JPH0662681A - Mulching sheet - Google Patents

Abstract

PURPOSE:To obtain a mulching sheet, having waterproofness and corrosion resistance and decomposable with microorganisms in soil after the passage of a mulching period by supporting an antimicrobial and antiblastic agent in a substrate sheet composed of crepe natural kraft paper having a specific basis weight, coating or impregnating the substrate sheet with a silicon resin and curing thea silicone resin. CONSTITUTION:The mulching sheet is obtained by using crepe natural kraft paper having 20-450g/m<2>, preferably 30-150-g/m<2> basis weight as a substrate for the mulching sheet. Basic calcium copper sulfate, a cuprammonium complex salt, beta-hydroxyquinoline, a benzimidazole-based, a dicarboximide-based or a polyhaloalkylthio-based germicide, etc., are cited as an antimicrobial and antiblastic agent. An organopolysiloxane is cited as the silicone resin to be coated, impregnated and cured. This mulching sheet is capable of regulating the corrosion period in soil by the amount of the antimicrobial and antiblastic agent supported and decomposable by microorganisms in the soil after completing the mulching operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet for mulching cultivated land, and there is no need to remove the sheet after performing the mulching function, and moreover, a predetermined period in which mulching is required. Provide a mulching sheet that will not rot during the process.

[0002]

2. Description of the Related Art In order to adjust the growth of crops such as horticultural crops and vegetables and to increase the sweetness of fruits, for example, a method of laying straw or the like near the root of the crop and adjusting the temperature and humidity around it. Has been practiced since ancient times.

In recent years, a mulching sheet consisting of a winding roll of a plastic film such as a polyethylene resin film has been laid by a machine in a vast area after tilling in place of straw or the like. By mulching the mulching sheet, the moisture contained in the soil is retained and nutrients in the soil are prevented from flowing out by rainwater during the growing period of the crop.

However, since the mulching sheet made up of the above-mentioned plastic film winding roll has extremely good fastness properties, it has a remarkably long life as compared with the period in which mulching is required. , It remains without decomposition over a long period of time, which makes it impossible to reuse vast agricultural land.

Soil contamination caused by a mulching sheet consisting of a roll of plastic film can be prevented by collecting the mulching sheet at the end of the growing season of the crop. Takes a lot of time and leads to soaring costs.

In addition, in recent years, regulations on abandonment of plastic materials that are difficult to corrode are becoming strict,
There are severe restrictions on the use of plastic films as mulching sheets that are left on farmland after mulching. Further, even when the unnecessary mulching sheet after having fulfilled the function of mulching is collected by taking time and effort, the mulching sheet made of the plastic film is
_Since harmful substances such as _x , SO _x , and CO are emitted into the atmosphere, there is a problem of air pollution, and further, there is a drawback that the incinerator is damaged because high temperature is required for incineration.

[0007] From the above, the handling workability as a mulching sheet is good, and the original purpose of the mulching sheet is achieved during the growing period of the crop, and the crop after the mulching function is fulfilled. A mulching sheet having a property of being naturally decomposed by the action of microorganisms in the soil after the lapse of the growing period is desired, and as a mulching sheet satisfying such a property, for example, JP-A-60- No. 250949 proposes that a surface of crepe natural kraft paper is coated with a latex dispersion of polyvinylidene chloride and dried.

[0008]

[Problems to be Solved by the Invention] A mulching sheet obtained by coating a latex dispersion of polyvinylidene chloride on the surface of the above-mentioned crepe natural kraft paper and drying it is used when the mulching action during the growing period of the crop is finished. Has a property of being sufficiently decomposed by the action of microorganisms in the soil, and can solve the problem of having to collect the laid mulching sheet. However, this mulching sheet is not sufficiently waterproof when a large amount of water is in contact with the surface of the mulching sheet for a long time, and the waterproof function cannot be sufficiently performed during the mulching period. Moreover, the air permeability is insufficient as a mulching sheet.

A mulching sheet for solving this problem,
That is, not only it has good properties such as air permeability and strength required for the mulching sheet, but during the period of several months when mulching is required, a large amount of water is left on the surface of the mulching sheet. As a mulching sheet with sufficient waterproofness that does not impair the original function of mulching even if it may come in contact with time, a base sheet made of crepe natural kraft paper, 0.5 to 20.0 wt% of the base sheet (d
An attempt was made to use a mulching sheet coated with, impregnated with, and cured with a silicone resin of ry).

However, the mulching sheet made of crepe natural kraft paper coated, impregnated and hardened with the silicone resin has a portion buried in the soil or a portion in contact with the soil caused by bacteria in the soil. It was confirmed that the part embedded in the soil and the part in contact with the soil would be corroded in a few weeks due to decomposition.

Generally, the mulching sheet may be required to have a property of corroding after about 1 month since the mulching sheet becomes unnecessary after 1 month depending on the plant to be used. In the case of fruit trees such as tangerines and peaches, rainwater does not penetrate to increase the sugar content of the fruits, and it has moisture permeability to evaporate excess moisture in the soil, and these functions are 3 ~. It is required that it be played for four months. Also lettuce, cabbage,
In the case of planted vegetables such as Chinese cabbage, it is required to be light-impermeable from the viewpoint of weeding action and to perform a mulching function for 1 to 6 months.

On the other hand, the present invention not only has good properties such as air permeability and strength required for the mulching sheet, but also requires mulching.
During the desired period of up to several months, even if a large amount of water may come in contact with the surface of the mulching sheet for a long time, it does not impair the original function of mulching. It has excellent waterproofness, and it does not corrode until the period of time required for mulching, and it does not corrode when the period of time required for mulching has elapsed. (EN) Provided is a mulching sheet which has the property of decomposing and can be easily incinerated when it is recovered by a removal operation after having performed the function of mulching.

[0013]

In the present invention, a base sheet made of crepe natural kraft paper having a specific basis weight is used, on which an antibacterial / antibacterial agent is supported, and a silicone resin is applied. By impregnating and curing, the above-mentioned various problems were solved.

That is, the mulching sheet of the present invention is a base sheet made of crepe natural kraft paper having a basis weight of 20 to 450 g / m ² , and 0.01 to 4 of the base sheet.
An anti-bacterial agent of 0.0 wt% (dry) is carried, and 0.5 to 20.0 wt% (dry) of the base sheet.
Silicone resin has been applied, impregnated and cured, and 100-230 ml / min. cm ² . 10 cmH
_It consists of a sheet with an air permeability of ₂ O.

In the mulching sheet of the present invention having the above structure, the crepe natural kraft paper used as the base sheet has a basis weight of 20 to 450 g / m ^2, preferably 3
It is from 0 to 150 g / m ² . When the basis weight of the crepe natural kraft paper is less than 20 g / m ² , it is not possible to maintain sufficient strength required for the mulching sheet, and when the basis weight exceeds 450 g / m ² , the sheet thickness is increased. The handling characteristics of the mulching are deteriorated due to poor handling due to the height.

As the antibacterial / antibacterial agent to be carried on the base sheet made of crepe natural kraft paper having a basis weight of 20 to 450 g / m ² , inorganic metal antibacterial agents, sulfur agents, organic chlorine-based bactericides, organic phosphoric acid sterilizers There are agents, antibiotics, benzimidazole fungicides, dicarboximide fungicides, polyhaloalkylthio fungicides, soil fungicides, ceramics, etc. Among them, inorganics that use metals such as copper, zinc, silver and gold. Metal antibacterial agents and antibacterial agents composed of ceramics are preferable, and among the inorganic metal antibacterial agents, copper-based ones are particularly preferable in terms of practicality and cost. Further, as an antibacterial agent comprising an inorganic copper agent, basic copper calcium sulfate, an aqueous solution of a copper ammonium complex salt, basic copper chloride, basic copper sulfate, a mixture of basic copper sulfate and sulfur, cupric hydroxide, A mixture of anhydrous copper sulfate and anhydrous sodium carbonate or the like can be used. Further, 8-hydroxyquinoline can be used as an antibacterial agent composed of an organic copper agent.

By increasing the amount of the antibacterial agent carried on the base sheet, the period until the portion of the mulching sheet embedded in the soil or the portion in contact with the soil is corroded can be extended. . For example, when a mulching period of about 3 to 4 months is required, 0.1 to 20.0% by weight (dry) of the anti-bacterial agent of the base sheet made of crepe natural kraft paper may be loaded. good.

The silicone resin coated, impregnated, and cured on the base sheet made of crepe natural kraft paper is made of organopolysiloxane in which an organic group is bonded to a silicon atom of a skeleton formed by a siloxane bond. It may be an addition curing type or a condensation polymerization type, and may be a heat curing type, an ultraviolet curing type, an electron beam curing type or the like. Furthermore, the coating agent applied to the base sheet made of crepe natural kraft paper may be any of solvent-based, water-based and emulsion-based coatings, and the ratio of the base sheet is 0.5 to 20.0% by weight (dry). Applied by coating or impregnation and cured. When the amount of the silicone resin coated and impregnated on the base sheet is less than 0.5% by weight (dry) of the base sheet, the waterproof function of the silicone resin is exerted throughout the thickness of the base sheet. It becomes difficult to do so, the waterproof performance tends to be insufficient during the mulching period, and the strength of the sheet when wet with water becomes insufficient. In addition, the silicone resin coated and impregnated on the base sheet is the base sheet 2
Even if it exceeds 0.0% by weight (dry), the ratio of using a large amount of expensive silicone resin does not lead to the improvement of the waterproof performance of the mulching sheet, and it is also a factor that lowers the air permeability. Become.

A base sheet made of crepe natural kraft paper having a basis weight of 20 to 450 g / m ² is coated with 0.0 of the base sheet.
1 to 40.0% by weight (dry) of the anti-bacterial agent is carried and 0.5 to 20.0% by weight of the base sheet.
The mulching sheet of the present invention obtained by coating, impregnating and curing a silicone resin at a ratio of (dry) needs to have the usual air permeability required for the mulching sheet. That is, under a pressure difference of 10 cmH ₂ O, 1c
The amount of air passing through the area of m ² is 100 to 230 ml /
min. cm ² . It has an air permeability of 10 cmH ₂ O. The air permeability in the mulching sheet of the present invention is determined by the basis weight of the crepe natural kraft paper used as the base sheet, the type of silicone resin coated, impregnated and cured on the base sheet, and the silicone resin It is adjusted by the combination with coating and impregnation amount.

In the mulching sheet of the present invention having the above-mentioned structure, the crepe natural kraft paper used as the base sheet is immersed in a solution of an antibacterial / antibacterial agent, dried, and then treated with a silicone resin solution. Alternatively, the crepe natural kraft paper used as the base sheet may be treated with a silicone resin solution containing an antifungal agent.

[0021]

The mulching sheet of the present invention has a basis weight of 20-4.
In a base sheet made of crepe natural kraft paper of 50 g / m ² , 0.01 to 40.0% by weight of the base sheet (d
ry) anti-bacterial agent is supported, and 0.5 to 20.0% by weight (dry) of the base material sheet is coated, impregnated and cured, and 100 to 230.
ml / min. cm ² . It has an air permeability of 10 cmH ₂ O.

In the mulching sheet of the present invention having the above-mentioned constitution, since the base material sheet is made of crepe natural kraft paper, it has excellent elongation characteristics. Therefore, the mulching sheet is stepped on during or after mulching. Even if a force is concentrated on a specific point of the seat due to damage, etc., the periphery of the seat stretches and absorbs the force, resulting in excellent damage resistance. . Further, since the mulching sheet of the present invention has flexibility throughout the sheet by the crepe of the base material sheet, it exhibits an excellent workability during mulching work. Furthermore, the kraft paper used as the base sheet brings opacity to the mulching sheet of the present invention and therefore also has a weed-preventing action.

Furthermore, since the silicone resin coated, impregnated and cured on the base sheet made of crepe natural kraft paper has a small surface tension and has excellent penetrability into paper, the crepe natural crepe which is the base sheet is used. The surface and entanglement points of the pulp fibers constituting the kraft paper are covered with the silicone resin, and the sheet is permanently waterproofed. Further, since the silicone resin has extremely weak film forming properties, 0.5 to 20.0% by weight (dr) of the base sheet is used for the crepe natural kraft paper which is the base sheet.
The silicone resin applied in the ratio of y) does not almost completely fill the voids between the fibers, and the voids between the fibers are left as they are. Sufficient air permeability is ensured without hindering

Further, the mulching sheet of the present invention contains 0.01 to 40.0% by weight (dry) of the base sheet.
Since the anti-bacterial agent is carried, it is difficult for the bacteria in the soil to decompose the cellulose embedded in the soil or the portion in contact with the soil. Then, the period in which the part embedded in the soil or the part in contact with the soil is decomposed by the bacteria in the soil can be controlled by the amount of the antibacterial agent carried on the base material sheet. Therefore, the amount of the anti-bacterial agent to be carried may be adjusted according to the period when mulching is required for the target crop.

In addition, although the mulching sheet of the present invention maintains the waterproof performance for a relatively long period due to the presence of the silicone resin applied to the base sheet, the base sheet itself is made of natural kraft paper. Since it is formed, it is sufficiently subjected to the decomposition action of microorganisms in the soil, so that it naturally spoils after the required mulching period, and thus the labor for recovery after mulching is not required.

In addition, the mulching sheet of the present invention can be subjected to a simple incineration treatment when it takes time and is collected after having fulfilled the function of mulching.

[0027]

EXAMPLES The specific constitution of the mulching sheet of the present invention will be described below with reference to examples.

[Examples 1 to 7] A base sheet made of crepe natural kraft paper having a basis weight of 100 g / m ² was prepared in [Table 1].
Of the anti-bacterial agent of the type described in the above prescribed column, hot air drying is performed, and then a silicone resin [Shin-Etsu Chemical Co., Ltd .: KS778, catalyst: PL-8] liquid is further added. After dipping in a coating liquid obtained by diluting with toluene at room temperature for 1 minute and squeezing with a chilled-chilled roll, 12
By curing by heating at 0 ° C. for 3 minutes, 7 types of mulching sheets, which were the examples of the present invention, were obtained.

[Examples 8 to 9] A base sheet made of crepe natural kraft paper having a basis weight of 100 g / m ² was coated with a silicone resin [Shin-Etsu Chemical Co., Ltd .: KS778, catalyst: PL].
-8] The solution was further diluted with toluene, and then immersed in a coating solution containing an antibacterial agent of the type described in the predetermined column of [Table 1] at room temperature for 1 minute to chill the solution. After squeezing with a chilled roll, the silicone resin was cured by heating at 120 ° C. for 3 minutes to obtain two types of mulching sheets, which were examples of the present invention.

Each of the mulching sheets made of the above-mentioned examples was placed in a humidity control chamber at 20 ° C. and 65% RH for 24 hours.
After being left for a period of time, the amount of the antibacterial / antibacterial agent carried on the base sheet (% by weight of the antibacterial / antibacterial agent on the base sheet
y)) and the amount of silicone resin attached to the base sheet (weight% (dry) of the resin relative to the base sheet) were measured. The results are also shown in [Table 1].

[0031]

[Table 1]

The anti-bacterial agents in [Table 1] are as follows. (* 1) ・ ・ ・ ・ Taisho Co., Ltd. (* 2) ・ ・ ・ ・ Fine Chemical (* 3) ・ ・ ・ ・ Griffin (* 4) ・ ・ ・ ・ Nippon Pesticides

Comparative Example 1 A base sheet made of crepe natural kraft paper having a basis weight of 100 g / m ² was prepared as a mulching sheet for comparison.

[Comparative Example 2] A base sheet made of crepe natural kraft paper having a basis weight of 100 g / m ² and a solid component of 30 was added.
Weight% silicone resin [Shin-Etsu Chemical Co., Ltd .: KS7
78, catalyst: PL-8] liquid was further diluted with toluene to be dipped in a coating liquid at room temperature for 1 minute, and chilled-
After squeezing with a chilled roll, it is cured by heating at 120 ° C. for 3 minutes to give 2.0 to the base sheet.
A mulching sheet for comparison with a dry weight% silicone resin attached was obtained.

[Experiment 1] Test pieces obtained by cutting the mulching sheets of the example product and the comparative example product into 8.0 cm × 10.5 cm were embedded in the soil for the lower half of each test piece for 3 months. After standing, the corrosion state of each test piece was confirmed, and a corrosion resistance test was performed. The results are as follows: ◯ ・ ・ ・ Corrosion hardly occurs, △ ・ ・ ・ ・ ・ ・ Corrosion occurs only at the interface between the soil and the atmosphere, × ・ ・ ・ ・ ・ ・-It was evaluated that the entire part buried in the soil was corroded.

A paper cup made of each mulching sheet was filled with water, and the state in which water drained to the back side of the paper cup was visually confirmed after 24 hours, and a water repellency test was conducted. The result is ○ ・ ・ ・ ・ ・ ・ Almost no water leakage, △ ・ ・ ・
・ ・ Slight water leakage, × ・ ・ ・ Evaluated because of water leakage.

The results are shown in Table 2 together with the air permeability (ml / min.cm ² .10 cmH ₂ O) of each mulching sheet.

[0038]

[Table 2]

[Experiment 2] Various physical properties of the mulching sheet of the example product and the comparative example product were measured after leaving them in a humidity control chamber at 20 ° C. and 65% RH for 24 hours. The results are shown in [Table 3].

[0040]

[Table 3]

[0041]

[Effect] The mulching sheet of the present invention has a basis weight of 20 to 4
In a base sheet made of crepe natural kraft paper of 50 g / m ² , 0.01 to 40.0% by weight of the base sheet (d
The anti-bacterial agent of ry) is carried, and the silicone resin is coated, impregnated and cured at a rate of 0.5 to 20.0% by weight (dry) of the base sheet, and 100 to Two
30 ml / min. cm ² . It has an air permeability of 10 cmH ₂ O, and can be used for mulching of the part that is buried in the soil or the part that is in contact with the soil, simply by changing the amount of the anti-bacterial agent carried according to the desired mulching period. It is possible to control the period until the sheet corrodes.

For this reason, the mulching sheet of the present invention having the above-described structure can be applied to the mulching sheet in the soil even during the required mulching period, even if the portion is buried in the soil or is in contact with the soil. It does not corrode due to the action of microorganisms, but has the property of being sufficiently decomposed by the action of microorganisms in the soil when the action of mulching is finished.

Further, when the mulching action is finished and the product is recovered by the removal work, the incineration can be easily carried out.

Further, during the period when mulching is required, even if a large amount of water is in contact with the surface of the mulching sheet for a long time, the original function of mulching is impaired. It has sufficient waterproofness, and has good breathability and sufficient strength, which are the basic properties originally required for a mulching sheet.

Claims (1)

[Claims] 1. A base sheet made of crepe natural kraft paper having a basis weight of 20 to 450 g / m ² carries 0.01 to 40.0% by weight (dry) of the antibacterial / antibacterial agent of the base sheet. At the same time, 0.5 to 20.0% by weight (dry) of the base material sheet has been coated, impregnated and cured, and 100 to 230 ml / min. cm ² .
A mulching sheet having an air permeability of 10 cmH ₂ O.