, wherein the compounding amount of the alkyl ketene dimer (D) is 0.03 to 5 parts by weight per 100 parts by weight of the resin component.