JPH0511953B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a coating material suitable for drying brown leaf tobacco. In particular, by imparting moisture absorption and desorption properties to the coating material itself, it has the characteristic of preventing the rapid drying of dried leaf tobacco and the formation of stuffy and rotten leaves. (Prior Art) It has long been pointed out that leaf tobacco drying houses constructed of synthetic resin films have the problem of rapid drying of leaf tobacco. Various films with reduced light transmittance have been proposed in the past. For example, Japanese Patent Publication No. 49-16637 proposes an invention in which leaf tobacco is dried using a synthetic resin film having an average transmittance of 30 to 50%. However, in actual drying, rapid drying cannot be completely prevented due to a decrease in transmittance of this degree, and during the day on a sunny day, the room temperature is over 40℃ and the relative humidity is under 70%. Leaf tobacco will be exposed to these conditions. In order to further improve the high temperature and low humidity conditions even during sunny days, a further reduction in transmittance is required. There is a strong possibility that this will lead to the production of stuffy or rotten leaves under these conditions. Therefore, in order to prevent the formation of rapidly dry leaves, conventionally,
Dry control operations such as opening the hem of the greenhouse during the day to promote ventilation or removing and removing shielding curtains had to be carried out frequently. Furthermore, JP-A-61-100130 proposes an invention relating to a double-structured agricultural covering material having a synthetic resin film on the outside and an agricultural synthetic resin film coated with a water-absorbing resin on the inside. There is. The covering material of the invention is intended to be used as a roof structure for facility cultivation of plants, and one of its constituent requirements is to maintain visible light transmittance at 70% or more so as not to interfere with photosynthesis of plants. In the same bulletin,
There is no suggestion of any use for drying leaf tobacco, and its constituent features are clearly different from the coating material of the present invention. (Problems to be Solved by the Invention) The present invention solves the above-mentioned problems of the prior art, and significantly reduces the chance that leaf tobacco encounters high temperature and low humidity conditions during the daytime on sunny days without the need for frequent drying control operations. It is an object of the present invention to provide a coating material for drying brown leaf tobacco, which is suitable for reducing the production of stuffy leaves and rotten leaves. (Means for Solving the Problems) The present invention provides a brown film characterized by having a synthetic resin film as the outside, a water-absorbing resin attached to the inside, and a visible light transmittance of 10 to 50%. The gist of this article is a coating material for drying seed and leaf tobacco. The synthetic resins used to manufacture the synthetic resin film constituting the outside of the coating material of the present invention include:
For example, polyvinyl chloride, polyvinylidene chloride,
Examples include homopolymers such as ethylene-vinyl acetate copolymer, polyethylene, polypropylene, polyester, polyamide, polymethyl methacrylate, polycarbonate, etc., and copolymers containing monomers constituting these polymers. One or more resins may be used as a film forming material to form a single film or a composite film. Coloring agents such as carbon black, titanium white, aluminum foil powder, titanium yellow and others can be used to reduce the transmittance of light by kneading or coating the synthetic resin film of the present invention. Furthermore, in order to almost completely block the transmission of ultraviolet rays, UV absorbers such as salicylic acid esters, benzophenones, benzotriazoles, nickel complex salts, and cyanoacrylates, or pigments and dyes that have absorbers in the ultraviolet region are used. It is preferable to use one type or two or more types. By this,
The ability to prevent "white blurred leaves" can also be added to the coating material of the present invention. It goes without saying that the synthetic resin film of the present invention may contain other additives, such as plasticizers, antioxidants, light stabilizers, lubricants, etc., as necessary. Furthermore, the water absorbent resin used in the present invention is
It has a large amount of hydrophilic groups in the molecule, and has 30% of its own weight.
It is a polymer substance that has the property of absorbing up to 1000 times more water, retaining it, and releasing it depending on the conditions. Water-absorbing resins include starch-based, acrylic-based, DVA-based, CMC-based, etc., but starch-based resins, which have a slow absorption rate, are particularly suitable. The adhesive for attaching the water-absorbing resin to the inside of the synthetic resin film of the present invention may be acrylic resin, vinyl acetate, vinyl chloride, vinylidene chloride, polycarbonate, polyethylene, polypropylene, polyester, polyamide, or a copolymer thereof. or a blend thereof. Although it is possible to directly attach the water-absorbing resin to the inside of the synthetic resin film of the present invention using the above-mentioned adhesive, it is more preferable to first prepare a non-woven fabric in which the water-absorbing resin is mixed and supported on hydrophilic fibers, and then A water-absorbing resin can be attached by pasting it on the inside of a synthetic resin film. Such a method is not only advantageous in that the hydrophilic fiber itself has moisture absorbing and desorbing properties, but also in that it is possible to increase the upper limit of the amount of water absorbent resin that can be impregnated. Examples of the hydrophilic fibers used in this case include fibers such as pulp, polyvinyl alcohol, rayon, and acetate. Of course, this nonwoven fabric also serves to reduce the transmittance of visible light. (Function) A drying house is constructed by a conventional method using the coating material for drying brown leaf tobacco of the present invention, and leaf tobacco is dried in the sun in the house. A portion of the water that evaporates from the tobacco leaves suspended in the greenhouse is absorbed and retained by the water-absorbing resin of the coating material of the present invention, but the indoor temperature rises during the day, causing the leaves to dry out rapidly.
When trying to achieve high temperatures above ℃ and low humidity conditions of below 70% relative humidity, the moisture retained in the water-absorbing resin is released and prevents the relative humidity inside the greenhouse from falling below 70%. to play. This prevents rapid drying of leaves. The visible light transmittance of the coating material of the present invention is 10 to 50%.
More preferably, it is 20 to 30%, which has the effect of suppressing the high temperature and low humidity conditions during the day on sunny days to some extent. Even without opening the greenhouse, the relative humidity inside the greenhouse can almost never drop below 70%. Furthermore, when rain or cloudy weather continues for a long period of time, the moisture absorption effect of the water-absorbing synthetic resin can keep the humidity inside the greenhouse slightly low, which prevents stuffy and rotten leaves. Become. (Example) Next, an example of the coating material of the present invention and test results of leaf tobacco drying using the same example will be described. The structure and characteristics of the coating material according to one embodiment of the present invention are as follows. That is, as the outer synthetic resin, a 0.1 mm thick satin film made of polyvinyl chloride coated with aluminum foil powder is used, and its light transmittance is 40%. The inside of the synthetic resin film was made by mixing 10 g of Sumikagel N-100 (trade name) from Sumitomo Chemical Co., Ltd., a starch-based water-absorbing resin, with cotton-like pulp, which is a hydrophilic fiber, per 1 square meter. A nonwoven fabric with a thickness of 1.3 mm was attached using vinyl acetate/acrylic copolymer as an adhesive. The visible light transmittance when the nonwoven fabric was attached to the synthetic resin film was 20%. The water absorption characteristics of this coating material at a temperature of 35°C and a relative humidity of 98% are as shown in Figure 2.
The moisture release characteristics at 65% are shown in Figure 3. Using 62 square meters of the above-mentioned coating material of the present invention,
It formed the outer wall of a 22.5 square meter (5 m x 4.5 m, 2 m high) semicylindrical leaf tobacco drying house. Into this drying house, Burley tobacco that had been cut and harvested was subjected to a ``rough draining'' treatment before being hung. The lifting amount was 360Kg. As a control, the visible light transmittance of the above polyvinyl chloride film covered with an aluminum blackout curtain was 10%.
A drying house with the same structure as above was made using a conventional covering material exhibiting the following characteristics, and the same amount of the same leaf tobacco was suspended and dried. Leaf tobacco was hung on August 4, 1988, and thereafter drying was allowed to proceed without drying control operations such as opening the hem until the end of drying in both the invention plot and the control plot. Figure 1 shows the results of a survey of changes in relative humidity inside the drying house during the day on a sunny day 10 days after the start of drying (the progress of leaf tobacco drying is approximately 80% browning). As is clear from Figure 1, while the control area using conventional covering materials was exposed to low humidity conditions with a relative humidity of 70% or less for about 8 hours from before 9:00 to after 2:00 p.m.
In the present invention area, the relative humidity only reached 70% at 2:00 p.m. This shows that the coating material of the present invention is extremely effective in preventing rapid drying of leaves. Drying of the tobacco leaves was completed on August 24th, yielding 38.3 kg of dried leaves. The results of the quality investigation of the dry leaves are shown in Tables 1 and 2.

[Table]

[Table] As is clear from Tables 1 and 2, in the present invention plot, white blurred leaves,
There were no rapidly dry leaves, stuffy leaves, or rotten leaves, and the smoking taste evaluation results were 2 points better than the control group. (Effects) When a house for drying tobacco leaves is made using the coating material of the present invention and the tobacco leaves are dried, it is possible to prevent the production of leaves with deteriorated quality such as rapidly drying leaves. In order to prevent the production of leaves with deteriorated quality during the drying period, drying control operations such as hemming are not required at all or can be minimized, which is extremely labor-saving.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the change in relative humidity in a greenhouse during the day on a sunny day when leaf tobacco is dried using a coating material according to one embodiment of the present invention. FIG. 2 is a graph showing the same example as in FIG. 1. Covering material temperature 35℃ relative humidity 98
%, and FIG. 3 is a graph showing the moisture release characteristics at a temperature of 25° C. and a relative humidity of 65%.

Claims (1)

[Claims] 1. A synthetic resin film is used as the outside, a water-absorbing resin is attached to the inside, and the transmittance of visible light is 10 to 10.
50% coating material for drying brown leaf tobacco. 2. The covering material for drying brown leaf tobacco according to claim 1, wherein the water-absorbing resin is attached by attaching a nonwoven fabric in which a water-absorbing resin is mixed and supported on hydrophilic fibers.