JP2001315826A - Preserving method for volatile substance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a preserving method for a volatile substance wherein long preservation is possible while suppressing vaporization of components. SOLUTION: The method comprises steps of receiving the volatile substance in a hermetic container and keeping the inside of the container at a negative pressure for preservation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for preserving volatile substances, and more particularly to a method for preserving volatile substances which enables long-term storage while suppressing volatilization of volatile components.

[0002]

2. Description of the Related Art In general, a paint consists of a solution obtained by diluting a resin or oil as a coloring component with a solvent (thinner). When this paint is applied, the solvent volatilizes and the coloring component remains as a film. I have. For this reason, paint containers are commercially available with their lids hermetically sealed. However, once the paint container is opened, it is difficult to make the lid completely sealed, so that the solvent evaporates little by little from the gap formed by the lid, and the coloring component often gradually hardens.

[0003] Since the amount of the solvent decreases in this way, when the paint container once opened is reused, the solvent concentration is adjusted by adding the solvent each time before use. But,
When the period until reuse is long, regeneration may not be possible due to the addition of the solvent, and may eventually be discarded. Also, even when reusable, a large amount of solvent needs to be added, causing considerable waste.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and to provide a method for preserving a volatile substance which enables long-term preservation while suppressing volatilization of volatile components. .

[0005]

The method for storing volatile substances according to the present invention is characterized in that a volatile substance is stored in a sealed container, and the container is stored while being kept under a negative pressure. is there.

[0006] When the inside of the sealed container containing the volatile substance is brought into a negative pressure state, the negative pressure is considered to promote the volatilization of the volatile substance. However, according to the results of many experiments performed by the present inventors, when the inside of the sealed container containing the volatile substance is kept under a negative pressure, the tendency of the volatile substance to volatilize under atmospheric pressure (normal pressure). It has been found that it can be suppressed more than the case where it is performed. As a result, volatile substances can be stored for a long period of time, and the intermediate use amount of the solvent can be reduced, thereby contributing to resource conservation.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a volatile substance
A mixture of a mixture of a volatile substance and a non-volatile substance, as well as a volatile substance alone (mixed liquid)
It is a generic term that also includes

[0008] Volatile substances are liquids having a high vapor pressure and a low boiling point at room temperature. Organic solvents such as thinners are applicable, and examples thereof include ethyl ether, ethyl alcohol, ethyl acetate, benzene, hexane, and industrial gasoline. In addition, examples of the inorganic substance include liquid ammonia and liquid sulfur dioxide.

[0009] Examples of the mixture containing a volatile substance include coating materials such as paints, printing inks and rust inhibitors; cosmetics such as shampoos, fragrances and creams; oils and fats such as industrial oils and liquid fuels; And the like.

The method for storing volatile substances according to the present invention is characterized in that a sealed container is used, the volatile substance is stored in the sealed container, and storage is performed while maintaining the inside of the container at a negative pressure. As the pressure in the negative pressure state, the atmospheric pressure (about 0.
The state is not particularly limited as long as it is lower than 1 MPa), but is preferably 0.09 MPa or less, more preferably 0.07 MPa or less. By maintaining such a negative pressure, it is possible to suppress the volatilization of volatile substances and enable long-term storage, as is apparent from the examples described later.

Although the sealed container used in the storage method of the present invention is not particularly limited, a sealed container using a non-permeable sheet as a one-way valve as described below is preferably used.

That is, a small opening through which gas passes inward and outward is provided in a container body having a sealed structure, and a non-breathable sheet is covered on the outside of the opening. The sheet functions as a one-way valve and has at least one vent hole at a position offset from the opening. When the suction port of the suction device is applied to the outside of the sheet and sucked, gas (air) inside the container is released. The air is exhausted from the opening through the vent, and the inside of the container is sealed under a negative pressure. When the sheet is in the sealed state, the sheet closely adheres to the periphery of the opening, and a portion corresponding to the opening is curved and deformed toward the inside of the container. The above-mentioned sheet is designed to function as a one-way valve for preventing gas movement from the outside to the inside of the container. By using a familiar tool such as a manual or powered vacuum pump as a suction tool, it is extremely simple. It can be used as a simple sealed container.

The size of the container is not particularly limited, and may be any size from small for home use to large for business use. As the material of the container, any of metal, glass, plastic and the like can be used. Among them, stainless steel having excellent chemical resistance and impact resistance is preferable because of its wide versatility.

The opening is provided on the lid or the upper surface of the container body. The size of the opening only needs to be such that when the outside is covered with a non-breathable sheet, the suction is held by the internal negative pressure. The shape of the opening is not particularly limited, and may be a polygon such as an ellipse, a triangle, or a square, a star, a slit, or the like, and among them, a circle is preferable.

The number of openings may be one or more. In the case of one, the productivity of the container body and the lid is good, and in the case of providing a plurality, the sheets act to pull each other between the adjacent openings, so that the sheet holding and holding property is improved. Can be. When a plurality of openings are provided, their sizes and shapes may be the same or different.

The size of the opening is preferably such that the maximum distance (diameter in the case of a circle) across the opening is 3 mm to 15 mm. If the maximum distance is smaller than 3 mm, the curved deformation of the sheet becomes small, so that visual confirmation becomes difficult. Of course, such a small opening does not lead to the bending deformation of the sheet, but generates an attraction force, so that it can be used as an auxiliary together with the opening that allows the sheet to be bent.

Although the maximum distance may be larger than 15 mm, the required area of the sheet becomes excessively large, which is uneconomical in terms of cost. In addition, as a result of the sheet becoming too large, the suction tool becomes large and becomes difficult to handle. Also, as a result of the sheet becoming too large, wrinkles and the like are generated at the close contact portion, and the sheet is strongly pulled toward the opening, so that the end part is lifted up and peels off, or comes off in contact with other things during transport of the container. Accidents such as

It is preferable to form an inwardly concave portion on the surface of the lid or the container body provided with the opening. By forming the concave portion and storing and holding the sheet in the concave portion in this manner, it is possible to improve the suction holding property of the sheet.

The sheet used in the present invention is made of a non-breathable and flexible material as a part for sealing the opening. In addition, since the flat state and the curved state are alternately repeated, an elastic material having excellent elastic recovery is used as the material.

Examples of such an elastic material include silicone rubber, thermoplastic polymer elastomer, synthetic rubber and natural rubber, among which silicone rubber is particularly preferred. Examples of the thermoplastic polymer elastomer include a polyamide elastomer, a polyurethane elastomer, a polyester elastomer, a polyolefin elastomer, and a styrene block elastomer.

The shape of the sheet is not particularly limited as long as it covers the opening on the container side. For example, a circular shape, an elliptical shape, a polygonal shape and the like can be adopted, and a circular shape is particularly preferable.
The area of the sheet must be larger than the opening so that the entire opening can be covered. When a plurality of openings are provided on the container side, the openings have an area that covers all of the openings at the same time.

This sheet is provided with a vent hole at a position offset from a portion corresponding to the opening. As will be described later, this vent hole is used as a means for exhausting the gas inside the container when performing an operation of adsorbing and holding the sheet in the container. The shape and size of the ventilation hole are not particularly limited, but the shape is preferably circular, and the size may be sufficiently smaller than the opening. For example, 0.3-2.0 m in diameter
m. Further, the thickness is preferably about 0.5 to 3 mm.

The mating surface where the upper surface of the lid or the upper surface of the container body and the sheet are in close contact with each other is preferably mirror-finished in order to improve the tight sealing property. More specifically, it is preferable that the upper surface of the lid, the upper surface of the container body, and the sheet are mirror surfaces having a surface roughness of 0.2S or less on the respective mating surfaces.

The edge of the opening may be formed into a curved surface at least by deburring or chamfering so that the sheet can be smoothly deformed without being damaged when the sheet is curved and deformed.

In the present invention, as a method of using the above-mentioned sheet to put the inside of the container body into a negative pressure state (a reduced pressure state), first, the outside of the opening provided in the container body or the lid is covered with the sheet. The suction port of the suction tool may be brought into contact with the outer surface of the sheet so that the opening and the ventilation hole of the sheet are located inside the suction port, and suction may be performed in that state. By the suction operation of the suction tool, the sheet is swelled inside the intake port, and the air in the container is sucked out from the opening through the sheet ventilation hole to the outside, so that the inside of the container can be brought into a negative pressure state. it can. When the suction operation is stopped, the sheet comes into close contact with the lid or the outer surface of the container main body, and a portion corresponding to the opening is bent inward, and the container is sealed.

By maintaining the inside of the container in a negative pressure state as described above, volatilization of the volatile substance contained in the container is suppressed, and long-term storage can be performed.

FIGS. 1A and 1B show an example of a storage container used in the present invention, in which FIG. 1A is a longitudinal sectional view before the inside is brought into a negative pressure state, and FIG. It is a longitudinal cross-sectional view when is made into a negative pressure state.

The container main body 2 of the storage container 1 is made of stainless steel or glass, and has a closed structure in which a lid 3 is detachably screwed into an upper inlet 10. A packing 4 is inserted between the lid 3 and the upper edge surface of the inlet 10 to seal the inside of the container. An opening 5 penetrating vertically is provided at the center of the lid 3, and a non-breathable sheet 6 is placed on the upper surface so as to close the opening 5. When a negative pressure is applied to the inside of the container, as shown in FIG.
And a portion corresponding to the opening 5 is curved and deformed inward to be held by suction. The sheet 6 is provided with four to eight air holes 7 at positions offset from the openings 5. This vent hole 7 is used as an exhaust passage when the inside of the container body 2 is depressurized, as described later.

The operation of bringing the inside of the container 1 into a negative pressure state can be performed as shown in FIGS. 2 (A) and 2 (B).

First, a non-breathable and flexible sheet 6 is placed on the upper surface of the lid 3 so as to cover the opening 5 and the ventilation hole 7 is offset from the opening 5. Next, the suction port Km of the suction tool K is pressed against the outer surface of the sheet 6. At this time, the opening 5 and the ventilation hole 7 both have the intake port Km.
Set so that it is inside.

Next, when suction is performed by the suction tool K, FIG.
As shown in (A), the sheet 6 is bent and deformed so as to float to the suction side, and the air inside the container is sucked out from the opening 5 through the ventilation hole 7 as shown by the arrow, so that the inside of the container is under negative pressure. The pressure is reduced.

When the suction operation is stopped, since the inside of the container is at a negative pressure, the sheet 6 is pulled back to the container body 2 side, as shown in FIG. The portion corresponding to 5 is concavely curved and deformed toward the inside of the container body 2.

When the sheet 6 is placed on the upper surface of the lid 3 as described above, the lid 3 may be provided with a plurality of openings 5 and, as in the embodiment of FIG. The sheet 6 may be formed in the concave portion 13 and housed in the concave portion 13. When the sheet 6 is stored in the concave portion 13 as described above, the sheet 6 is held on the upper surface of the container even after the decompression of the container main body 2 is released, and can be prevented from peeling off.

When the inside of the liquid storage container 1 is sealed in a negative pressure state as described above, the sheet 6 is sucked and held in the opening 5 of the lid 3 so as to bend and deform into the inside. It is maintained until the pressure is released. Since the hermeticity is maintained in this manner, the volatile substances contained therein are suppressed from volatilizing volatile components, and the initial quality is maintained for a long time.

[0035]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Each of the storage containers has the structure shown in FIG. 1, the container body is a transparent glass bottle, the lid has an opening, the sheet is 1.5 mm thick, and the surface roughness is 0.2 S. (Container of the present invention) and a normal container (conventional container) in which the container body is the same transparent glass bottle but the lid is not provided with an opening.

Into these two types of storage containers, the same amount of paint using a thinner as a solvent was placed in the same amount, and each was closed. The conventional container is kept at the atmospheric pressure (about 0.1 MPa), but the container of the present invention uses a suction tool to reduce the internal gas pressure to about 0.09 MPa and maintain the negative pressure state. Then, a storage test was performed for each.

(A1) to (A3) in FIG. 4 show the progress of the storage test using the container of the present invention.
1) to (B3) show the progress of a storage test using a conventional container. In this process, (A1) and (B1)
(A2), (B2) immediately after the paint is enclosed.
Is the state 20 days after the encapsulation, (A3), (B3)
Indicates a state after elapse of 6 months from the encapsulation.

In FIG. 4 showing the progress, S is a vacuum layer, Z is a normal pressure air layer, M is a liquid surface of the paint, Y is a solvent layer, G is a coloring component layer, and P is a coloring component and a solvent. And K indicates the boundary between the solvent layer and the mixed layer.

At the time when 20 days have passed since the coating of the paint, as shown in FIGS. 4 (A2) and 4 (B2), the liquid level M of the paint is lower in the conventional container than in the container of the present invention, and the amount of the solvent is reduced. More. The mixed layer P is thicker in the conventional container than in the container of the present invention. Further, in the container of the present invention, the mixed layer P is small, and the solvent layer Y and the coloring component layer G are quite clearly separated.

When six months have passed since the paint was filled,
As shown in FIGS. 4 (A3) and (B3), in the container of the present invention, the state substantially the same as the state of (A2) is maintained, and the solvent layer Y
Is not reduced, and is maintained at almost the same level, but in the conventional container, the solvent layer Y and the mixed layer P almost disappear,
Only the coloring component layer G is provided. That is, the volatile substance (solvent) was almost volatilized and disappeared, and many small cracks were observed on the surface M.

The paint of (A3) was stirred (A
It was restored to the state of 1) and could be used as a paint without any problem.

[Brief description of the drawings]

FIG. 1 shows a storage container used in the present invention, wherein (A) is a longitudinal sectional view before the inside of the container is made into a negative pressure state, and (B) is a longitudinal sectional view after the inside of the container is made into a negative pressure state. It is.

FIGS. 2A and 2B are explanatory views when the container in FIG. 1 is depressurized, and FIG. 2A is a longitudinal sectional view of a sheet portion during a suction operation;
(B) is a longitudinal sectional view of the same sheet portion after the suction operation.

FIG. 3 is a longitudinal sectional view of a storage container according to another embodiment used in the present invention.

FIG. 4 is an explanatory diagram of a storage test of the container of the present invention and a conventional container, wherein (A1) to (A3) are explanatory diagrams of the progress of the container of the present invention;
(B1)-(B3) are explanatory diagrams showing the progress of a conventional container.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Storage container 2 Container main body 3 Lid 5 Opening 6 Sheet 7 Vent hole 10 Inlet K Suction tool Km Suction port

Continued on front page F-term (reference) 3E067 AB81 AB96 BB08A BB11A BB14A CA16 EE56 FB11 GD06 3E084 AA04 AA12 AA22 AA24 AA32 AB05 AB06 CA01 CC03 CC08 DA01 DB12 FA09 FB01 GA01 GB01 HA03 HD01 KA04

Claims (4)

[Claims] 1. A method for storing a volatile substance in which a volatile substance is stored in a sealed container, and the inside of the container is maintained while maintaining a negative pressure. 2. A negative pressure state is provided in the sealed container by providing a one-way valve for preventing gas from moving from outside to inside of the container, and exhausting gas inside the container via the one-way valve. 2. The method for preserving a volatile substance according to 1. 3. The method for preserving a volatile substance according to claim 1, wherein the negative pressure inside the container is set to 0.09 MPa or less. 4. The method according to claim 1, wherein said volatile substance is a paint.
4. The method for preserving a volatile substance according to 2 or 3.