JPH04144195A - Box for electronic apparatus - Google Patents

Abstract

PURPOSE:To prevent malfunction by a method wherein an aspiration material containing a mixture of a high humidity absorbing and releasing material, in which metal ions are included in water-soluble polymers in a colloid state, and water-insoluble polymers is provided within a box. CONSTITUTION:An aspiration material 1 has hygroscopic capacity that is several times more than that of desiccating agent such as silica gel depending on the composition of the aspiration material 1, and the capacity of the box 2 is limited. Moreover, the amount of humidity absorption can be adjusted by changing the components of the aspiration material 1 so that the inside of the box does not reach the amount of saturation water vapor without dew condensation within the box that will result in malfunction. Moreover, even if the aspiration material itself reaches the amount of the saturation water vapor, the aspiration material 1 will be set in an aspiration state where it literally repeats the humidity absorption and release so that it is possible to prevent the dew condensation and malfunction beforehand by maintaining the humidity at a level without allow it to reach the amount of the saturation water vapor.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a housing for electronic equipment that can prevent malfunctions even if sudden changes in temperature and humidity occur.

[Conventional technology] Traditionally, stoves and the like have been used indoors in winter.
It heats up the room. This kind of warm air occurs during the day when humans are active, and at night, when people go to bed, they turn off stoves and other appliances. For example, if you use the stove like this, per hour,
Generates about 400 grams of water vapor. Therefore, tsn occurs indoors that is cooled by outside air late at night. This phenomenon is noticeable on window glass and the like with poor heat insulation ability, but condensation also occurs in electronic devices installed indoors, causing malfunctions.

Additionally, on rainy winter days, high humidity and low temperatures can cause condensation to form inside car audio equipment, causing malfunctions.

As described above, dew condensation is particularly likely to occur in winter when the temperature is low and the amount of saturated water vapor is low, causing malfunction of electronic equipment.

Therefore, if you prevent dew condensation from occurring, you can prevent the above malfunctions, so it is possible to use a water-absorbing polymer to absorb the condensed water. It is impossible to do so, and even if it could be arranged, water-absorbing polymers mainly absorb water in the form of water, so fog formation occurs, and it is impossible to completely absorb water. Even if polymers are used, malfunctions cannot be prevented.

As described above, there is still no effective method for preventing dew condensation inside electronic devices, and there is an urgent need to establish a method for preventing dew condensation and malfunctions.

[Problems to be Solved by the Invention] An object of the present invention is to provide a housing that is excellent in preventing malfunctions.

[Means for Solving the Problems] A casing provided inside the casing with a breathing material 1 containing a mixture of a highly moisture-absorbing and desorbing material in which a water-soluble polymer contains metal ions in a colloidal state and a poorly water-soluble polymer. With body 2, it is possible to prevent dew condensation within the housing, and as a result, malfunctions can be prevented.

In addition, if a spacer 3 is interposed between the breathing material 1 and the housing 2, or if the breathing material 1 is pleated so that both sides of the breathing material 1 can be used, the ability to prevent malfunction will be improved.

[Function J] Since the electronic device casing of the present invention includes the breathing material 1 inside the casing, it exhibits excellent dew condensation prevention performance and can prevent malfunctions. In other words, the respiratory material 1 used in the present invention has several times the moisture absorption capacity of conventional desiccant agents such as silica gel, although it differs depending on the constituent components of the respiratory material 1. Furthermore, the amount of moisture absorbed can be adjusted by changing the components of the breathing material 1, so that the inside of the casing does not reach the saturated amount of water vapor and condensation does not occur inside the casing. occurs, and will not cause malfunction. Even if the breathing material itself reaches its saturated moisture absorption amount, the breathing material 1 used in the present invention will literally be in a breathing state where it repeatedly absorbs and releases moisture. It is possible to prevent dew condensation and malfunctions by preventing the amount of water vapor from exceeding the amount.

Further, the breathing material 1 not only functions to absorb and release moisture as described above, but also functions as a heat insulating layer that reduces the temperature difference between the inside and outside of the casing, making it more difficult for dew condensation to occur.

Since the respiratory material 1 of the present invention contains a mixture of a highly moisture-absorbing and desorbing material in which metal ions are included in a colloidal state in a water-soluble polymer and a poorly water-soluble polymer, excess moisture is absorbed and the respiratory material itself becomes saturated. 6. Breathing material 1 of the present invention exhibits excellent moisture absorption and release properties due to the action of highly moisture absorption and release materials, and is poorly water soluble. It is morphologically stable because it is fixed by a polymer.

Since the breathing material 1 of the present invention is composed of a highly moisture-absorbing and desorbing material and a poorly water-soluble polymer, it is thought that the poorly water-soluble polymer inhibits the moisture absorption and desorption properties of the highly moisture-absorbing and desorbing material. It is an excellent material with almost no decrease in moisture. The reason why this moisture absorption and desorption property does not decrease is because the poorly water-soluble polymer is in a dispersed state, and the highly moisture absorption and desorption material is in a colloidal state, so even if a mixture of these two types is dried after being uniformly dispersed, W! ? ! From a physical perspective, it is in an aggregated state with micropores, and it is thought that moisture can be absorbed and released through these micropores.

The highly moisture-absorbing and desorbing material used in the present invention is one in which metal ions are included in a colloidal state in a water-soluble polymer.

The water-soluble polymer in the highly moisture-absorbing and desorbing material includes all water-soluble natural polymers, semi-synthetic polymers, and synthetic polymers.

A colloidal state means a state in which metal ions are dispersed in a water-soluble polymer when a highly moisture-absorbing and desorbing material is dissolved in water. This state means that the absorption wavelength obtained from the absorbance analysis performed by dissolving the highly hygroscopic material in water and the absorption wavelength obtained from the absorbance analysis when the metal salt is simply dissolved in water are almost the same. You can check from When a highly moisture-absorbing and desorbing material is dissolved in water, it swells with excessive moisture and becomes a viscous liquid like a sol, which is completely different from the state in which a metal salt is simply dissolved in water. They are in different states.

When a metal ion and a water-soluble polymer form a chelate, that is, when they have a coordination bond, they should show absorption at a different wavelength from the absorption wavelength obtained by simply dissolving the metal salt in water. However, when the highly moisture-absorbing and desorbing material of the present invention is dissolved in water, it exhibits the same absorption wavelength as when the metal salt is simply dissolved in water.
In other words, it is considered to be in the same state as the colloidal state of metal ions, and no chelate is formed.

The highly moisture-absorbing and desorbing material used in the present invention is stable and does not change before and after drying even through the drying process.
Absorbance analysis may be performed before drying during the manufacturing process, or
The highly moisture-absorbing and desorbing material may be dissolved in water again. Note that the degree of dissolution of the highly moisture-absorbing and desorbing material in water is a degree that can be analyzed by absorbance analysis, and varies depending on the metal salt, water-soluble polymer, etc. used.

Since the highly moisture-absorbing and desorbing material of the present invention uses a water-soluble polymer, water tends to collect in the polar portion of the water-soluble polymer.

In other words, water droplet atoms of water molecules with low electron density are likely to be electrostatically attracted to areas with high electron density. After the water molecules are attracted, the hydration power of the metal ions dispersed in the highly moisture-absorbing and desorbing material exceeds the electrostatic force, so the collected water moves toward the metal ions, causing the metal ions to move toward the metal ions. The metal ions are also held electrostatically in the polar portion inside the water-soluble polymer.

Conversely, when the humidity of the outside air decreases or becomes dry, the vapor pressure of the outside air decreases, and the force due to the vapor pressure difference is stronger than the hydration force of metal ions, and the highly hygroscopic material of the present invention absorbs moisture. Release moisture. In other words, the water hydrated by the metal ions moves to the polar portion of the water-soluble polymer, contrary to the case of moisture absorption, and is then released into the atmosphere.

In addition, when the highly hygroscopic material used in the present invention reaches a saturated state of moisture absorption, it repeats moisture absorption and desorption in that state. This is because the interaction of water molecules with metal ions after reaching a saturated state is weak, and moisture desorption occurs easily.

In other words, the high moisture releasing material of the present invention releases excess moisture,
When moisture absorption reaches a saturated state, the body repeats moisture absorption and release, reaching an equilibrium state similar to breathing.

In this way, in an equilibrium state, it not only absorbs moisture but also releases moisture, making it possible to maintain a constant humidity level. In addition,
This humidity that is kept constant depends on the type of highly moisture-absorbing material, that is,
It can be adjusted by changing the FGs of the water-soluble polymer constituting the high moisture absorption/desorption material, the type of metal ion, the amount of metal ion mixed, and the amount of impregnation when impregnating the base material.

Hereinafter, metal ions and water-soluble polymers will be specifically explained.

Examples of metal ions used in the highly moisture absorbing and desorbing material include lithium ions, calcium ions, iron ions, aluminum ions, magnesium ions, chromium ions, cobalt ions, cadmium ions, zinc ions, and nickel ions.

Examples of metal salts that provide these metal ions include calcium chloride [CaCL], iron chloride (■) hexahydrate [F
eC15(6)ItO)], aluminum nitrate (lI
I19 hydrate [AltNo-)a(9HmO)], Magnesium chloride hexahydrate [MgC1m[6HtO1], Zinc chloride [ZIIC1t], Limonium chloride (In) hexahydrate [CrcI3(auxo+Co, Cobalt chloride+1+16)
hydrate [CoC1-(6[120>]], cadmium (Il) nitrate tetrahydrate [Cd(NOa)x(4H20)], nickel (II) chloride hexahydrate [N+C1z(6[1xO
)] and lithium chloride [LiC1]. However, it is not limited to the above-mentioned metal salts, and chlorides, sulfates, acetates, nitrates, and other salts other than the above-mentioned metal salts can also be used as long as they are salts made of the above-mentioned metal ions. can. Among the metal salts mentioned above, calcium chloride, which has deliquescent properties, exhibits particularly excellent moisture absorption and desorption properties.

Although it may be thought that as the mixing ratio of metal salt to water-soluble polymer increases, higher moisture absorption and release properties can be obtained, the solubility of metal salt in polyvinyl alcohol aqueous solution decreases, so metal ions High dispersion is not possible, metal ions come into contact with each other, and the hygroscopic effect of the metal ions is also reduced, which may conversely result in poor hygroscopicity at an early stage.

On the other hand, when the mixing ratio of the metal salt is low, the amount of metal ions itself is small, resulting in poor moisture absorption ability.

Therefore, an appropriate mixing ratio of metal salts exists depending on the type of metal salt. For example, when calcium chloride [CaC1zl is used as the metal salt and polyvinyl alcohol is dissolved in water as the water-soluble polymer to make a 10% aqueous solution, the mixing ratio of calcium chloride is 20 mol% or more based on the hydroxyl groups of the polyvinyl alcohol. is necessary,
More preferably, the amount is 40 mol% or more.

In addition, even if the mixing ratio of calcium chloride exceeds 100 mol%, the moisture absorption rate hardly changes.
There is no need to mix more than 40 mol% of calcium chloride.
It is appropriate to mix them in an amount of mol % to 100 mol %.

Further, although one type of metal salt may be used, two or more metal salts may be mixed.

Since a water-soluble polymer is used in the present invention, water can be used as a g medium, so there is less risk of toxicity, explosiveness, etc. in the drying process during the manufacturing process, and there are also advantages in that it is easy to handle.

As mentioned above, water-soluble polymers that can be used in the present invention include natural polymers, semi-synthetic polymers, synthetic polymers, and the like.

For example, natural polymers include starch, mannan, marine species, plant mucilage, microbial mucilage, and protein. Examples of semi-synthetic polymers include cellulose and starch. Examples of synthetic polymers include polyvinyl alcohol, sodium polyacrylate, polyethylene oxide, and polyvinylpyrrolidone.

Among these, polyvinyl alcohol and polyvinylpyrrolidone are preferably used because they have good compatibility with metal salts and poorly water-soluble polymers.

In addition, when polyvinyl alcohol is used, either completely saponified polyvinyl alcohol or partially saponified polyvinyl alcohol having a degree of saponification of 90 mol% or less may be used.

When partially saponified polyvinyl alcohol is used as the water-soluble polymer of the present invention, fluidity during moisture absorption can be suppressed. This fluidity-suppressing effect is thought to be due to the effects of hydroxyl groups and acetyl groups present in partially saponified polyvinyl alcohol. In other words, hydroxyl groups have a high affinity for water, so they tend to gather around metal salts that are hydrated and retain water.On the other hand, acetyl groups have a lower affinity for water than hydroxyl groups, so It is in a state where it does not exist much around the metal salt. Since the acetyl groups of the partially saponified polyvinyl alcohol are likely to be arranged on the outside in this way, it is thought that the fluidity during moisture absorption is suppressed.

In addition, when partially saponified polyvinyl alcohol is used to suppress fluidity, the saponification degree is 90 mol% or less, 7
It is preferably 0 mol% or more.

This is because if the saponification degree is 90 mol% or more, it will be insufficient to suppress fluidity during moisture absorption, and if the saponification degree is 70 mol% or less, it will be difficult to sufficiently dissolve the metal salt.

Furthermore, the degree of polymerization of polyvinyl alcohol does not particularly affect moisture absorption and release properties, and is therefore not particularly limited.

An example of a method for manufacturing a highly moisture-absorbing and desorbing material using a water-soluble polymer and a metal salt as described above is as follows.

■Select the water-soluble polymer and metal salt to be used.

■Dissolve the water-soluble polymer in water to create a 10% aqueous solution.

(2) Mix metal salts with this aqueous solution and stir at room temperature for 2 to 3 hours to obtain a viscous liquid.

By mixing an aqueous emulsion of a poorly water-soluble polymer into the highly moisture-absorbing and desorbing material obtained in this way and drying it,
Respiratory material 1 can be obtained.

This poorly water-soluble polymer is used for the morphological stability of the breathing material itself during use. If only a highly moisture-absorbing and desorbing material were to be attached to the casing 2, the adhesive strength of the water-soluble polymer would be used alone, so under high humidity conditions, the highly moisture-absorbing and desorbing material would swell and become unstable in shape. However, in the breathing material 1 obtained by mixing and stirring a poorly water-soluble polymer emulsion and an aqueous solution of a highly moisture-absorbing and highly moisture-absorbing material and then drying it as in the present invention, the highly moisture-absorbing and desorbing material is water Nf. Since it is fixed by @-type polymer, almost no morphological change occurs even under high humidity.

In addition, since the breathing material 1 of the present invention has many micropores as described above, it is presumed that moisture is absorbed through the micropores, and the hygroscopicity of the highly hygroscopic material itself is not hindered at all. do not have. Furthermore, in the breathing material 1 of the present invention, the highly hygroscopic material is surrounded by poorly water-soluble polymers that do not like moisture, so moisture quickly moves to the highly hygroscopic material and absorbs moisture more efficiently. can be done.

In the present invention, water is added to the viscous liquid of the highly moisture-absorbing and desorbing material. l
Unless the soluble polymer emulsion is mixed and uniformly dispersed, only the respiratory material 1 with uneven hygroscopicity can be obtained. Therefore, it is necessary to use a common solvent for both, but since water is used as the solvent for the highly moisture-absorbing and desorbing material, it is desirable to use an aqueous emulsion for the poorly water-soluble polymer.

Examples of such poorly water-soluble polymers include phenolic resin,
Epoxy resins, acrylic resins, vinyl resins, urea and melamine resins, polyester resins, styrene resins, silicone resins, polyethylene resins, polyamide resins, urethane resins, etc. can be used. However, the present invention is not limited to these poorly water-soluble polymers, as long as these poorly water-soluble polymers exist stably as an aqueous emulsion. Among these, it is preferable to use vinyl resin, and among these vinyl resins, it is most preferable to use vinyl chloride resin, which has a strong cohesive force.

The concentration of the aqueous emulsion is not particularly limited, but it is preferably such that the dry weight ratio of the poorly water-soluble polymer is 1 to 10 to 1 of the highly moisture-absorbing and desorbing material. This is because if the proportion of poorly water-soluble polymers is less than 1, the material will lack strength and shape stability even though poorly water-soluble polymers are used; This is because if the ratio of molecules exceeds 10, uniform dispersion of the highly moisture-absorbing and desorbing material and the poorly water-soluble polymer emulsion itself becomes impossible. Within this range, it is particularly preferable that the ratio of the poorly water-soluble polymer to 1 part of the highly moisture-absorbing and desorbing material is 2 to 6 parts.

As a method of installing the breathing material 1 in the housing 2, it is possible to directly apply the breathing material 1 in a viscous liquid state before drying to the housing 2, and then drying and installing the breathing material 1. The respiratory material 1 may be provided by disposing a binder in dots or the like. In the latter case, the respiratory material 1 may be in the form of a film obtained simply by drying, or may be obtained by impregnating a fibrous material or the like and then drying it. When it is impregnated into a female material, the poorly water-soluble polymer is coagulated and fixed at the intersections of the fibers, so it has excellent strength and the surface area of the breathing material 1 that can act is widened, so this is a preferred practice. It is a form. Note that the fibrous material is not particularly limited, and woven fabrics, knitted fabrics, nonwoven fabrics, etc. can be used.

In addition, in order to provide the respiratory material 1 in the housing 2, as shown in FIG.
As shown in the figure, by subjecting the breathing material itself to a pleat process, moisture can be absorbed and released from both sides of the breathing material 1, making it possible to prevent malfunctions more efficiently. In any of the above cases, it is more preferable to use the respiratory material 1 held in the MII-like material from the viewpoint of processability and shape retention.

Note that the spacer 3 may be of any type as long as the breathing material 1 is in close contact with the ceiling of the casing and does not impede moisture absorption and desorption on one side.For example, spacers 3 may be of any type, such as rectangular parallelepiped spacers provided at both ends of the ceiling of the casing 2. can do.

The housing 2 provided with such a breathing material 1 may be made of metal such as aluminum or iron, phenol resin, epoxy resin, acrylic resin, urea or melamine resin, polyester resin, styrene resin, silicon resin, polyethylene resin, or polyamide resin. The same materials as those conventionally used can be used, such as resins such as urethane resins, vinyl resins, or those resins that are plated to give conductivity.

Examples are illustrated below, but the invention is not limited to the following examples.

Example E] (Examples 1 to 2) After dissolving polyvinyl alcohol with a degree of saponification of 90% in water to make a 10% by weight aqueous solution, 60% by mole of calcium chloride was added to the hydroxyl group of this polyvinyl alcohol.
The mixture was mixed and stirred for 3 hours to obtain a colloidally dispersed highly moisture-absorbing and desorbing material.

Next, using an aqueous vinyl chloride resin emulsion at a temperature of 42% by weight, vinyl chloride resin and a highly moisture absorbing/releasing material were mixed at a dry weight ratio of 2:1, and stirred for 3 hours to form a uniformly dispersed sol. A solution was obtained.

This sol-like solution was impregnated into a nonwoven fabric made of flame-retardant polyester fibers with a basis weight of 50 g/Il' at a rate of 20 g/m'' (Example 1) or 10 g/m2 (Example 2), dried, and breathed. Material 1 was obtained.

As case 2, the length, width, and height are each 1281! +,
A rectangular parallelepiped box made of 210W1I and 40III aluminum was used, and a circuit as shown in FIG. 3 was installed on the inside bottom of the box.

100X 1g3 (i++s) of the breathing material 1 obtained as described above is placed on the internal ceiling of the casing 2 like S.
The size of the casing for electronic equipment of the present invention was obtained by adhering with double-sided tape.

(Comparative example) Same cable material and size as Examples 1 and 2, and Example 1 on the internal bottom surface.
A casing having a circuit similar to that in Example 2 to 2 was used, but the breathing material 1 was not adhered to the internal ceiling portion of the casing, so that a casing similar to the so-called conventional casing was obtained.

(Malfunction Prevention Test) The casings 2 of Examples 1 and 2 and the comparative example were left at 0° C. for 1 hour, and then placed in a constant temperature chamber at 50° C. and 80%. Then, as shown in FIG. 3, a voltage of 5 volts was applied to terminal A inside the housing, and the output voltage of terminal B was measured. In other words, resistance R
is not connected, so normally no voltage is applied to terminal B, but if condensation occurs, water becomes a medium and short circuits, current flows, and voltage is applied to terminal B. We decided to determine whether this would cause malfunctions.

As shown in Fig. 4, this measurement is based on the time T until reaching the maximum voltage value at that time, and the voltage rise time Tx.
, and the highest voltage H to estimate the dew condensation state.

Each of these measurements was performed three times, and the results are shown in Table 1.

As can be seen from these results, it can be seen that the electronic device casing of the present invention is excellent in that it does not malfunction even under such severe conditions.

(Margin below) Table 1゜ temperature, Voltage change due to humidity change ---: Indicates that there is no numerical change.

FS: Indicates full scale voltage.

[Effects of the Invention] The two bodies for electronic devices of the present invention include a breathing material containing a mixture of a highly moisture-absorbing and releasing material in which metal ions are included in a colloidal state in a water-soluble polymer and a poorly water-soluble polymer inside the housing. This prevents dew condensation and, as a result, prevents electronic equipment from malfunctioning.

In addition, by interposing a spacer between the breathing material and the inside of the body, or by applying pleat processing to the breathing material, it is possible to use both sides of the breathing material, which absorbs a large amount of moisture. Since the speed can be increased, superior moisture absorption and desorption properties can be exhibited, and malfunctions can be effectively prevented.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view of a housing having a spacer. FIG. 2 is a partially cutaway perspective view of the casing in which the breathing material is pleated. Figure 3 is a circuit diagram used in the malfunction prevention test. Figure 4 is a graph of the time T required to reach the maximum voltage value and the voltage rise time T2. 1・- 3・・ A, B・ T1・ Tt... H... Breathing material 2... Housing spacer terminal R... Time until the resistance reaches the maximum voltage value Voltage rise time Maximum voltage and Indicates maximum voltage H

Claims (3)

[Claims] (1) An electronic device characterized in that the inside of the casing is equipped with a breathing material 1 containing a mixture of a highly moisture-absorbing and desorbing material in which metal ions are included in a colloidal state in a water-soluble polymer and a poorly water-soluble polymer. housing. (2) The casing for electronic equipment according to claim 1, characterized in that a spacer 3 is interposed between the breathing material 1 and the casing 2. (3) The electronic device casing according to claim 1, wherein the breathing material 1 is pleated.