JPH0635364B2 - Sustained release insect repellent sheet - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an insect repellent to be put into a container for storing clothes, and more specifically, it releases an insect repellent gas of a concentration necessary and sufficient for insect repelling for a long period of time. The present invention relates to a controlled release insect repellent sheet.

[Prior art]

Insect repellents such as camphor, naphthalene, and parachlorobenzene are used for insect repellent of stored clothes. Since all of them are tablet type, they sublime from the surface. The sublimation rate depends on the vapor density of the atmosphere and also on the surface area of the tablet. Therefore, when the surface area of the initial stage is large, an unnecessarily large amount of insect repellent vapor is generated, and when the clothes are taken out and worn, a so-called naphthalene odor is contained,
It took a long time to remove it. On the other hand, since the insect repellent sublimes when it is stored for a long time, it is necessary to reinforce the insect repellent regularly.

In order to solve the above-mentioned drawbacks, conventionally, a method of reducing the sublimation rate by making a notch in one or two places of the tablet wrapping or wrapping with Japanese paper has been adopted.

However, it is difficult to properly adjust the sublimation rate by these methods, and it is troublesome to take out the unsublimated insect repellent remaining in the container.

[Problems to be solved by the invention]

There has been a demand for a sustained-release insect repellent that can maintain a substantially constant sublimation rate from the beginning when it is put into a clothing container and is easy to handle.

[Means for Solving Problems] and [Function] The present invention is an open-celled polymer porous sheet,
The inner layer portion side of the sheet having an asymmetric structure, in which the pore diameter of the outer layer portion of the sheet is significantly smaller than the pore diameter of the inner layer portion, the inner layer portion side of the insect repellent absorbing sheet obtained by absorbing the insect repellent, the insect repellent of other similar structure It is characterized in that it is attached so as to face the inner layer side of the agent-absorbing sheet, or is covered with a non-air-permeable coating.
That is, in order to control the sublimation rate of the insect repellent, a porous polymer sheet is used, and a sheet having an asymmetric structure in which the diameters of the bubbles are remarkably different between the one surface and the other surface is used. As the inner layer side, and by absorbing or sandwiching the insect repellent on the inner layer side, the insect repellent mainly absorbed on the inner layer side is slowly sublimated from the dense bubbles on the outer layer side, resulting in the sublimation rate. To adjust.

Hereinafter, the present invention will be described in detail.

Asymmetric sheets include polysulfone, polyacrylonitrile, polyvinyl alcohol, polyvinylidene fluoride,
It is an open-cell foam made of polyamide, polyimide, cellulose acetate or the like, and its pore size is remarkably different between the front surface portion and the back surface portion. That is, even though it is a thin sheet with a thickness of 0.1 mm to 1.0 mm, its pore size is about
About 100 to 10,000Å, about 10 to 100 μm on the back side, and 10 to 10,000 times the pore size, preferably 100 to 1000
It is about twice as different.

A sheet having such an asymmetric structure can be relatively easily manufactured by using a method such as a phase separation method. That is, when a water-soluble solvent solution of a polymer is cast on a substrate such as a glass plate so as to have a constant thickness and then immersed in a gelling bath such as water, small bubbles are generated on the substrate contact surface side,
Large bubbles are generated on the other side.

The insect repellent absorbent sheet is produced by applying a repellent insect repellent such as naphthalene, camphor, or balaclobenzene in a molten state to the substrate non-contact surface side of the above-mentioned asymmetric structure sheet, that is, the side having large bubbles. Since this surface side has a large pore size, it is possible to absorb and hold a large amount of these insect repellents. In addition, the applied insect repellent is integrated with the sheet and is easy to handle. On the other hand, on the substrate contact surface side of this sheet, that is, on the surface side having a small pore diameter, the amount of the insect repellent which can be sublimated through these small holes is limited, and the amount is proportional to the sheet area.

This insect repellent absorption sheet needs to cover the inner layer side so that the repellent does not sublime from the surface with a large pore size which is the inner layer, and is a non-breathable and oil resistant sheet of polysulfone, polyethylene, polypropylene, polyvinyl chloride, etc. May be attached. Also, two insect repellent absorbent sheets may be attached with their inner layer portions facing each other. In this case, the insect repellent slowly sublimes from both sides of the sheet.

The method for fixing the two insect repellent absorbent sheets to each other or the one insect repellent absorbent sheet and the non-breathable sheet is not particularly limited, but even if the heat-sealed portion is linearly provided at a constant interval. Good. If the linear heat-sealing part is provided in a vertical and horizontal lattice, the sheet is divided into small rectangular sections, and if the heat-sealing part is cut during use, the insect repellent is hardly exposed in the cross section of the sheet, and There is no danger that the insect repellent will sublime rapidly. The line-shaped fused portion does not necessarily need to have the parallel line groups orthogonal to each other.
The number and angle of parallel line groups such as parallel line groups in three different directions are arbitrary. Even if such a sheet is cut at an arbitrary portion, the insect repellent sublimates slowly from the remaining uncut section at a constant speed because the cross sections of the sections are sealed independently.

〔effect〕

According to the present invention, despite containing a large amount of insect repellent, the sublimation rate is slow and the insect repellent effect can be exerted for a long period of time. Furthermore, since it is in the form of a sheet, it can be easily cut, and if it is placed under a clothing container, it does not take up much space, and if the clothing is wrapped like a wrapping paper, it can be safely left as it is and is extremely convenient in handling.

〔Example〕

After mixing and dissolving 20 parts by weight of polysulfone (P-1700, a product of Nissan Chemical Industries, Ltd.) and 80 parts by weight of dimethylformamide (manufactured by Kanto Chemical Co., Ltd.), this solution was placed on a glass plate using a 0.3 mm spacer. It was cast. After leaving it for about 30 seconds, it was immersed in a gelling bath which was filled with tap water, and allowed to stand for 5 hours to obtain a porous polymer sheet having an asymmetric structure. After drying this sheet, naphthalene melted at 90 ° C. was applied to the surface having the larger pore size and cooled to solidify to obtain an insect repellent absorption sheet.

The two insect repellent absorbent sheets thus obtained were faced with their naphthalene-coated surfaces facing each other, and heat-sealed in the form of parallel lines that were perpendicular to each other as shown in FIG. Reference numeral 1 is an insect repellent absorbent sheet, 2 is an inner layer portion thereof, and 3 is an outer layer portion thereof. Reference numeral 4 is a naphthalene layer, and a large amount of naphthalene is absorbed and held in the inner layer portion. Reference numeral 5 is a heat-sealing portion arranged in a grid pattern. Bubbles are compressed by heat fusion, and almost no insect repellent is present in this portion.

When this gradual release insect repellent sheet was laid on a drawer of a Japanese dansu and the insect repellent effect was examined, it was found to be repellent for one year. In addition, when the same amount of tablet-type naphthalene was put into the drawer of the same Japanese dansu, it sublimated completely in 3 months, and the insect repellent effect was lost.

[Brief description of drawings]

FIG. 1 is an enlarged perspective view showing a cross section of one embodiment of the present invention. In the drawings, reference numeral 1 is an insect repellent absorbent sheet, 2 is an inner layer portion, 3 is an outer layer portion, 4 is a naphthalene layer, and 5 is a heat fusion portion.

Claims (2)

[Claims] 1. A porous porous polymer sheet having an open cell structure, wherein the outer layer portion of the sheet has an asymmetric structure in which the pore diameter is significantly smaller than that of the inner layer portion, and the insect repellent is absorbed on the inner layer portion side. The insecticide-absorbing sheet having the same structure as the insecticide-absorbing sheet having the same structure as the insecticide-absorbing sheet with the inner layer facing the inner layer is adhered to the sheet or is covered with a non-breathable film. Sheet. 2. An insect repellent absorbent sheet is attached so as to face the inner layer side of another insect repellent absorbent sheet having the same structure or is covered with a non-breathable coating to fuse the two sheets together. Arrange them so that the fused parts that are attached are parallel lines,
The sustained-release insect repellent sheet according to claim 1, wherein the set of parallel line-shaped fused portions is arranged in at least two directions.