JP2005083811A - Portable explosion proof gas detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a portable explosion proof gas detector easily constituted as a small-sized one convenient to carry, having a high utility in use, sufficient in static electricity measures and having explosionproofness of high reliability. <P>SOLUTION: This portable explosionproof gas detector is constituted by providing at least a gas sensor, a signal processing circuit for processing the output signal from the gas sensor, a display mechanism for displaying the gas detection result due to the gas sensor and a power supply part for driving the signal processing circuit and the display mechanism in an elongated flat box-shaped housing held by the hand. The whole or a part of the housing is constituted of a specific antistatic resin material. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  TECHNICAL FIELD The present invention relates to an explosion-proof portable gas detection device, and more particularly, an explosion-proof portable gas gas detector having gas suction means for introducing a test gas into the device and capable of detecting a plurality of types of gas components. The present invention relates to a detection device.

In general, for example, in underground construction sites, tunnels, places where people enter, work areas, etc., there is a risk that dangerous gases such as carbon monoxide gas or hydrogen sulfide gas may be contained in the air of the environment. In many cases, there is a possibility that the air in the environmental atmosphere is in a dangerous state or in a dangerous state, such as when the oxygen gas concentration in the air may be lowered.
And when it becomes dangerous to humans due to the high concentration of dangerous gas contained in the air or low oxygen gas concentration, it is necessary to immediately know that It is.
From such a request, various types of portable gas detectors have been proposed so far.

  In general, in such a portable gas detection device, for example, by being attached to a person's body by an appropriate attachment tool, the person is transported and used together with the body. A structure in which static electricity is charged in, for example, a resin-made housing constituting the portable gas detection device due to rubbing or the like, and the risk of ignition due to this is avoided, specifically, for example, The structure needs to satisfy the conditions (a) to (c).

Condition (a): The magnitude of the insulation resistance value of the resin constituting the portable gas detector is not more than a certain value.
Condition (b): The size of the surface area of the continuous portion made of resin is not more than a certain value.
Condition (c): In relation to the device voltage, for example, the magnitude of the comparative tracking index as an index of dielectric breakdown is set to a certain value or more.
Here, the “comparative tracking index” is measured according to IEC standard 60112 (a method for determining a comparative tracking index and a tracking index of a solid electrical insulating material under wet conditions).

  Various antistatic resin materials have been conventionally proposed as the resin material constituting the housing (see, for example, Patent Document 1), but those that satisfy all of the above conditions (a) to (c) are known. Actually, for example, a resin material that satisfies the above condition (a) is used, and the size of the surface area of the continuous resin portion in the housing itself is set so as to satisfy the conditions (b) and (c). The structure is designed to prevent static electricity so that it meets the explosion-proof standards for portable (portable) gas detectors that are used in environments where there is a danger of ignition due to small restrictions. Is the actual situation (see, for example, Patent Document 2).

In addition, measures have been taken to ensure explosion-proof properties of power supply units that supply power to functional members related to gas detection, and members that surround other spaces where members having explosive energy are placed. .
For example, in a portable gas detection device driven by a battery, a plurality of rod-shaped batteries (storage batteries) are arranged side by side so that different poles are adjacent to each other and connected in series, and an insulating spacer is interposed between the batteries. A battery pack in which the battery and the entire insulating spacer are covered with a silicone rubber envelope is used in the mounted state, and the power supply portion is known to have an explosion-proof structure (see Patent Document 3). .)
JP 2002-309097 A JP 2000-209250 A Japanese Patent Laid-Open No. 08-007901

  The present invention has been made based on the circumstances as described above, and is basically easy to configure as a small and convenient to carry, high convenience in use, An object of the present invention is to provide an explosion-proof portable gas detection device that has sufficient anti-static measures and has high reliability.

The explosion-proof portable gas detection device of the present invention includes at least a gas sensor and a signal processing circuit for processing an output signal from the gas sensor in an elongated flat box-shaped housing that can be held and held by hand, In an explosion-proof portable gas detection device having a display mechanism for displaying a gas detection result by a gas sensor, and a power supply unit for driving the signal processing circuit and the display mechanism,
All or part of the housing is made of an antistatic resin material.

In the explosion-proof portable gas detection device of the present invention, the antistatic resin material is composed of the component (A) composed of a thermoplastic resin, and the thermoplastic resin that is incompatible with the component (A) at the molecular level. (B) Component, mixed resin component in which (C) component made of thermoplastic resin having polar group other than (A) component and (B) component is combined with alkali metal or alkaline earth metal A component (D) composed of a metal salt composed of a cation derived from and an anion capable of ion dissociation;
The ratio of the component (C) is 45 to 2% by weight of the mixed resin component, and the ratio of the component (D) to 100 parts by weight of the mixed resin component is 0.01 to 5 parts by weight. Preferably there is.

  In the explosion-proof portable gas detection device of the present invention, the antistatic resin material is composed of the thermoplastic resin constituting the component (A) and the thermoplastic resin constituting the component (B). When melt-kneaded as described above, it is preferable that the resin components of both the component (A) and the component (B) are in a state where the structural unit diameter is dispersed in the range of 50 nm to 500 μm.

  A molded product made of such an antistatic resin material has an insulation resistance value of 1 GΩ or less and a comparative tracking index of 90 V or more.

  In the explosion-proof portable gas detection device of the present invention, the housing may be formed of a molded product of the antistatic resin material.

  Furthermore, in the explosion-proof portable gas detection device of the present invention, a test gas suction pump that sucks a test gas from outside and supplies it to the gas sensor can be provided in the housing.

  In addition, the explosion-proof portable gas detection device of the present invention includes a plurality of gas sensors including a gas sensor including at least a catalytic combustion type gas sensor element, and power of 4.5 V is supplied from the power supply unit. It can be configured.

According to the explosion-proof portable gas detection device of the present invention, basically, the housing has a form that can be held by hand, and all the necessary components are contained in the casing. Since it is rationally arranged with the dead space as small as possible, the gas detection device itself can be made small while ensuring the necessary functions, and has excellent portability and high It is convenient, and part or all of the housing is made of a specific antistatic resin material having an insulation resistance value of 1 GΩ or less and a comparative tracking index of 90 V or more. The portable gas detector has excellent explosion-proof properties due to the antistatic property of the specific antistatic resin material itself.
In addition, the specific antistatic resin material has excellent moldability because the resin serving as the base material is a thermoplastic resin, whereby the housing or its parts can be used as a molded product, Moreover, since it has an excellent dielectric breakdown property and the insulation resistance value is sufficiently smaller than that of a resin material that has been used as a conventional suitable material, an excellent antistatic effect is exhibited. Even if the surface area of the continuous resin portion in the component part is in a large state, the portable gas detection device can be configured as having an excellent explosion-proof property.
Furthermore, since the housing or its parts can be integrally formed, the number of parts constituting the gas detection device can be reduced, and a portable gas detection device having excellent explosion-proof performance at low cost can be provided. .

  Further, by configuring the member surrounding the space in which the power supply unit and the signal processing circuit are arranged with a specific antistatic resin material, it can be configured as having a more reliable explosion-proof structure.

The present invention will be described below with reference to the drawings.
FIG. 1 is a front view showing an external appearance of a configuration example of the explosion-proof portable gas detection device of the present invention, FIG. 2 is a plan view of the explosion-proof portable gas detection device shown in FIG. 1, and FIG. 4 is a right side view of the explosion-proof portable gas detection device shown in FIG. 4, FIG. 4 is a rear view of the explosion-proof portable gas detection device shown in FIG. 1, and FIG. 5 is a bottom view of the explosion-proof portable gas detection device shown in FIG. 6 is an exploded perspective view of the explosion-proof portable gas detection device shown in FIG. 1, FIG. 7 is a sectional view taken along the line AA in FIG. 4, and FIG. 8 is a sectional view taken along the line BB in FIG. The cross-sectional views are respectively shown.
This explosion-proof portable gas detection device (hereinafter simply referred to as “gas detection device”) includes a thin and flat box-shaped housing 10 that can be held and held by a human hand. Are a rectangular frame-shaped case body 10A, a battery case 10B attached to the opening on the back side of the case body 10A, a front case 10C attached to the front end of the case body 10A, and a rear half of the battery case 10B. The battery chamber cover lid 81 is openably and closably attached to an opening that opens in the back of the battery chamber 70 formed in the portion.

  A control circuit board 11 including a gas detection signal processing circuit for processing a signal from the gas sensor and a circuit board 12 including a power feeding circuit and a charging circuit are parallel to each other on the front side inside the housing 10. Are arranged so as to extend along a flat plane of the housing 10, the front half of the housing 10 is a functional part region in which the functional members related to the gas detection operation are arranged, and the latter half is the power supply part. Is the battery part region in which is disposed.

  In FIG. 1 to FIG. 4, 16 is a filter unit for introducing the air in the target space in a state where dust is removed, and 18 is a gas discharge part provided with a gas discharge port 17 opened on the back surface.

On the front side of the control circuit board 11 in the functional part region, a panel-like display mechanism 13A composed of, for example, a liquid crystal display panel for displaying the type of gas detected and its concentration is arranged. In addition, a display unit 13 is formed, and an alarm light-emitting unit 14 is formed on each of the front end surface of the housing 10, the front region, and both side regions subsequent thereto. The alarm light-emitting unit 14 includes a light source made of a light-emitting diode (not shown) and a window plate 14A held by the housing 10 so as to cover the light source.
An operation button 15 is provided in the rear half of the front surface of the housing 10.

Further, on the back side of the control circuit board 11 in the functional area, there are a plurality of gas sensors and a pump unit which is a gas suction means for sucking the test gas from the outside and sequentially supplying it to each gas sensor. Is arranged.
More specifically, as shown in FIG. 9, five button type gas sensors SA to SE are received by the sensor holder 20 having an L-shaped gas sensor arrangement region as a whole, and gas A pump unit 40 that is a suction means is mounted and disposed in a pump unit mounting portion 21 formed at one corner adjacent to the gas sensor arrangement region in a region divided into two sides by the gas sensor arrangement region.
The pump unit 40 includes a gas suction pump 41 mounted at the front end of the pump unit mounting part 21 in the sensor holder 20 and a pump driving unit disposed along the side surface of the pump unit mounting part 21 so that the drive shaft extends in the front-rear direction. The motor 42 and a pressure sensor 43 that detects the exhaust pressure of the test gas are configured.

  In each of the gas sensors SA to SE, a sensor cap 30 is attached from the back side to a recess formed to expose the gas sensors SA to SE in the front half of the battery case 10B, and thus, in a fixed state. Is retained. Reference numeral 50 in FIGS. 1 to 3 denotes an interference gas removal filter that adsorbs and removes interference gas components from the gas sensor.

  In the gas detection device described above, at least one of the five gas sensors SA to SE is composed of, for example, a contact combustion type gas sensor element for detecting combustible hydrocarbon gas, and the dry battery 74 constituting the power supply unit or the useable battery. Electric power of 4.5 V is supplied from the rechargeable battery pack 90.

  As described above, the rear half of the inside of the housing 10 is a battery part region in which the power supply part is arranged. In this battery part region, three AA batteries 74 and a rechargeable battery described later are provided. A battery chamber 70 is formed in which either one of the packs 90 can be exchanged with the other.

10 to 13, the rechargeable battery pack 90 includes three rod-shaped rechargeable batteries (storage batteries) 91 and 91 each having the same external shape as the AA dry battery 74. , 91 are integrally formed by being held by the holding frame member 95 in a state where the adjacent ones are connected in series by the connection piece 92 with the positive and negative electrodes inverted from each other.
The holding frame member 95 has a cross-sectional shape that matches the shape of the space in the cross section orthogonal to the longitudinal direction of the battery chamber, and a positive electrode terminal 96 is formed on the rear end surface (lower end surface in FIG. 10). In addition, a negative electrode terminal 97 is formed on the front end surface (upper end surface in FIG. 10).

  In the gas detection device described above, all or part of the housing 10, specifically, the case main body 10 </ b> A, the battery case 10 </ b> B, the front case 10 </ b> C, and the battery chamber cover lid 80 are formed of molded articles made of the antistatic resin composition. It is configured.

<Antistatic resin composition>
The antistatic resin composition according to the present invention (hereinafter referred to as “specific antistatic resin composition”) is composed of a component (A) composed of a thermoplastic resin, and a non-phase at a molecular level with this component (A). A mixed resin component in which the component (B) made of a thermoplastic resin that is soluble, and the component (C) made of a thermoplastic resin having a polar group other than the component (A) and the component (B), It is preferable to contain (D) component which consists of metal salts comprised by the cation derived from an alkali metal or alkaline-earth metal, and the anion which can ionically dissociate.

  Examples of the thermoplastic resin constituting the component (A) of the specific antistatic resin composition include (meth) acrylic acid ester polymers such as polyvinyl chloride, polystyrene, and polymethyl methacrylate (PMMA), (meth) Polymer or copolymer of vinyl monomers such as acrylic acid polymer, acrylonitrile-butadiene-styrene copolymer (ABS resin); low density polyethylene, medium density polyethylene, high density polyethylene, low pressure method low density polyethylene, polypropylene, polybutene -1, poly α-olefins such as poly-4-methylpentene-1; homopolymers of α-olefins such as propylene-ethylene block copolymers, propylene-ethylene random copolymers, or α-olefins with other monomers Copolymer; Nylon 6, Nylon 4, 6, Nai Polyamides such as polyethylene 6,6, nylon 6,10, nylon 6,12, nylon 11 and nylon 12; polyesters such as polyethylene terephthalate and polybutylene terephthalate; aromatic polyethers such as polyphenylene oxide; polycarbonates; polyimides, polysulfones and poly Examples thereof include sulfone polymers such as ether sulfone.

Among these, since excellent moldability is obtained, poly (meth) acrylic acid esters such as polyvinyl chloride, polystyrene, and polymethyl methacrylate (PMMA), acrylonitrile-butadiene-styrene copolymer (ABS resin), etc. Preferred are vinyl monomer polymers or copolymers of the following: polypropylene, crystalline propylene copolymers such as crystalline propylene-ethylene copolymer and crystalline propylene-butene 1 copolymer, nylon, polybutylene terephthalate, etc. Polymers or copolymers of vinyl monomers such as vinyl chloride, polystyrene and poly (meth) acrylic acid esters are preferred.
Further, for example, in order to obtain an antistatic resin composition for general use, an acrylonitrile-butadiene-styrene copolymer (ABS resin) is preferable, and the antistatic resin composition for uses requiring transparency is used. In order to obtain, a thermoplastic resin having transparency, for example, polymethyl methacrylate (PMMA), polycarbonate, transparent ABS resin and the like are preferable.
In addition, polycarbonate, polyethylene terephthalate, aromatic polyimide, aromatic polyether and the like are preferable because excellent heat resistance can be obtained.

The component (B) constituting the specific antistatic resin composition may be any thermoplastic resin that is incompatible with the thermoplastic resin constituting the component (A) used at the molecular level. For example, the thermoplastic resin exemplified as constituting the component (A) can be selected and used, but when the components (A) and (B) are melt-kneaded at a melting temperature or higher of each component In addition, it is preferable that the resin component of both the component (A) and the component (B) is a combination in which the average structural unit diameter is dispersed in the form of structural units in the range of 50 nm to 500 μm.
For example, when acrylonitrile / butadiene / styrene copolymer (ABS resin) is used as component (A), one or more of polystyrene resin and polycarbonate resin (PC) should be used in combination as component (B). Is preferred.
When polyvinyl chloride resin (PVC) is used as component (A), methacrylic acid / butadiene / styrene copolymer (MBS), polymethyl methacrylate (PMMA), ABS resin, acrylic as component (B) It is preferable to use a combination of one or more types of rubber.

Furthermore, when polybutylene terephthalate (PBT) is used as the component (A), it is preferable to use at least one of polyethylene terephthalate (PET) and polycarbonate resin (PC) in combination as the component (B).
Moreover, when polymethylmethacrylate (PMMA) is used as the component (A), it is preferable to use a combination of one or more of acrylic rubber and polycarbonate resin as the component (B).
Moreover, when a nylon resin (PA) is used as the component (A), it is preferable to use a combination of one or more of an ABS resin and a polycarbonate resin as the component (B).

The component (C) constituting the specific antistatic resin composition is a thermoplastic resin other than the components (A) and (B) used, and has a polar group in the molecular structure. Any material may be used, but for example, a thermoplastic elastomer is preferable.
Examples of the thermoplastic elastomer include polyether ester amide resins, polyester elastomers, aliphatic polyesters, polyurethane elastomers, and polyamide elastomers, and among these, polyether ester amide resins are particularly preferable.
The thermoplastic resin of component (C) preferably has a glass transition temperature of 60 ° C. or lower, more preferably 50 ° C. or lower, particularly preferably 40 ° C. or lower, and more preferably 30 ° C. or lower. When a thermoplastic resin having a glass transition temperature exceeding 60 ° C. is used as the component (C), it is difficult to obtain a resin material having a sufficient antistatic effect.

(C-1) polyetheresteramide resin;
The polyether ester amide resin used as the component (C) in a specific antistatic resin composition is one kind of a high molecular nonionic surfactant having a polyether segment. Specifically, for example, Antistatic elastomer having polyether segment such as polyethylene glycol / polyamide copolymer, polyethylene glycol / methacrylate copolymer, polyethylene oxide / polypropylene oxide copolymer, polyethylene glycol polyester amide copolymer, polyethylene glycol polyester elastomer Etc. can be illustrated.
In particular, polyether ester amide resins derived from polyamides having carboxyl groups at both ends and alkylene oxide adducts of bisphenols and / or polyoxyalkylene glycols are preferred.

(C-2) polyester elastomer;
In the polyester elastomer used as the component (C) in a specific antistatic resin composition, the hard segment in the molecule is formed of polyester, and the soft segment is formed of polyether or polyester having a low glass transition temperature (Tg). More specifically, for example, a polyester / polyether type hard segment in which a hard segment is formed of an aromatic crystalline polyester such as polybutylene terephthalate and a soft segment is formed of a polyether, a hard segment Can be exemplified by those of polyester / polyester type wherein is formed of an aromatic crystalline polyester and the soft segment is formed of an aliphatic polyester.

The polyester / polyether type polyester elastomer is synthesized by transesterification and polycondensation reactions using, for example, dimethyl terephthalate, 1,4-butanediol and polytetramethylene ether glycol as starting materials.
The polyester / polyether type polyester elastomer can also be synthesized by transesterification and ring-opening reactions using dimethyl terephthalate, 1,4-butanediol, and ε-caprolactone as starting materials.
In the specific antistatic resin composition according to the present invention, any ordinary polyester elastomer can be used, and one kind can be used alone, or two or more kinds can be used in combination.

(C-3) aliphatic polyester;
As the aliphatic polyester used as the component (C) in the specific antistatic resin composition, those that are generally commercially available as biodegradable can also be used. For example, the product name “Bionore” (polybutylene succinate, polybutylene succinate adipate) sold by Showa Polymer Co., Ltd. and “Cell Green” (polycaprolactone) sold by Daicel Chemical Industries, Ltd. However, it is possible to arbitrarily select a resin according to the application and characteristics. Industrially, those synthesized by a dehydration polycondensation reaction and a dediol reaction using an aliphatic dicarboxylic acid and an excess diol as starting materials can be mentioned. As such aliphatic polyesters, polybutylene succinate, polyethylene succinate and copolymers thereof are common, and various high molecular weight types are industrially produced.

Examples of the aliphatic polyester suitably used as the component (C) in the specific antistatic resin composition include polybutylene succinate (binary condensate of succinic acid and 1,4-butanediol), polybutylene. And succinate adipate (a ternary condensate of succinic acid and adipic acid and 1,4-butanediol).
In addition, a reactive group such as an isocyanate group or a urethane group can be introduced into the structure of the aliphatic polyester. Furthermore, a copolymer such as a copolyester obtained by copolymerizing polylactic acid can also be used as the aliphatic polyester.

(C-4) polyurethane elastomer;
The polyurethane elastomer used as the component (C) in the specific antistatic resin composition is a thermoplastic elastomer having a urethane group, and a soft segment is formed of polyurethane obtained by a reaction of a long-chain glycol and an isocyanate. Is a linear multi-block copolymer formed of a polyurethane composed of a short-chain glycol and an isocyanate, and may be obtained by using a cross-linking agent or a chain extender, if necessary.
Here, as a general classification according to the type of the long-chain glycol, the polyether type includes polyethylene oxide, polypropylene oxide, or a copolymer thereof, and the polyester type includes polyadipate, Examples of the polylactone, polycarbonate, and aliphatic group include polybutadiene and polyisoprene.

Short chain glycols include aliphatic glycols such as ethylene glycol, 1,4-butanediol and 1,6-hexanediol, alicyclic glycols such as cyclohexanedimethanol, and hydroquinone bis (2-hydroxyethyl). Aromatic glycols such as ethers are usually used.
On the other hand, 4,4'-diphenylmethane diisocyanate (MDI), 2,4'-toluene diisocyanate and / or 2,6-toluene diisocyanate (TDI), etc. are used as the isocyanate.
In addition, as the cross-linking agent (chain extender), aromatic diamines such as 3,3-dichloro-4,4-diaminodiphenylmethane (MOCA) are used.
The said polyurethane elastomer can be used individually by 1 type or in combination of 2 or more types.

(C-5) polyamide elastomer;
The polyamide used as the component (C) in the specific antistatic resin composition is a generic name for amide resins having an amide bond in its repeating unit. Specifically, for example, nylon 6, nylon 6,6 Examples thereof include nylon 12, polyamide polyester copolymer, polyamide polyether copolymer and the like.
The polyamide elastomer used as the component (C) in a specific antistatic resin composition is a general term for a polyamide constrained phase that is a hard segment, and a thermoplastic elastomer that has a polyether or polyester structure as a soft segment. (PA) A polyamide elastomer using a PA12 component as a constrained phase is obtained by reacting laurolactam, dicarboxylic acid, and polyether diol with water as a lactam ring-opening catalyst and under pressure and heating to produce carboxyl telechelic nylon 12 There is a method in which an oligomer is obtained and then a thermoplastic elastomer is obtained by a condensation reaction with a polyether diol. In addition to this, PA6 or the like is also used as the polyamide constrained phase.

  The polyamide elastomer is basically in the form of a polyether block polyamide elastomer or a polyether ester block polyamide elastomer by the above synthesis method. Here, polyamide elastomers having various characteristics can be obtained depending on the kind of diol used in the synthesis method.

  In the specific antistatic resin composition, the blending ratio of the component (B) is 3 to 50 parts by weight with respect to 50 to 97 parts by weight of the component (A), provided that (A) and (B) Is 100 parts by weight. It is preferable that it is 20 to 50 parts by weight with respect to 50 to 80 parts by weight of component (A). When the blending ratio of the component (B) is too small or too large, it becomes difficult to obtain a resin material having a sufficient antistatic effect.

  The blending ratio of the component (C) is 45 to 2% by weight of the mixed resin component, that is, 45 to 2 parts by weight with respect to the total 55 to 98 parts by weight of the component (A) and the component (B) [however, The total of component (A), component (B) and component (C) is 100 parts by weight. More preferably, it is 35 to 3 parts by weight with respect to a total of 65 to 97 parts by weight of the component (A) and the component (B), and more preferably the component (A) and the component (B). 30 to 5 parts by weight based on 70 to 95 parts by weight of the total components. When the blending ratio of the component (C) exceeds 45 parts by weight, there are problems that the moldability is remarkably deteriorated and that the mechanical properties of the matrix resin (A) component and the component (B) are greatly deteriorated. On the other hand, when the blending ratio of the component (C) is less than 2 parts by weight, the antistatic property can hardly be exhibited.

Examples of the alkali metal or alkaline earth metal that becomes a cation constituting the metal salt of the component (D) related to the specific antistatic resin composition include Li, Na, K, Mg, Ca, and the like. As the cation, Li ⁺ , Na ⁺ and K ⁺ having a small ionic radius are preferable.
Examples of the ion dissociable anion constituting the metal salt of the component (D) relating to the specific antistatic resin composition include Cl ⁻ , Br ⁻ , F ⁻ , I ⁻ , NO ₃ ⁻ , SCN ^−. , ClO ₄ ⁻ , CF ₃ SO ₃ ⁻ , BF ₄ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (CF ₃ SO ₂ ) ₃ C ^{− and the} like. Preferably, ClO ₄ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (CF ₃ SO ₂ ) ₃ C ^{− and the} like can be exemplified.
There are many metal salts composed of the above cations and anions. Among them, LiClO ₄ , Na ClO ₄ , Mg (ClO ₄ ) ₂ , KClO ₄ , (CF ₃ SO ₃ ) Li, (CF ₃ SO ₂ ) ₂ NLi, (CF ₃ SO ₂ ) ₂ NNa, (CF ₃ SO ₂ ) ₃ CLi, and (CF ₃ SO ₂ ) ₃ CNa are preferred, with LiClO ₄ and Na ClO ₄ being particularly preferred.

  The ratio of (D) component which concerns on specific antistatic resin composition is 0.01-5 with respect to 100 weight part of total (mixed resin component) of (A) component, (B) component, and (C) component. The amount is preferably parts by weight, and more preferably 0.05 to 0.5 parts by weight with respect to 100 parts by weight in total of the component (A), the component (B) and the component (C). When the proportion of component (D) is less than 0.01 parts by weight, sufficient antistatic properties cannot be obtained. On the other hand, when the proportion of the component (D) exceeds 5 parts by weight, the antistatic effect is not improved. On the other hand, the progress of crystallization and material deterioration are caused, and the antistatic effect is lowered.

In the specific antistatic resin composition according to the present invention, various fillers, stabilizers, colorants, reinforcing rubber, other elastomer components, plasticizers, dispersants, ultraviolet absorbers, as appropriate, depending on the purpose. Additives such as antioxidants, flame retardants, stabilizers, reinforcing agents, lubricants, foaming agents, weathering agents (lightproofing agents), and metal powders can be blended.
In addition, the specific antistatic resin composition according to the present invention can be used in a wide range of applications other than portable gas detection devices such as electricity, electrical equipment members, printer members, scanner members, and OA equipment members such as copying machines. Can also be applied.

  The specific antistatic resin composition according to the present invention can be applied to all molding methods, and can be molded by various molding machines such as extrusion molding, injection molding, blow molding, calendar molding, vacuum molding, and emboss molding. .

  In a molded article made of the specific antistatic resin composition as described above, the insulation resistance value is 1 GΩ or less and the comparative tracking index is 90 V or more, thereby having excellent antistatic properties.

  In the gas detection device, the gas to be detected discharged from the gas suction pump 41 is sequentially supplied to each of the gas sensors SA to SE to detect the detection target gas, and the gas detected by the display unit 13 is detected. Are displayed, and when it is detected that the concentration of any of the detection target gases exceeds the reference value, an alarm is generated by the light emission of the alarm light emitting unit 14.

In addition, as a warning notification mechanism, a warning buzzer and a warning vibration generator (which emits a low frequency of about several tens of hertz) can be provided. In this case, a buzzer sound by a warning buzzer, An alarm is generated by light emission by the alarm light emitting element and vibration by the alarm vibration generator.
When a plurality of types of alarm notification mechanisms are provided, it is not necessary for all of them to be driven all at once, and a cyclic alarm operation is performed in which each alarm notification mechanism is sequentially driven for a predetermined time. Preferably, according to such drive control, it is possible to suppress the consumption of the battery as compared with the case of being driven all at once.

Thus, according to the gas detection device described above, basically, the housing 10 has a form that can be held and held, and all the necessary components are contained in the housing 10. Therefore, the gas detection device itself can be made small in size while ensuring the necessary functions. In addition, the case body 10A, the battery case 10B, the front case 10C, and the battery chamber cover lid 81 constituting the housing 10 have an insulation resistance value of 1 GΩ or less and a comparative tracking index. By comprising a specific antistatic resin material of 90 V or higher, the gas detection device is prevented by the antistatic property of the specific antistatic resin material itself. Explosion proof is obtained with excellent meet the criteria for sex.
In addition, the specific antistatic resin material has excellent moldability because the base resin is a thermoplastic resin, whereby the case body 10A, the battery case 10B, Each of the front case 10C and the battery chamber cover lid 81 can be used as a molded product, and the specific antistatic resin material has an excellent dielectric breakdown property and an insulation resistance value that is conventionally suitable. Since it is sufficiently smaller than the resin material used, an excellent antistatic effect is exhibited, and therefore the surface area of the continuous resin portion in the housing 10 or its component parts is a portable gas detector. even those with the reference value, for example 100 cm ² greater than the state of the explosion-proof for (resin container constituting the gas sensing device), gas detector It can be configured as having an excellent explosion proof.
Furthermore, since the housing 10 or its parts can be integrally molded, the number of parts constituting the gas detection device can be reduced, and a portable gas detection device having an excellent explosion-proof property can be obtained at low cost. .

  Further, the case main body 10A and the battery case 10B surrounding the space where the power supply unit and the signal processing circuit are arranged are made of a specific antistatic resin material, so that the gas detection device has a more reliable explosion-proof structure. It can comprise as what has.

  In addition, since a power of 4.5 V is supplied from the three AA dry batteries 74 or the rechargeable battery pack 90, relatively large power is secured as a portable type. Therefore, a catalytic combustion type gas sensor element can be used for at least one of the plurality of gas sensors. This increases the degree of freedom in selecting a detectable gas component, and provides high convenience.

As mentioned above, although preferred embodiment which concerns on this invention was described, this invention is not limited to said embodiment, A various change can be added.
For example, in the housing of the gas detection device, the functional part region may be formed in the front half and the battery part region may be formed in the rear half, and the arrangement of other members is arbitrary. Further, the dry battery used as the driving power source is not limited to the AA type.
In addition, the gas detection device may be used while being held in the hand, or may be used directly on a person's body using an appropriate wearing member or on a person's clothes. Examples of the member include a clip and a pin. Depending on the form, the mounting member may be formed integrally with the casing. Further, the mounting member can be configured to be easily replaceable.

  Hereinafter, the present invention will be described with reference to specific examples and comparative examples, but the present invention is not limited to these examples. In the examples, parts and% are based on weight unless otherwise specified.

<Preparation of test piece>
A test piece was molded from the sample pellet by an injection molding machine having a clamping force of 80 ton. The molding conditions were a cylinder temperature of 200 to 270 ° C. and a mold temperature of 30 to 60 ° C.

<Measurement of physical properties>
After adjusting the test piece for 24 hours in an environment of room temperature 23 ± 2 ° C. and relative humidity 50%, the following physical properties were measured.

  (1) Flexural strength (flexural modulus); The flexural modulus was measured according to ASTM D760. The unit in the following table is [MPa].

  (2) Izod (IZOD) impact strength; Izod impact strength was measured according to ASTM D256 using a test piece with a thickness of 1/4 inch and notch. The unit in the following table is [J / m].

  (3) Surface resistivity: Surface resistivity was measured by ASTM D257 using “HIRESTA” manufactured by Mitsubishi Chemical Corporation using an injection molded test piece having a width of 6 cm, a length of 6 cm and a thickness of 0.3 cm. The measurement was performed according to the above.

  (4) Insulation resistance; insulation resistance is the insulation resistance performance of plastic parts required by the technical standards of the Ministry of Health, Labor and Welfare and explosion-proof electrical equipment (Explosion-proof electrical machinery / equipment type verification guide 1.2.2: Technology) The measurement was carried out in accordance with standard standards. The measurement conditions were a test piece having a width of 60 mm and a length of 150 mm, a measurement temperature of 23 ° C., a measurement relative humidity of 50 RH%, and an applied voltage of DC 500 V.

  (5) Comparative tracking index: The comparative tracking index was measured in accordance with IEC 60112 PTI value measurement. The measurement conditions were a test piece having a width of 30 mm, a length of 30 mm, and a thickness of 3.2 mm, a measurement temperature of 21 ° C., and a measurement relative humidity of 45 RH%.

(6) Formability and surface smoothness Using an 11-point gate mold having a width of 13 cm, a length of 32 cm, and a thickness of 0.5 cm, the sample pellets were subjected to a cylinder temperature of 200 to 200 by an injection molding machine having a clamping force of 220 tons. A molded product was produced at 270 ° C. and a mold temperature of 30 ° C. to 60 ° C. The state of the molded product was observed and evaluated as follows.
[Formability]
The moldability (comprehensive judgment of fluidity, releasability, short, sprue breakage, etc.) of the molded product was evaluated according to the following criteria.
“A”: Very good “B”: Moldable “C”: Moldable, but stable molding operation cannot be performed.
“D”: Molding impossible [Appearance of molded product (surface smoothness)]
The overall judgment of the smoothness, glossiness, weld mark, flash mark, fluffing, etc. of the molded product was evaluated by visually observing the molded product according to the following criteria.
“A”: Very good “B”: Usable “C”: Usable for general-purpose parts but unsuitable for precision parts “D”: Not usable

The materials used in this example are as follows.
<Thermoplastic resin>
(A) thermoplastic resin for component;
(A-1): ABS resin (manufactured by Technopolymer Co., Ltd., trade name “Techno ABS330”) (B) thermoplastic resin for component;
(B-1) Polycarbonate resin (trade name “Iupilon S-2000”)
(B-2) Polystyrene resin (manufactured by A & M Styrene Co., Ltd., trade name “GPPSG8259”)
Mixed resin of component (A) and component (B);
(A + B): ABS / PC composite resin (manufactured by Technopolymer Co., Ltd., trade name “Excelloy CK10” (ABS / PC alloy grade, ABS / PC = 2/1, particle diameter of each component: 500 nm to 100 μm (resin temperature) This is a result obtained by measuring a molded product obtained by molding at 220 ° C. with an electron micrograph.))
(C) thermoplastic resin for component;
(C-1): Polyetheresteramide (manufactured by Sanyo Chemical Industries, Ltd., trade name "Perestat NC6321"(Tg; -45 ° C to -55 ° C))
<Metal salts>
(D) component;
(D-1): Bis (trifluoromethanesulfonyl) imidolithium: (CF ₃ SO ₂ ) ₂ NLi
<Other ingredients>
Organic compound: bis [2- (2butoxyethoxy) ethyl] adipate Inorganic filler: Talc: manufactured by Takehara Chemical Co., Ltd., trade name “talc TT” (average particle size: 7 μm)

[Example 1]
85 parts by weight of (A + B), 15 parts by weight of (C-1), 0.2 parts by weight of (D-1), and 0.8 parts by weight of bis [2- (2butoxyethoxy) ethyl] adipate were added using a tumbler mixer. Preliminarily dry blended, and melt kneaded at a melting temperature of 220 to 270 ° C. by a 47 mm same-direction twin screw extruder. The string-shaped resin melt mixture that came out of the die was cooled in a water tank, and passed through a cutter to produce pellets of the antistatic resin composition. The results are shown in Table 1.

[Example 2]
(A + B) 65 parts by weight, (C-1) 35 parts by weight, (D-1) 0.7 parts by weight, bis [2- (2butoxyethoxy) ethyl] adipate 3.8 parts by weight, and talc 15 parts by weight Was preliminarily dry-blended with a tumbler mixer, and melt kneaded at a melting temperature of 220 to 270 ° C. with a 47 mm same-direction twin screw extruder. The string-shaped resin melt mixture that came out of the die was cooled in a water tank, and passed through a cutter to produce pellets of the antistatic resin composition. The results are shown in Table 1.

Example 3
After 40 parts by weight of (A-1) and 40 parts by weight of (B-1) were melt kneaded at a melting temperature of 240 to 270 ° C. by a 47 mm co-directional twin-screw extruder and pelletized, (C-1 ) 20 parts by weight, (D-1) 0.2 parts by weight, and bis [2- (2butoxyethoxy) ethyl] adipate 0.8 parts by weight were pre-dry blended with a tumbler mixer, and 47 mm co-directional twin screw extrusion Melt kneading was performed at a melting temperature of 220 to 270 ° C. using a machine. The string-shaped resin melt mixture that came out of the die was cooled in a water tank, and passed through a cutter to produce pellets of the antistatic resin composition. The results are shown in Table 1.

Example 4
(A-1) 28 parts by weight, (B-2) 65 parts by weight, (C-1) 7 parts by weight, (D-1) 0.2 parts by weight, and bis [2- (2butoxyethoxy) ethyl] 0.8 parts by weight of adipate was preliminarily dry blended with a tumbler mixer, and melt kneaded at a melting temperature of 240 to 270 ° C. with a 47 mm same-direction twin screw extruder. The string-shaped resin melt mixture that came out of the die was cooled in a water tank, and passed through a cutter to produce pellets of the antistatic resin composition. The results are shown in Table 1.

[Comparative Example 1] (Example in which component (B) is not synthesized)
(A-1) 85 parts by weight, (C-1) 15 parts by weight, (D-1) 0.2 parts by weight, and bis [2- (2butoxyethoxy) ethyl] adipate 0.8 parts by weight Preliminary dry blending was performed with a mixer, and melt kneading was performed at a melting temperature of 240 to 270 ° C. using a 47 mm same-direction twin screw extruder. The string-shaped resin melt mixture that came out of the die was cooled in a water tank, and passed through a cutter to produce pellets of the antistatic resin composition. The results are shown in Table 1.

[Comparative Example 2] (Example in which component (A) is not synthesized)
(B-2) 93 parts by weight, (C-1) 7 parts by weight, (D-1) 0.2 parts by weight, and bis [2- (2butoxyethoxy) ethyl] adipate 0.8 parts by weight Preliminary dry blending was performed with a mixer, and melt kneading was performed at a melting temperature of 240 to 270 ° C. using a 47 mm same-direction twin screw extruder. The string-shaped resin melt mixture that came out of the die was cooled in a water tank, and passed through a cutter to produce pellets of the antistatic resin composition. The results are shown in Table 1.

As is clear from the above results, the antistatic resin compositions of Examples 1 to 4 basically have excellent mechanical properties (flexural modulus, strength) and excellent moldability and surface. It has been confirmed that it has smoothness and excellent antistatic properties, and is thereby extremely useful as a material constituting the housing of a portable gas detection device or its components.
In contrast, the antistatic resin compositions of Comparative Example 1 and Comparative Example 2 have excellent mechanical properties (flexural modulus, strength) and excellent moldability and surface smoothness. The value was as extremely large as 1 GΩ or more, and it was confirmed that the antistatic property that satisfies the regulations regarding the explosion-proof property related to the portable gas detector is not sufficiently developed.

It is a front view which shows the external appearance in the example of 1 structure of the explosion-proof portable gas detection apparatus of this invention. It is a top view of the explosion-proof portable gas detection apparatus shown in FIG. It is a right view of the explosion-proof portable gas detector shown in FIG. It is a rear view of the explosion-proof portable gas detection apparatus shown in FIG. It is a bottom view of the explosion-proof portable gas detector shown in FIG. It is a disassembled perspective view of the explosion-proof portable gas detector shown in FIG. It is sectional drawing of the AA cross section in FIG. It is sectional drawing of the BB cross section in FIG. It is a perspective view which shows the structure of a sensor holder in the state in which the gas sensor and the pump unit were mounted | worn with the said sensor holder. It is a top view which shows one structural example of a rechargeable battery pack. It is a front view of the rechargeable battery pack shown in FIG. It is a rear view of the rechargeable battery pack shown in FIG. It is sectional drawing of CC cross section in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Housing 10A Case main body 10B Battery case 10C Front case 11 Control circuit board 12 Circuit board 13 Display part 13A Panel-like display mechanism 14 Alarm light emission part 14A Window plate 15 Operation button 16 Filter unit 17 Gas exhaust port 18 Gas exhaust part SA to SE Gas sensor 20 Sensor holder 21 Pump unit mounting part 30 Sensor cap 40 Pump unit 41 Gas suction pump 42 Pump drive motor 43 Pressure sensor 50 Filter assembly 70 Battery chamber 74 Dry cell 80 Battery chamber cover lid 90 Rechargeable battery Pack 91 Rechargeable battery 95 Holding frame member 96 Positive terminal 97 Negative terminal

Claims (7)

At least a gas sensor, a signal processing circuit for processing an output signal from the gas sensor, a display mechanism for displaying a gas detection result by the gas sensor, in an elongated flat box-shaped housing that can be held and held by a hand, And in the explosion-proof portable gas detection device having a power supply unit for driving the signal processing circuit and the display mechanism,
An explosion-proof portable gas detection device, wherein all or part of the housing is made of an antistatic resin material. The antistatic resin material is a component (A) composed of a thermoplastic resin, a component (B) composed of a thermoplastic resin that is incompatible with the component (A) at the molecular level, and the component (A) and (B) It is comprised by the mixed resin component which the (C) component consisting of the thermoplastic resin which has a polar group other than a component was combined, the cation derived from an alkali metal or alkaline-earth metal, and an ion dissociable anion. (D) component which consists of the metal salt which is,
The ratio of the component (C) is 45 to 2% by weight of the mixed resin component, and the ratio of the component (D) to 100 parts by weight of the mixed resin component is 0.01 to 5 parts by weight. The explosion-proof portable gas detection device according to claim 1, wherein the explosion-proof portable gas detection device is provided.   When the antistatic resin material is melt-kneaded with the thermoplastic resin constituting the component (A) and the thermoplastic resin constituting the component (B) above the melting temperature of each component, the component (A) and ( The explosion-proof portable gas detection device according to claim 1 or 2, wherein both resin components of component B) are dispersed in a structural unit diameter range of 50 nm to 500 µm.   The explosion-proof portable gas detection according to any one of claims 1 to 3, wherein the antistatic resin material has an insulation resistance value of 1 GΩ or less and a comparative tracking index of 90 V or more. apparatus.   The explosion-proof portable gas detection device according to any one of claims 1 to 4, wherein a housing is formed of a molded product of the antistatic resin material.   The explosion-proof type according to any one of claims 1 to 5, wherein a test gas suction pump for sucking a test gas from outside and supplying the gas to a gas sensor is provided in the housing. Portable gas detector.   7. The apparatus according to claim 1, further comprising a plurality of gas sensors including a gas sensor including at least a catalytic combustion type gas sensor element, wherein electric power of 4.5 V is supplied from a power supply unit. Explosion-proof portable gas detector described in 1.

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