JP2012126779A - Housing for game machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a housing for a game machine made of a polycarbonate resin composition which overcomes the fault like the decrease in jet blackness and the whitening when a carbon black and a silicone oil are used, has the excellent jet blackness (piano black-like appearance) that have not been achieved in the prior art, and has excellent flame retardancy.SOLUTION: The housing for a game machine comprises forming a polycarbonate resin composition which includes: 100 pts.wt. of a polycarbonate resin (A); 0.05-1.0 pts.wt. of an organic based black dye (B) having a specific optical characteristic; 0.01-5.0 pts.wt. of a silicone compound (C) in which a main chain is a branch structure and a contained organic functional group consists of an aromatic group or consists of an aromatic group and a hydrocarbon group (excluding aromatic group); 0.01-2.0 pts.wt. of an organic metal salt compound (D); and 0.05-2.0 pts.wt. of a fiber formation type fluorine-containing polymer (E).

Description

  The present invention relates to a housing for a game machine made of polycarbonate resin that is excellent not only in flame retardancy but also in jetness. More specifically, the present invention relates to a gaming machine housing having excellent flame retardancy and jet blackness while maintaining the impact resistance, heat resistance, thermal stability, etc., which are the characteristics of polycarbonate resin. The game machine housing of the present invention has a beautiful, heavy, and high-quality appearance.

  Polycarbonate resin is a thermoplastic resin excellent in impact resistance, heat resistance, thermal stability, and the like, and is widely used in fields such as electricity, electronics, ITE, machinery, and automobiles. On the other hand, in applications for game consoles, while taking advantage of these excellent performances of the resin, it has excellent jetness from the viewpoint of design and design of the obtained molded product (also called piano black) Appearance is desired, and flame retardancy is also required.

  As a technique for imparting jet blackness to a polycarbonate resin composition, a technique for adding carbon black having high concealment (Patent Document 1), a technique for adding silicone oil (Patent Document 2), and the like have been proposed. However, when a carbon black pigment is added, it is difficult to develop high jetness although the concealability is improved. On the other hand, the addition of silicone oil has a problem of whitening during molding.

  Polycarbonate resin, on the other hand, is a highly flame-retardant plastic material with excellent impact resistance, heat resistance, thermal stability, etc., and self-extinguishing properties, but it retains high jet black and is underwriters laboratories. There is a demand for a housing for a game machine having higher flame resistance equivalent to V-0 in the evaluation of flame retardancy in accordance with UL94 test (flammability test of plastic materials for equipment parts) defined by .

  As a technique for imparting flame retardancy to a polycarbonate resin, conventionally, a method of blending chlorine, a bromine compound, or a phosphorus compound as a flame retardant has been adopted. However, chlorine and bromine-based flame retardants exhibit excellent flame retardant effects, but have problems such as corrosion of molding machine screws and product molds during injection molding. Moreover, although the phosphorus-based flame retardant is mainly used as a condensed phosphate ester-based flame retardant, there is a problem that an extreme decrease in heat resistance or impact strength occurs. In view of these remarkable physical properties and environmental considerations, it is desired to use a flame retardant that does not contain halogen compounds such as bromine and chlorine and phosphorus compounds.

  As a method of making flame retardant without using the above flame retardant, a method of adding an aromatic sulfonic acid metal salt (Patent Document 3), a method of adding potassium perfluoroalkane sulfonate (Patent Document 4), an organic alkali metal salt A method of adding an organic alkaline earth metal salt and a fluorinated polyolefin (Patent Document 5) and a method of adding a silicone resin (Patent Document 6) have been proposed. By using these methods, in the evaluation of flame retardancy based on the UL94 test, although the effect of reducing combustion time and the effect of suppressing dripping of resin during combustion are recognized to some extent, even more excellent flame retardancy There is a demand for the development of a material having properties.

JP 2003-96286 A JP 2004-210889 A JP 50-98546 A Japanese Patent Publication No. 47-40445 JP 51-45159 Japanese Patent Laid-Open No. 10-139964

  The object of the present invention is to overcome the above-mentioned problems in the prior art, that is, to overcome the drawbacks of jet black deterioration and whitening when carbon black or silicone oil is used, and to achieve excellent jet blackness that could not be achieved by the prior art. Another object of the present invention is to provide a housing for a gaming machine made of polycarbonate resin that has (has a piano black-like appearance) and also has excellent flame retardancy.

  As a result of intensive studies in view of such an object, the present inventors have improved the jetness of the obtained molded product by blending an organic black dye having specific optical performance with a polycarbonate resin having transparency. The present inventors have found that a piano black-like appearance can be obtained, and that the above-mentioned problems can be solved by using a specific flame retardant and a flame retardant aid together, thereby completing the present invention.

That is, the present invention is a game machine housing formed by molding a polycarbonate resin composition,
(1) The polycarbonate resin composition has 100 parts by weight of the polycarbonate resin (A), 0.05 to 1.0 parts by weight of the organic black dye (B), the main chain has a branched structure, and the organic functional group contained is aromatic. 0.01 to 5.0 parts by weight of a silicone compound (C) comprising an aromatic group or an aromatic group and a hydrocarbon group (excluding an aromatic group), 0.01 to 5.0 organometallic salt compound (D) A polycarbonate resin composition containing 2.0 parts by weight and 0.05 to 2.0 parts by weight of a fiber-forming fluoropolymer (E) as essential components;
(2) The optical characteristics of the organic black dye (B) were obtained by injection molding a resin composition comprising 100 parts by weight of the polycarbonate resin (A) and 0.3 parts by weight of the organic black dye (B). Thickness 1 obtained by measuring the light transmittance of a flat plate having a thickness of 2 mm and having a light transmittance of 50% or more in a wavelength range of 800 to 900 nm, and (3) molding the polycarbonate resin composition. When a combustion test is performed based on a UL94 test method (flammability test of plastic material for equipment parts) using a 5 mm test piece, it has a V-0 rating.
A game machine housing is provided.

  The housing for a game machine of the present invention has a beautiful, heavy and high-quality piano black-like appearance while maintaining the excellent impact strength, heat resistance, thermal stability, etc. inherent in polycarbonate resin, and is difficult. Excellent flammability.

  The polycarbonate resin (A) used in the present invention is obtained by a phosgene method in which various dihydroxydiaryl compounds and phosgene are reacted, or a transesterification method in which a dihydroxydiaryl compound and a carbonate such as diphenyl carbonate are reacted. A typical example of the polymer is a polycarbonate resin produced from 2,2-bis (4-hydroxyphenyl) propane (commonly referred to as 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 may be used alone or in combination of two or more. In addition to these, piperazine, dipiperidyl hydroquinone, resorcin, 4,4′-dihydroxydiphenyl, and the like may be used in combination.

  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 not particularly limited, but is usually in the range of 10,000 to 100,000, more preferably 14,000 to 30,000, and even more preferably 16,000 to 26,000 in terms of moldability and strength. Moreover, when manufacturing this polycarbonate resin (A), a molecular weight regulator, a catalyst, etc. can be used as needed.

The above viscosity average molecular weight is 0.5 wt% polycarbonate resin solution using methylene chloride as a solvent, and the specific viscosity (η _sp ) is measured at a temperature of 20 ° C. using a Cannon-Fenske type viscosity tube. [Η] was obtained and calculated from the following SCHNELL equation.
[Η] = 1.23 × 10 ⁻⁴ M ^0.83

  Examples of the organic black dye (B) used in the present invention include a mixture of organic dyes such as anthraquinone, perinone, perylene, azo, methine, and xylinone. In particular, anthraquinone-based and perinone-based organic dyes are preferably used. Anthraquinone-based organic dyes such as blue, purple and green are preferable, and perinone-based organic dyes such as red and orange are preferable.

  The organic black dye (B) of the present invention is obtained by injection molding a resin composition comprising 100 parts by weight of a polycarbonate resin (A) and 0.3 part by weight of an organic black dye (B) as its optical characteristics. When measuring the light transmittance of a flat plate having a thickness of 2 mm, it is necessary to have a light transmittance of 80% or more in a wavelength region of 800 to 900 nm. The light transmittance is measured according to ASTM D-1003.

  When the light transmittance is less than 50%, an excellent jet black (piano black-like) appearance cannot be obtained, which is not preferable. The light transmittance is preferably 60% or more, more preferably 80% or more.

  Moreover, as a compounding quantity of organic type black dye (B), it is 0.05-1.0 weight part with respect to 100 weight part of polycarbonate resin (A). If the blending amount is less than 0.05 parts by weight, the jet blackness and the hiding property are inferior, and if it exceeds 1.0 parts by weight, the thermal stability of the polycarbonate resin (A) is inferior, and further, the amount of gas generated during molding is large. This is not preferable. A more preferable blending amount is in the range of 0.1 to 0.5 parts by weight, and more preferably 0.2 to 0.3 parts by weight.

The silicone compound (C) used in the present invention comprises a branched main chain and an organic functional group comprising an aromatic group, or an aromatic group and a hydrocarbon group (excluding an aromatic group). Is represented by the following general formula (1).
General formula (1)

Here, R1, R2, and R3 represent main chain organic functional groups, and X represents a terminal functional group.
That is, it has a T unit (RSiO _1.5 ) and / or a Q unit (SiO _2.0 ) as a branch unit. These preferably contains more than 20 mol% of the total siloxane units _{(R 3~0 SiO 2~0.5).} (R represents an organic functional group.) Further, the silicone compound (C) preferably contains 20 mol% or more of aromatic groups among the organic functional groups contained.

  The aromatic group contained is phenyl, biphenyl, naphthalene or a derivative thereof, but a phenyl group can be preferably used.

  Of the organic functional groups in the silicone compound (C) attached to the main chain or branched side chain, the organic group other than the aromatic group is preferably a hydrocarbon group having 4 or less carbon atoms, and preferably a methyl group. Can be used. Further, the terminal group is preferably one kind selected from methyl group, phenyl group and hydroxyl group, or a mixture of these two kinds to three kinds.

  The average molecular weight (weight average) of the silicone compound (C) is preferably 3,000 to 500,000, and more preferably 5,000 to 270000.

  The compounding quantity of a silicone compound (C) is 0.01-5.0 weight part with respect to 100 weight part of polycarbonate resin (A). When the blending amount is less than 0.01 parts by weight, the flame retardancy is inferior, and when the blending amount exceeds 5.0 parts by weight, surface layer peeling occurs on the surface of the molded product and the appearance is inferior. Preferably it is 0.05-2.0 weight part, More preferably, it is the range of 0.05-1.0 weight part.

  Examples of the organic metal salt compound (D) used in the present invention include aromatic sulfonic acid metal salts and perfluoroalkanesulfonic acid metal salts. Examples of the metal include alkali metals and alkaline earth metals. Preferably, potassium salt of 4-methyl-N- (4-methylphenyl) sulfonyl-benzenesulfonamide, potassium diphenylsulfone-3-sulfonate, potassium diphenylsulfone-3-3｀-disulfonate, paratoluenesulfonic acid Sodium, perfluorobutanesulfonic acid potassium salt, etc. can be used.

  The compounding quantity of an organometallic salt compound (D) is 0.01-2.0 weight part with respect to 100 weight part of polycarbonate resin (A). If the blending amount is less than 0.01 parts by weight, the flame retardancy is lowered, which is not preferable. On the other hand, if the amount exceeds 2.0 parts by weight, problems such as reduction in flame retardancy and mechanical strength are not preferable. Preferably it is 0.02-1.0 weight part, More preferably, it is 0.02-0.8 weight part.

  As the fiber-forming fluorine-containing polymer (E) used in the present invention, those that form a fiber structure (fibril structure) in the polycarbonate resin (A) are preferable. Polytetrafluoroethylene, tetrafluoroethylene Examples thereof include a system copolymer (for example, tetrafluoroethylene / hexafluoropropylene copolymer, etc.), a partially fluorinated polymer as shown in US Pat. No. 4,379,910, a polycarbonate produced from a fluorinated diphenol, and the like. In particular, polytetrafluoroethylene having a molecular weight of 1,000,000 or more and a fibril-forming ability having a secondary particle diameter of 100 μm or more is preferably used.

  The compounding amount of the fiber-forming fluoropolymer (E) is 0.05 to 2.0 parts by weight with respect to 100 parts by weight of the polycarbonate resin (A). If the blending amount is less than 0.05 parts by weight, the effect of preventing dripping during combustion is inferior, which is not preferable. On the other hand, if the amount exceeds 2.0 parts by weight, granulation becomes difficult, which hinders stable production. The amount is preferably 0.05 to 1.0 part by weight, more preferably 0.1 to 0.5 part by weight. In this range, the balance between flame retardancy and moldability is further improved.

  There are no particular limitations on the method of blending the various blending components (A), (B), (C), (D), and (E) of the present invention, and any mixer, such as a tumbler, ribbon blender, high-speed mixer, etc. These can be mixed and easily melt-kneaded with a normal single-screw or twin-screw extruder. Moreover, there is no restriction | limiting in particular also about these compounding orders.

  In addition, other known additives such as mold release agents, ultraviolet absorbers, fillers, antistatic agents, antioxidants, phosphorous heat stabilizers, dyes and pigments, spreading agents (epoxies) may be used as necessary. Soybean oil, liquid paraffin, etc.) can be blended. Examples of the filler include glass fiber, glass bead, glass flake, carbon fiber, talc powder, clay powder, mica, potassium titanate whisker, aluminum borate whisker, wollastonite powder, silica powder and the like. Examples of mica include muscovite, biotite, phlogopite, and artificial phlogopite, and those having a flake shape are suitable.

  As a manufacturing method of the game machine housing of the present invention, methods such as injection molding, injection compression molding, and injection press molding can be employed.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Unless otherwise noted, based on weight standards.

The details of the used blending components are as follows.
Polycarbonate resin:
Polycarbonate resin synthesized from bisphenol A and phosgene (Sumitomo Dow Caliber 200-20 (viscosity average molecular weight: 19000)
(Hereinafter abbreviated as PC)

Organic black dye:
Sumiplast Black HB
(Manufactured by Sumika Chemtex Co., Ltd., hereinafter abbreviated as Colorant 1)
Light transmittance in a wavelength range of 800 to 900 nm: 85%
Sumiplast Black HLG
(Manufactured by Sumika Chemtex Co., Ltd., hereinafter abbreviated as Colorant 2)
Light transmittance in the wavelength region of 800 to 900 nm: 55%
Carbon black:
Furnace type carbon black (XC-305 manufactured by Cabot Corporation, hereinafter abbreviated as Colorant 3)
Light transmittance in a wavelength range of 800 to 900 nm: less than 1%

Silicone compound: (hereinafter abbreviated as silicone compound)
The silicone compound was produced according to a general production method. That is, a silicone compound partially condensed by dissolving an appropriate amount of diorganodichlorosilane, monoorganotrichlorosilane and tetrachlorosilane, or a partially hydrolyzed condensate thereof in an organic solvent, adding water and hydrolyzing it. Then, triorganochlorosilane was added and reacted to terminate the polymerization, and then the solvent was separated by distillation or the like. The structural characteristics of the silicone compound synthesized by the above method are as follows:
・ D / T / Q unit ratio of main chain structure: 40/60/0 (molar ratio)
-Ratio of phenyl group in all organic functional groups (*): 60 mol%
-Terminal group: methyl group only-Weight average molecular weight (**): 15000
*: The phenyl group is first contained in the T unit in the silicone containing the T unit, and the remaining D group is contained in the D unit. When the phenyl group is attached to the D unit, the one attached is preferential, and when the phenyl group remains, two are attached. Except for the terminal group, the organic functional group is a methyl group except for the phenyl group.
**: Weight average molecular weight is two significant digits.

Organometallic salt compound Perfluorobutanesulfonic acid potassium salt (Bayowet C-4 manufactured by LANXESS)
Fiber-forming fluorine-containing polymer:
Polytetrafluoroethylene (FA500C manufactured by Daikin, hereinafter abbreviated as PTFE)

  The above-mentioned various raw materials are collectively put into a tumbler at the blending ratios shown in Tables 2 and 3, and after dry mixing for 10 minutes, using a twin screw extruder (KTX37 manufactured by Kobe Steel), a melting temperature of 280 ° C. To obtain pellets of polycarbonate resin composition.

(1) Granulation property The granulation property was evaluated regarding the extrudability of the strand extruded from the tip die part of the granulator when granulating various raw materials with a twin screw extruder. The case where the stable strand was obtained was set as the pass.

(2) Flame retardancy After the various pellets obtained were dried at 125 ° C. for 4 hours, an injection molding machine (Japan Steel Works J-100SAII was used at 250 ° C. and an injection pressure of 2500 kg / cm ² for a flame retardant test. After forming a test piece (127 × 12.7 × 1.5 mm) and leaving the obtained test piece in a temperature-controlled room at a temperature of 23 ° C. and a humidity of 50% for 72 hours, Underwriters Laboratories determined. The flame retardant property was evaluated in accordance with the UL94 test (flammability test of plastic materials for equipment parts), and those satisfying V-0 as the flame retardant property of the 1.5 mm thickness test piece were accepted.

The after flame time is the length of time that the test piece after the ignition source is moved away from the flame, and the ignition of the cotton by the drip is for the sign about 300 mm below the lower end of the test piece. Of cotton is ignited by a drip from the specimen. Those satisfying V-0 were regarded as acceptable.

(3) Impact strength After various pellets obtained were dried at 125 ° C. for 4 hours, a test piece for impact test at 280 ° C. and injection pressure 1600 kg / cm ² using an injection molding machine (J-100SAII manufactured by Nippon Steel) (63.5 × 12.7 × 3.2 mm) was molded and the notched Izod impact strength was evaluated according to ASTM D-256, and the notched Izod impact strength was determined to be 30 KJ / m ² or more.

(4) Evaluation of jetness The evaluation of jetness irradiates the light of the LED light source (GEMTOS GTR-32T, brightness 26.6 lumens) on the obtained flat plate (the distance between the flat plate and the LED light source light is 10 cm), the degree of jetness was visually evaluated.
The evaluation criteria are as follows:
Good (◎): Even when illuminated by an LED light source, it glows black.
Good (◯): Even if the LED light source is irradiated, it glows black, but looks slightly whitish.
Defect (x): When an LED light source is irradiated, it glows whitish.

(5) Evaluation of optical properties After the pellets of the various resin compositions obtained were dried at 120 ° C. for 4 hours, the cylinder temperature was 280 ° C. and the mold temperature was 100 with an injection molding machine (J100E-C5 manufactured by Nippon Steel). It evaluated by measuring the light transmittance of wavelength 800nm and 900nm with the ultraviolet visible spectrophotometer (JASCO Corporation V-570) on the flat plate (90x50x2mm) condition on (degreeC). A light transmittance of 50% or more was accepted at any wavelength.

  The results of the above evaluation are shown in Tables 2 and 3.

（＊）： ５試料の全残炎時間（秒）
○： 合格 ×：不合格

(*): Total after flame time of 5 samples (seconds)
○: Pass ×: Fail

（＊）： ５試料の全残炎時間（秒）
○： 合格 ×：不合格
ＮＲ： 何れの等級にも属さない。

(*): Total after flame time of 5 samples (seconds)
○: Pass ×: Fail NR: Does not belong to any grade.

  When the polycarbonate resin composition satisfied all the constituent requirements of the present invention (Examples 1 to 6), good results were exhibited over all the evaluation items.

On the other hand, in the case where the polycarbonate resin composition does not satisfy the constituent requirements of the present invention, each case has some drawbacks.
Comparative Example 1 was inferior in jet blackness because the blending amount of the organic black dye was less than the specified amount.
In Comparative Example 2, since the blending amount of the organic black dye was larger than the specified amount, impact strength due to deterioration of the resin was observed.
Since Comparative Example 3 uses carbon black instead of the organic black dye of the present invention, it is inferior in jetness and optical properties.
The comparative example 4 was a case where the compounding quantity of a silicone compound is less than a regulation amount, and was inferior to flame retardance.
Comparative Example 5 was a case where the compounding amount of the silicone compound was larger than the specified amount, and was inferior in impact strength, jetness and optical characteristics.
In Comparative Example 6, the amount of the organometallic salt compound was greater than the specified amount, and the flame retardancy and jet blackness were inferior.
In Comparative Example 7, granulation was difficult when the amount of PTFE was greater than the specified amount.

Claims (4)

A game machine housing formed by molding a polycarbonate resin composition,
(1) The polycarbonate resin composition has 100 parts by weight of the polycarbonate resin (A), 0.05 to 1.0 parts by weight of the organic black dye (B), the main chain has a branched structure, and the organic functional group contained is aromatic. 0.01 to 5.0 parts by weight of a silicone compound (C) comprising an aromatic group or an aromatic group and a hydrocarbon group (excluding an aromatic group), 0.01 to 5.0 organometallic salt compound (D) A polycarbonate resin composition containing 2.0 parts by weight and 0.05 to 2.0 parts by weight of a fiber-forming fluoropolymer (E) as essential components;
(2) The optical characteristics of the organic black dye (B) were obtained by injection molding a resin composition comprising 100 parts by weight of the polycarbonate resin (A) and 0.3 parts by weight of the organic black dye (B). Thickness 1 obtained by measuring the light transmittance of a flat plate having a thickness of 2 mm and having a light transmittance of 50% or more in a wavelength range of 800 to 900 nm, and (3) molding the polycarbonate resin composition. When a combustion test is performed based on a UL94 test method (flammability test of plastic material for equipment parts) using a 5 mm test piece, it has a V-0 rating.
A game machine housing characterized by that.   The optical characteristics of the organic black dye (B) are 2 mm thick obtained by injection molding a resin composition comprising 100 parts by weight of the polycarbonate resin (A) and 0.3 parts by weight of the organic black dye (B). 2. The game machine housing according to claim 1, which has a light transmittance of 80% or more in a wavelength region of 800 to 900 nm when the light transmittance of the flat plate is measured.   The optical characteristics of the organic black dye (B) are 2 mm thick obtained by injection molding a resin composition comprising 100 parts by weight of the polycarbonate resin (A) and 0.3 parts by weight of the organic black dye (B). 2. The game machine housing according to claim 1, which has a light transmittance of 85% or more in a wavelength range of 800 to 900 nm when the light transmittance of the flat plate is measured.   Organometallic salt compound (D) is potassium salt of 4-methyl-N- (4-methylphenyl) sulfonyl-benzenesulfonamide, potassium diphenylsulfone-3-sulfonate, potassium diphenylsulfone-3-3｀-disulfonate 2. The game machine housing according to claim 1, wherein the housing is one or more compounds selected from the group consisting of sodium paratoluenesulfonate and potassium perfluorobutanesulfonate.