JP2001025347A - Covering sheet for fumigating sterilization and fumigating sterilization by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a covering sheet for fumigating sterilization, not polluting an environment, excellent in strength, having a barrier property against a fumigating gas and useful for removing pine weevils by laminating a biodegradable thermoplastic resin layer on the surface of a base paper consisting of a cellulosic component. SOLUTION: This covering sheet is obtained by laminating a biodegradable thermoplastic resin layer such as a polylactic acid on at least one side surface of a base paper (of which unit weight is preferably 50-70 g/m2) consisting of a cellulosic component. Further, the covering sheet is obtained by laminating the biodegradable thermoplastic resin layer on the one side surface of the base paper consisting of the cellulosic component and having >=300 sec/100 ml degree of ventilation or laminating the biodegradable thermoplastic polymer on both sides of the base paper having >=130 sec/100 ml degree of ventilation. Also, it is preferable to sterilize withered and damaged woods or soil with a fumigating agent and covering the treated withered and damaged woods or soil damaged by the insects with the covering sheet for fumigating sterilization.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fumigating disinfection coating sheet used for preventing fumigation agents from volatilizing when fumigating dead trees caused by pest damage or fumigation of soil. It relates to the fumigation method used.

[0002]

2. Description of the Related Art In recent years, damage to pine forests caused by pine worms has spread throughout the country except Hokkaido and Aomori Prefecture, and although the amount of damage has been halved from the peak, it is still at a level close to 1 million cubic meters every year. The extraordinary damage has not yet ended. Various measures have been taken to control the damage of pine worms, but fumigation treatment of damaged dead trees is one of the important factors, because it can eliminate pine wood beetles parasitic on dead trees, which will become the source of infection in the next fiscal year. It is a means. Concretely, carbum or carbum sodium salt is cut into pieces, processed into damaged logs, covered with a polyethylene sheet or a vinyl sheet, and sterilized by fumigation.

In addition, pests that inhabit the soil and cause great damage by infesting the crops cultivated there are known, and continuous cropping that accompanies the advanced use of farmland, such as localization of agricultural products and the spread of facility horticulture, involves the following: Increase the density and activity of soil pests,
The damage is increasing and becoming more chronic. Due to the special environment of being in the soil, there are few general pesticides that effectively act on the control of these soil pests, and soil disinfection with fumigants is performed as the most effective means. For example, fumigants such as methyl bromide, chloropicrin, carbam, dazomet, methyl isothiocyanate, and 1,3-dichloropropene exhibit a wide range of precise control effects. When using these soil fumigants, the soil surface is often covered with a sheet after chemical treatment in order to enhance the disinfecting effect.

[0004] As a sheet used as a coating material in the above-mentioned fumigation treatment, a plastic film such as polyethylene or polyvinyl chloride is used. Further, in order to further suppress the permeation and volatilization of the drug component from these sheets and films, improvements such as using a material having a high gas barrier property, making the sheet thicker, or forming a laminated structure have been proposed. . For example, JP-A-56-96648, JP-A-59-216534 and JP-A-8-3
No. 25108 discloses polyethylene / polyamide 6
Laminated films, polyvinylidene chloride / polyethylene, polypropylene laminated films and the like have been proposed.

[0005] However, these plastic sheets need to be collected from forests and agricultural lands and discarded after use. Not only does this collection and disposal take a great deal of labor and money, but it also causes various environmental pollution depending on the disposal method. In other words, when burying plastic sheets in soil, it causes the ground to soften in the buried site, and when incineration is performed due to lack of burial sites, high heat during combustion may cause damage to the incinerator, dioxin, etc. Releases harmful substances.

A method of using biodegradable plastic as a material for a plastic sheet for fumigation treatment and burying it in soil after use to decompose microorganisms is promising as a waste treatment method, but biodegradable plastic is extremely expensive. However, biodegradable fumigation disinfecting coating sheets have not been put to practical use because of the economical reason that this is the case and the physical property that the drug component is easily permeated.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a fumigation disinfection coating sheet having biodegradability and a high barrier property against fumigation gas, and a fumigation disinfection method which does not require disposal of the coating sheet. It is to provide.

A biodegradable thermoplastic resin film has a lower gas barrier property against a fumigant than a polyethylene film conventionally used in this field, and cannot be used as a covering sheet for fumigation disinfection. However,
According to the findings of the present inventors, a laminated paper obtained by laminating a biodegradable thermoplastic resin with a paper made of cellulose has excellent strength even with a small amount of the biodegradable thermoplastic resin used, and is resistant to fumigation gas. Has barrier properties. The present invention provides a fumigation disinfection coating sheet and a fumigation method using the same based on this discovery.

[0009]

SUMMARY OF THE INVENTION The present invention relates to a fumigation disinfecting covering sheet comprising a base paper comprising a cellulose component and a biodegradable thermoplastic resin layer laminated on at least one surface.

[0010] The present invention also provides a fumigation disinfecting coating comprising a base paper comprising a cellulose component and having an air permeability of 300 seconds / 100 ml or more, and a biodegradable thermoplastic resin layer laminated on one surface of the base paper. Regarding the sheet.

Further, the present invention is characterized in that a biodegradable thermoplastic resin layer is laminated on both sides of a base paper comprising a cellulose component and having an air permeability of 130 seconds / 100 ml or more, for fumigation disinfection. It relates to a covering sheet.

[0012] The present invention also relates to a method for fumigating disinfected dead trees, wherein the dead trees are treated with a fumigant and covered with the above-mentioned fumigation disinfecting coating sheet.

Further, the present invention relates to a method for fumigating and disinfecting soil, wherein the soil treated with a fumigant is covered with the above-mentioned fumigation disinfecting covering sheet.

The paper used as the base paper in the present invention is a paper made of a cellulose component, such as softwood pulp,
Wood pulp such as hardwood pulp, flax, kenaf, bagasse,
Non-wood pulp produced from non-wood plants such as Manila hemp is used as a raw material to make paper. Paper is made by entangled and stuck together various fibers,
In the present invention, since the base paper itself must also have biodegradability, synthetic paper made of synthetic polymer fibers having no biodegradability is incompatible.

[0015] Basis weight ^{15g / m 2 ~150g / m 2} , preferably ^{40g / m 2 ~80g / m 2} , more preferably 50
a ^{g / m 2 ~70g / m 2} . When the basis weight is less than 15 g / m ² , the strength and the effect of preventing fumigant volatilization are low even when laminated with a biodegradable thermoplastic resin, and when the basis weight exceeds 150 g / m ² , the biodegradable thermoplastic resin is used. The laminated sheet has insufficient flexibility, and a gap is generated between the ground surface and the dead tree, so that the sheet cannot be completely covered.

According to experiments, the higher the air permeability of the base paper, the more desirable it is for the laminated sheet of the base paper and the biodegradable thermoplastic resin to have a higher gas barrier property against the fumigant. In order to have gas barrier properties against fumigants equal to or higher than the polyethylene film used conventionally,
In the case of a laminated paper in which a biodegradable thermoplastic resin layer is laminated on one side of the base paper, the air permeability of the base paper is set to 300 seconds / 100.
ml or more, and in the case of a laminated paper having a biodegradable thermoplastic resin layer laminated on both sides of the base paper,
It is desirable that the air permeability of the base paper is 130 seconds / 100 ml or more. In order to obtain a higher fumigation gas barrier property, the air permeability of the base paper is 1000 seconds / 100 in each case.
Desirably, it is not less than ml.

As a method for increasing the air permeability of the base paper, there are a method of increasing the degree of beating of pulp as a raw material, a method of applying a coating agent to a paper web after paper making, and a method of performing a calendar treatment.
However, the improvement of the air permeability by the coating of the coating agent or the calendar treatment is excessive, and the adhesiveness becomes poor in the lamination with the biodegradable thermoplastic resin layer. It must be so small that it does not easily come off.

On the other hand, when a papermaking filler is added to the paper stock, the air permeability of the paper after the papermaking is reduced. However, the addition of the papermaking filler increases the water dispersibility of the paper or increases the opacity. This is desirable for improving the biodegradability of the product sheet, and may be required for the appearance of the product. Accordingly, in a combination of general papermaking techniques such as the degree of beating of the pulp, the addition of a filler for papermaking to the paper stock, and the application to a paper web after the papermaking, an appropriate air permeability of at least a predetermined value is obtained. It needs to be adjusted.

Examples of the filler for papermaking to be added to the paper stock include water-insoluble mineral powders such as calcium carbonate, clay and titanium oxide. Examples of the coating agent include a biodegradable polymer aqueous solution such as polyvinyl alcohol, carboxymethyl cellulose salt, alginate, starch, and a water-soluble cellulose derivative, and a pigment coating obtained by adding an inorganic filler to the polymer aqueous solution. Liquid and the like. Further, in order to increase the water resistance of the base paper, a sizing agent, a water repellent, and a wet strength imparting agent can be added as necessary. Examples of the sizing agent include rosin type, neutral rosin type, petroleum resin type, alkyl ketene dimer, alkenyl succinic anhydride type and the like. As the water repellent, a wax-based emulsion or a paraffin-based emulsion having biodegradability can be suitably used. Examples of the wet strength imparting agent include polyamine epichlorohydrin resin and polyamide polyamine epichlorohydrin resin.

The base paper thus obtained is laminated and compounded with a biodegradable thermoplastic resin on one or both sides to produce a laminated paper.

In the present invention, the biodegradable thermoplastic resin used for laminating on the base paper has both biodegradability and thermoplasticity, and is formed by injection molding, hollow molding, extrusion molding, or the like.
It is a resin that can be foamed and thermoformed. Representative examples of the biodegradable thermoplastic resin include an aliphatic polyester which is a polycondensate of glycol and a polyfunctional carboxylic acid. For example, polyethylene oxalate, polyethylene succinate, polyethylene adipate, polyethylene azelate, polybutylene oxalate, polybutylene succinate, polybutylene adipate, polybutylene sebacate, polyhexamethylene sebacate, polyneopentyl oxalate, and Copolymers such as polybutylene succinate adipate are included.

Further, a polymer comprising poly (α-hydroxy acid) such as polyglycolic acid and polylactic acid, and a copolymer thereof, poly (ε-caprolactone), poly (β
-Propiolactone) and copolymers thereof comprising poly ([omega] -hydroxyalkanoate) and copolymers thereof.

Further, poly-3-hydroxypropionate, poly-3-hydroxybutyrate, poly-3-hydroxycaprolate, poly-3-hydroxyheptanoate, poly-3-hydroxyoctanoate and the like And poly-3- (hydroxyalkanoate) such as a copolymer of poly (3-hydroxyvalerate and poly-4-hydroxybutyrate).

These biodegradable thermoplastic resins are supplied in the form of powder, pellet, sheet, or fiber.

The biodegradable thermoplastic resin is laminated and composited on the base paper using a melt-extruded laminator. The biodegradable thermoplastic resin is extruded from the slit in a molten state and laminated on the base paper before solidification. It can be carried out by a general laminating method of performing pressure bonding. The thickness of the biodegradable thermoplastic resin film layer can be adjusted by the discharge speed of the molten resin, the paper passing speed of the base paper, the slit width of the T die, and the like.

Further, a film produced from a biodegradable thermoplastic resin by a blow molding method or the like is laminated on a base paper, and the film is passed through a hot roll heated to a temperature near the melting point of the biodegradable thermoplastic resin. Laminated paper can also be manufactured by a method of melt-compression bonding. Furthermore, a solution prepared by dissolving a biodegradable polymer such as polycaprolactone in a solvent such as toluene is applied to a base paper, and a film manufactured from a biodegradable thermoplastic resin by a blow molding method or the like is bonded and dried. Laminated paper can be manufactured.

The laminated paper has a configuration in which a biodegradable thermoplastic resin film layer is provided on one side of a base paper, a configuration in which a biodegradable thermoplastic resin film layer is provided on both sides of a base paper, and a biodegradable thermoplastic resin film. The base paper may be disposed on both sides of the layer, and the base paper and the biodegradable thermoplastic resin film layer may each have a multilayer structure in which one or more layers are stacked. Further, each of the above-described configurations is a net in which biodegradable thermoplastic resin fibers are woven into a net shape, and a net in which biodegradable thermoplastic resin fibers or biodegradable thermoplastic resin films are heat-sealed at their entangled points at right angles to each other. The sheet may be joined to one or both sides of the sheet by the method of manufacturing a laminated paper using a hot roll or an adhesive to reinforce the strength.

The thickness of the biodegradable thermoplastic resin film layer is 10 to 50 μm, preferably 20 to 40 μm. When the thickness is less than 10 μm, the strength and gas barrier properties are insufficient even when laminated with paper, and when the thickness is more than 50 μm, there is almost no further improvement in gas barrier properties. It is economically disadvantageous to use a large amount of the plastic resin.

According to the experiment, only a cellulose-based paper used as a base paper or a film made of a biodegradable thermoplastic resin alone has a low gas barrier property against a fumigant. Gas barrier property against fumigants is improved, and air permeability of base paper is especially 10
When it is more than 00 seconds / 100 ml, the gas barrier property against the fumigant is remarkably improved. Although the reason for this has not been elucidated exactly, it is assumed that gas permeation is suppressed at the interface between the cellulose-based base paper and the biodegradable thermoplastic resin layer.

The above-mentioned laminated paper according to the present invention is formed into a sheet having an appropriate size for use, and is used for a fumigation disinfection coating for covering soil and dead wood. Specifically, after spraying a fumigant solution on soil or dead wood, cover with a covering sheet, bury the end of the sheet in the soil to create a closed space,
The inside is filled with a fumigant, and left for, for example, two to three weeks. The covering sheet prevents the fumigant from volatilizing to the outside, and provides a fumigating and disinfecting effect.

In order to further delay the biodegradation during the fumigation period, addition of a sizing agent, a water repellent, and a wet strength imparting agent to the base paper and an increase in the thickness of the biodegradable thermoplastic resin film layer result in the biodegradation. This can be achieved by suppressing the decomposability.

The covering sheet for fumigation disinfection according to the present invention comprises:
After the end of the fumigation period, it can be buried in soil and disposed of by biodegradation. The rate of biodegradation greatly varies depending on the form of burial in soil and weather, but the sheet collapses in about 6 months.

[0033]

EXAMPLES Hereinafter, the present invention will be specifically described based on examples and comparative examples, but the present invention is not limited to these. In addition, the characteristic value of each sheet in the example and the comparative example was measured by the following method.

(1) Basis weight: Measured according to JIS P8124.

(2) Thickness: Measured according to JIS P8118.

(3) Air permeability: JAPAN TAPPI
No. According to 5, the measurement was carried out with an Oken-type air permeability meter.

(4) Smoothness: JAPAN TAPPI
No. According to No. 5, measurement was carried out with an Oken type smoothness meter.

(5) Laminated film adhesive strength: A test piece having a length of 180 mm and a width of 15 mm was cut out in the extrusion direction of the laminated film, and the film layer and the paper layer were peeled off from the end of the length method to 50 mm. Peeling off both ends at constant speed elongation type tensile strength tester (Toyo Baldwin Co., Ltd.)
(Tensilon UTM-4-100 type), and peeled off 100 mm at a tensile speed of 30 mm / min according to JIS P8113, and the maximum strength during the peeling was measured.

(6) Tensile strength: Measured according to JIS P8113.

(7) Elongation: Measured according to JIS P8132.

(8) Wet tensile strength: JIS P8135
It measured according to.

(9) Fumigation Gas Barrier Property Test Using the test apparatus shown in FIG. 1, a barrier property test was performed on each sheet for chloropicrin and methyl isothiocyanate, which is an active ingredient of the barcam agent. In the apparatus shown in FIG. 1, a charging tank 1 and a permeating tank 2 are connected via a mold 5 at a portion of a communication hole 3 and a communication hole 4.
9.6 liters, there is an upper cock 6, a lower cock 7 and a ceiling cock 8, and the permeation tank 1 has an inner volume of 13.7 liters, and the upper cock 9, the lower cock 10 and the ceiling cock 11
There is. A packing 12, a space between the communication hole 3 of the charging tank 1 and the mold 5, and a space between the communication hole 4 of the permeation tank 2 and the mold 5, respectively.
13, the test sheet 14 was attached between the communication hole 3 of the charging tank 1 and the packing 12, and the medicine was dispensed into the charging tank 1.

The sample was stored in a constant temperature room at 25 ° C., and after a certain period of time, the gas concentration in the charging tank and the gas concentration in the permeable layer were measured. When using methyl isothiocyanate as a drug, methyl isothiocyanate was put in a petri dish, placed in a charging tank, and then assembled. After a lapse of 24 hours, the concentration was measured by collecting 0.3 ml of internal gas from the upper cock and the lower cock of each tank, and using a gas chromatograph equipped with an FID detector. When chlorpicrin is used as a drug, after assembling the apparatus shown in FIG. 1,
From the ceiling cock 8 of the charging tank 1, 5 ml of chlorpicrin was injected with a syringe. After 24 hours, 0.3 ml of the internal gas was collected from the upper cock and the lower cock of each tank, and using a gas chromatograph equipped with a TCD detector. A concentration measurement was performed.

The fumigant gas permeability was determined by the following equation. Fumigant gas permeability (%) = Permeation tank gas concentration (g / c)
m ³ ) ÷ Gas concentration in charging tank (g / cm ³ ) × 100

Example 1 Softwood bleached wood pulp 60 weights
Amount of hardwood bleached wood pulp 40% by weight slowness 65
° SR, and the basis weight was 34 g /
m²Paper was made so that During papermaking, coating amount 1 g / m
²Polyvinyl alcohol (Kuraray Co., Ltd.)
3% by weight aqueous solution of trade name PVA117H)
To produce base paper. Super Karen on this base paper
Dough processing, basis weight 35g / m ^TwoLaminating base for
Paper was manufactured.

Next, using a melt extrusion laminator (manufactured by Musashino Machinery Co., Ltd.), polybutylene succinate (Bionore # 1903, manufactured by Showa Kogaku KK), which is a biodegradable thermoplastic resin, was melted. At a die temperature of 260 ° C., a film having a thickness of 40 μm is laminated on one side of the base paper,
Single-sided laminated paper was manufactured.

Table 1 shows the physical properties of the base paper and the single-sided laminated paper. The base paper had an air permeability of 75000 seconds / 100 ml and had a tensile strength that could withstand lamination. Air permeability of single-sided laminated paper is 520,000 seconds / 100
In ml, it had a tensile strength of 3.68 kN / m and a wet tensile strength of 0.993 kN / m, and had mechanical strength enough to withstand practical use as a fumigation disinfection coating sheet.

In order to measure the gas permeability of methyl isothiocyanate, a 250 mm
A sheet having a size of × 250 mm was cut out, and attached and measured as a test sheet 14 in the apparatus shown in FIG. At this time, the sheet was attached with the biodegradable thermoplastic resin layer side facing the charging tank 1, that is, the gas generation side, and the paper layer side facing the mold 5. As shown in Table 1, the gas permeability of methyl isothiocyanate was extremely low at 2.21%, and it was found that the gas permeability of methyl isothiocyanate was high for fumigated gas.

Example 2 Softwood bleached wood pulp 20% by weight Hardwood bleached wood pulp 80% by weight and slowness 70
The mixture was beaten to SR, and 23% by weight of calcium carbonate and 2% by weight of titanium oxide were added to the wood pulp, and the pulp was made using a fourdrinier paper machine so that the basis weight was 40 g / m ² . Oxidized starch (Nippon Corn Starch Co., Ltd.)
A base paper was manufactured by size press coating a 6% by weight aqueous solution of SK-100 (trade name). This base paper was subjected to super calendering to produce a base paper for lamination having a basis weight of 41 g / m ² .

Next, using the same melt-extrusion laminator as in Example 1, 40% by weight of polybutylene succinate (Bionore # 1903, trade name, manufactured by Showa Polymer Co., Ltd.), which is a biodegradable thermoplastic resin, and polybutylene succinate were used. Nate adipate (Bionore # 30, manufactured by Showa Polymer Co., Ltd.)
30) 60% by weight is mixed and melted, and the die temperature is 260 ° C.
Was laminated on one surface of the base paper in a film shape having a thickness of 30 μm to produce a single-sided laminated paper.

Table 1 shows the physical properties of the base paper and the single-sided laminated paper. The base paper had an air permeability of 1853 sec / 100 ml and had a tensile strength that could withstand lamination. Single-sided laminated paper has air permeability of 5660,000 sec / 100
In ml, it had a tensile strength of 2.85 kN / m and a wet tensile strength of 0.757 kN / m, and had a mechanical strength enough to withstand practical use as a fumigation disinfection coating sheet.

Further, when the gas permeability was measured in the same manner as in Example 1, as shown in Table 1, the gas permeability of methyl isothiocyanate was as low as 28.0%, and the barrier property against fumigation gas was low. It turned out that there was.

Example 3 Unbleached Wood Pulp 75
25% by weight of hardwood unbleached wood pulp is beaten to a slowness of 59 ° SR, and the basis weight is 54 using a fourdrinier paper machine.
g / m ² . During the papermaking, a 3% by weight aqueous solution of polyvinyl alcohol (manufactured by Kuraray Co., Ltd., trade name PVA117H) was subjected to size press coating to obtain a basis weight of 55 g /
An m ² laminating base paper was produced.

Next, using the same melt-extrusion laminator as used in Example 1, polybutylene succinate (Bionore # 1903, trade name, manufactured by Showa Polymer Co., Ltd.) as a biodegradable thermoplastic resin was melted. , Die temperature 260 ℃
Was laminated on one side of the base paper in the form of a film having a thickness of 40 μm to produce a single-sided laminated paper.

Table 1 shows the physical properties of the base paper and the single-sided laminated paper. The base paper had an air permeability of 1185 seconds / 100 ml and had a tensile strength enough to withstand lamination. Single-sided laminated paper has an air permeability of 5,970,000 sec / 100
In ml, it had a tensile strength of 6.38 kN / m and a wet tensile strength of 1.36 kN / m, and had mechanical strength enough to withstand practical use as a fumigation disinfection coating sheet.

Further, when the gas permeability was measured in the same manner as in Example 1, as shown in Table 1, the gas permeability of methyl isothiocyanate was as low as 15.2%, and the gas permeability of methyl isothiocyanate was low. It turned out that there was. Further, when the test sheet of the laminated paper was attached to the apparatus 1, the paper layer side was reversed and the measurement was performed with the paper layer side facing the charging tank 1, that is, the gas generation side, and the gas permeability of methyl isothiocyanate was measured. The gas barrier property was slightly higher than when the biodegradable thermoplastic resin layer side was attached to the charging tank 1 side.

The gas permeability when measuring the resin layer side of the test sheet toward the charging tank 1 using chlorpicrin as a fumigant is extremely low at 4.37%, and has a high gas barrier property. Was.

Example 4 The base paper manufactured in Example 3 was used as a base paper and subjected to super calendering to manufacture a base paper for lamination.

Next, using the same melt extrusion laminator as used in Example 1, polybutylene succinate (Bionore # 1903, manufactured by Showa Polymer Co., Ltd.) as a biodegradable thermoplastic resin was melted. , Die temperature 260 ℃
Was laminated on one side of the base paper in the form of a film having a thickness of 40 μm to produce a single-sided laminated paper.

Table 1 shows the physical properties of the base paper and the single-sided laminated paper. The base paper had an air permeability of 1505 seconds / 100 ml and had a tensile strength that could withstand lamination. Single-sided laminated paper has an air permeability of 605,000 seconds / 100
In ml, it had a tensile strength of 6.33 kN / m and a wet tensile strength of 1.18 kN / m, and had mechanical strength enough to withstand practical use as a fumigation disinfecting coating sheet.

The gas permeability was measured in the same manner as in Example 1. As shown in Table 1, the gas permeability of methyl isothiocyanate was as low as 19.8%, indicating that the gas permeability was lower than that of fumigation gas. It turned out that there was.

When chloropicrin was used as the fumigant, the gas permeation rate was extremely low at 6.38%, indicating a high gas barrier property.

[Example 5] Unbleached coniferous wood pulp 75
25% by weight of hardwood unbleached wood pulp was beaten to a slowness of 53 ° SR to produce uncoated paper having a basis weight of 55 g / m ² , which was used as a base paper for lamination. Next, lamination was performed in the same manner as in Example 4 to produce a single-sided laminated paper.

Table 2 shows the physical properties of the base paper and the single-sided laminated paper. The air permeability of the single-sided laminated paper is 590,000 sec / 10
At 0 ml, it had a tensile strength of 5.76 kN / m and a wet tensile strength of 1.34 kN / m, and had mechanical strength enough to withstand practical use as a coating sheet for fumigation.

The gas permeability was measured in the same manner as in Example 1. As shown in Table 2, the gas permeability of methyl isothiocyanate was 85.9%, and the barrier property against fumigant gas was It was found to be the same as a conventionally used polyethylene film having a thickness of about 100 μm.

Example 6 A wood pulp which had not been exposed to conifers was
Beat to 45 ° SR lowness, basis weight 45g / m ^TwoNo
After making the base paper for coating,
A base paper for mining was manufactured.

Next, using the same melt-extruding laminator as used in Example 1, polybutylene succinate (Bionore # 1903, manufactured by Showa Polymer Co., Ltd.) as a biodegradable thermoplastic resin was melted. , Die temperature 260 ℃
Was laminated on one side of the base paper in the form of a film having a thickness of 20 μm, and then laminated on the opposite side in the same manner to produce a double-sided laminated paper.

Table 2 shows the physical properties of the base paper and the double-sided laminated paper. The base paper has an air permeability of 135 seconds / 100 ml,
It had a tensile strength that could withstand lamination. The double-sided laminated paper has an air permeability of 600,000 seconds / 100 ml, a tensile strength of 5.20 kN / m, and a wet tensile strength of 1.
It was 25 kN / m and had mechanical strength enough to withstand practical use as a fumigation disinfection coating sheet. Further, a 250 mm × 250 mm sheet was cut out from the double-sided laminated paper, and the methyl isothiocyanate gas permeability was measured. As shown in Table 2, it was found that a barrier property against fumigation gas equivalent to that of a conventionally used polyethylene film having a thickness of about 100 μm was obtained.

[Comparative Example 1] Using only the base paper for lamination manufactured in Example 3, that is, unbleached kraft paper, the methyl isothiocyanate gas permeability was measured. Table 3 shows the physical properties and gas permeability of this kraft paper. The gas permeability was 100%, and kraft paper without lamination alone had almost no gas barrier properties.

[Comparative Example 2] Polybutylene succinate (Bionore # 1903, manufactured by Showa Polymer Co., Ltd.), which is a biodegradable thermoplastic resin, was melted, and its thickness was adjusted to 4 by the T-die method.
A 0 μm film was produced. Using this film, the gas permeability of methyl isothiocyanate was measured. Table 3 shows the physical properties and gas permeability of this resin film. The gas permeability was 96.7%, and the biodegradable thermoplastic resin film alone that was not laminated on the base paper had almost no gas barrier properties.

The laminated paper of Example 3 is the same as Comparative Example 1
It is apparent that the laminating significantly improves the fumigation gas barrier property by laminating the base paper with the biodegradable thermoplastic resin layer of Comparative Example 2 on the base paper.

Comparative Example 3 Using a commercially available polyethylene film having a thickness of about 0.1 mm (manufactured by Shin-Etsu Polymer Co., Ltd.), the methyl isothiocyanate gas permeability and the chloropicrin gas permeability were measured. Table 3 shows the physical properties and gas permeability of the polyethylene film. The gas permeability was 86.6% and 72.4%, respectively, and the gas barrier properties of the polyethylene film were unexpectedly low.

[0073]

[Table 1]

[0074]

[Table 2]

[0075]

[Table 3]

[Example 7] Parasitic pine sawyer
Fumigation disinfection test of log.
1.8m logs are piled in a girder and carbum agent (Carbum 5)
0.5 l / m³And 1.0 l / m ³Dose of
Sprayed on the surface of the integrated material so that
Or a commercially available polyethylene sheet (0.1 mm thick)
The material was coated. Example 1
Using laminated paper manufactured by the method of
As the sheet, the same sheet as that used in Comparative Example 3 was used.
Each of the sheets had a size of 4 mx 4 m.
The hem of the seat was embedded in the soil. Coated sheet during fumigation
The internal temperature was 13 ° C. at the highest and changed at about 7 ° C. at the minimum. 1
After fumigation for 4 days, the logs are split and the pine sawyer beetle larvae
Was investigated for life and death.

The results are shown in Table 4, where 0.5 l / m
^Three live larvae were observed only in the section treated with ³ doses and covered with a polyethylene sheet. In other wards, all 10
The mortality was 0%. In addition, the mortality rate is obtained by dividing the treated log into small pieces, confirming the life and death of the found insects, and expressing the percentage of dead insects as a percentage. In addition, the appearance of the sheet made of the laminated paper of Example 1 was observed during the fumigation period. As a result, the sheet was not damaged even though the day of the strong wind continued, and sufficient strength was exhibited.

[0078]

[Table 4]

Example 8 Soil Fumigation Disinfection Test (Toma
Test for controlling the effect of toy wilt) Obtained by shaking culture in potato / shoe-closed liquid medium
10 tomato wilt fungi ⁵Incorporate soil / equivalent amount of dry soil
did. 2 chlorpicrine treatment areas and 1 non-treatment area
And each section was provided with 50 planting holes. Chlorpicrin
On the day after inoculation, chlorpicrin (chlorpiric)
(With 80% clean) at a depth of 3 ml per planting hole
Injected 15 cm. Sheet of the present invention immediately after chemical treatment
(Laminated paper obtained in Example 1) or commercially available polye
It was covered with a styrene sheet (thickness: 0.05 mm). Sheet
Was 4 m × 4 m. 10 days later
The coating is removed and after another 5 days, chlorpicrin treatment
Ward, untreated ward each 50 tomato seedlings (cultivar: strong rice life 2
No.) was planted.

Table 5 shows the results of a disease investigation conducted three months later. In the plot covered with the sheet made of the laminated paper of Example 1, the occurrence of wilt was more strongly suppressed than in the plot coated with the commercially available polyethylene sheet. The onset of wilt was determined by the following equation, with the onset index determined by the degree of browning of the tomato stem conduit as follows. Disease severity = Σ (number of strains by disease severity x disease index) x 100 / number of researched strains x 3

[0081]

[Table 5]

[0082]

The covering sheet for fumigation disinfection according to the present invention comprises:
By burying in soil, it will biodegrade and disappear,
The cost of collection and disposal is low, and it does not impair the beautification of the environment by remaining semipermanently even if left after fumigation treatment like conventional plastic sheets and films. In addition, no harmful substances are discharged by incineration treatment or landfill treatment, and environmental destruction such as softening of the landfill is not caused. The covering sheet for fumigation disinfection according to the present invention,
The use of expensive biodegradable thermoplastic resin films and fumigants is achieved by combining biodegradable plastic films with paper to achieve high barrier properties against fumigant gas that cannot be exhibited by each material alone. And is useful for reducing the cost of fumigation treatment.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a testing device for fumigation gas barrier properties.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Input tank 2 Permeation tank 3 Communication hole of charging tank 4 Communication hole of transmission tank 5 Formwork 6 Upper cock of charging tank 7 Lower cock of charging tank 8 Ceiling cock of charging tank 9 Upper cock of transmitting tank 10 Lower of transmitting tank Cock 11 Ceiling cock of charging tank 12 Packing 13 Packing 14 Test sheet

 ──────────────────────────────────────────────────続 き Continued on the front page (71) Applicant 596129008 Taiyo Corporation 6-5-3 Sotokanda, Chiyoda-ku, Tokyo (71) Applicant 599099526 Kowa Corporation 2239-8 Moro, Kanuma-shi, Tochigi Prefecture (72) Inventor Yoshiaki Ishino 90-2 Eo, Fuji-shi, Shizuoka Prefecture Inside Mishima Paper Co., Ltd.Development Research Laboratory (72) Inventor Junyuki Hattori 90-2 Eo, Fuji-shi, Shizuoka Prefecture Mishima Paper Co., Ltd.Development Laboratory (72) Inventor Abe Yutaka 6-14-10 Futako, Takatsu-ku, Kawasaki City, Kanagawa Prefecture (72) Inventor Keiji Shiomi 1-13-13 Shiba-Daimon, Minato-ku, Tokyo Showa Denko Co., Ltd. (72) Mikio Kondo Inventor Taiyo Co., Ltd. (72) Kayotani Minoru 2239-8, Moro, Kanuma-shi, Tochigi Pref. Consideration) 2B121 AA11 AA16 CA13 CA64 CA67 CC02 EA24 FA15 4F100 AJ04A AK01B AK01C AK21 AK41 BA02 BA03 BA06 BA10B BA10C BA13 DG10A GB01 JB16B JB16C JC00B JC00C JD02A JL00 YY00A4H01 DD0104A04

Claims (6)

[Claims] 1. A fumigation disinfection coating sheet comprising a biodegradable thermoplastic resin layer laminated on at least one surface of a base paper comprising a cellulose component. 2. It is made of a cellulose component and has an air permeability of 300.
A fumigation disinfection coating sheet comprising a biodegradable thermoplastic resin layer laminated on one side of a base paper having a speed of at least 100 seconds / 100 ml. 3. It is made of a cellulose component and has an air permeability of 130.
A fumigation disinfection coating sheet comprising a biodegradable thermoplastic resin layer laminated on both sides of a base paper having a speed of at least 100 seconds / 100 ml. 4. The air permeability of the base paper is 1000 seconds / 100 ml.
The covering sheet for fumigation disinfection according to any one of claims 1 to 3, characterized in that: 5. A method of fumigating disinfected dead wood with pests, wherein the dead wood is treated with a fumigant and covered with the fumigation disinfection coating sheet according to any one of claims 1 to 4. Disinfection method. 6. A method for fumigating a soil, wherein the soil treated with a fumigant is covered with the covering sheet for fumigation according to any one of claims 1 to 4.