JP2000342082A - Mulching paper sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a mulching paper sheet having a suppressing effect on soil temperature-elevation and a growth-promoting effect on plants and excellent in weed-preventing effect and mechanical spreading property in the outdoor by having a specific breaking elongation rate and also forming it of 2 layers consisting of a light-reflecting layer and a colored pulp layer. SOLUTION: This mulching paper sheet has 3-20% breaking elongation rate in papermaking direction based on JIS P 8132, and consists of 2 layers of a light-reflecting layer and a colored pulp layer. In this case, the colored pulp layer preferably contains at least one kind selected from fumic acid, a fumic acid salt and carbon black. Also, the colored pulp layer can be obtained by paper forming with a wet type papermaking machine using a cellulose pulp as a main component, and it is possible to select the raw material blending ratio of a wood pulp with a waste paper pulp optionally in this case.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper multi-sheet, and more particularly to a paper multi-sheet having an effect of promoting plant growth while suppressing an excessive rise in soil temperature and having a high effect of preventing weeds.

[0002]

2. Description of the Related Art Conventionally, a polyolefin-based plastic film multi-sheet has been used in agriculture to prevent the occurrence of weeds, keep warm, and maintain soil moisture when growing a target plant. In addition, a film multisheet of a type in which aluminum is directly vapor-deposited or kneaded on these surfaces to reflect light to promote the growth of fruits and to repel pests is also on the market. However, since these film multi-sheets have almost no biodegradability, it is necessary to collect and dispose of used films, which burdens agricultural workers.

[0003] On the other hand, proposals have been made on a paper-made multi-sheet that makes use of the characteristics of paper that corrodes and decomposes in soil.
JP-A-9-176838 describes a chitosan paper laminate in which an adhesive layer and an aluminum vapor-deposited layer are provided on the surface of a chitosan paper layer made of wood pulp, and a method for producing the same. However, in the case of a paper base material having poor surface smoothness, it is very difficult to provide a mirror surface for reflecting sunlight at the surface, and a metal vapor-deposited layer having a high mirror surface only by a transfer method called a so-called casting method. It is impossible to provide. In addition, when a metal layer is directly deposited on the paper surface, it is possible to impart a certain reflection ability, but due to insufficient reflection of sunlight, there is a concern that weeds may be generated due to light transmitted through the sheet. .

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a paper multi-sheet having an effect of suppressing a rise in soil temperature and an effect of promoting the growth of plants, and a high effect of preventing weeds and having excellent mechanical extensibility outdoors. It is in.

[0005]

DISCLOSURE OF THE INVENTION The present inventors have conducted intensive studies on a paper multi-sheet having an effect of suppressing a rise in soil temperature and an effect of promoting the growth of plants and also having a high effect of preventing weeds. The present invention has found a method for providing a light reflection layer for promoting the growth of plants and plants by vapor deposition, coating, printing, and the like, and further blocking and absorbing transmitted light by coloring the paper base material to prevent the occurrence of weeds. Was completed.

[0006] The present invention relates to a paper multi-sheet characterized by having a breaking elongation in the papermaking direction of 3 to 20% based on JIS P 8132 and comprising two layers of a light reflecting layer and a colored pulp layer. .

Further, the present invention is characterized in that the colored pulp layer contains at least one selected from humic acid, humic acid salt and carbon black.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The colored pulp layer in the paper multi-sheet of the present invention is obtained by making paper from a cellulose pulp as a main component using a wet paper machine, and the mixing ratio of wood pulp and waste paper pulp may be adjusted appropriately. Selected. Used paper pulp may be any of used corrugated cardboard paper, used newspaper paper, etc., and there is no limitation depending on the type of used paper. When used paper pulp is used, light scattering is large because there are many fine fibers having a large surface area, and light absorption is large because coloring impurities such as ink are attached, so that the light blocking rate is high. The basis weight of the paper is not particularly limited.
Suitably selected in the range of to 200 g / m ^2. If the grammage is less than 30 g / m ² , the strength of the paper multi-sheet cannot be maintained for a certain period after multi-stretching, and if the grammage exceeds 200 g / m ² , the weight of the paper,
The value of the thickness is too large, making the spreading work difficult. When the basis weight is low, it is preferable to use softwood unbleached kraft pulp (NUKP) to improve the strength of the paper multi-sheet.

[0009] Examples of agents used for coloring include humic acid, humates, carbon black and the like. Humate is a humic acid salt called humic acid, which is obtained by neutralizing young coal (lignite, lignite, etc.) with alkali.
Types include alkali metal salts and ammonium salts.
Although humic acid itself is insoluble, monovalent metal salts are water-soluble, and form chelate bonds with divalent or higher valent metals to form insoluble salts. Therefore, it is added as a water-soluble monovalent salt, but is fixed as humic acid or a divalent or higher valent metal salt of humic acid in the colored layer of the paper multi-sheet. The humate may be added in an amount of 0.05 to 15% by weight, preferably 1 to 5% by weight, based on the pulp. If the amount is less than 0.05% by weight, there is almost no increase in the light-shielding ratio, and if it exceeds 15% by weight, the light-shielding ratio does not improve, and the effect levels off. The addition method is
An aqueous solution of humate having a concentration of 15 to 20% by weight may be added to the raw material slurry, and a metal salt having a valence of 2 or more may be added for papermaking.

The amount of carbon black to be added is 0.05 to 15% by weight, preferably 1 to 5% by weight, based on pulp.
Just use it. If it is less than 0.05% by weight, the light-shielding rate hardly increases, and if it exceeds 15% by weight, the light-shielding rate is not further improved.

Other coloring agents include pigments such as acetylene black, bone black, graphite, iron black, mineral black, aniline black, iron oxide, amber, permanent brown and para brown, and CIDirect.
Black 19, CIDirect Black 22, CIDirect Black 3
2, CIDirect Black 38, CIDirect Black 51, CID
irect Black 56, CIDirect Black 62, CIDirect Bl
ack 71, CIDirect Black74, CIDirect Black 75,
CIDirect Black 77, CIDirect Black 105, CIDir
ect Black 106, CIDirect Black 107, CIDirect Bl
ack 108, CIDirect Black 112, CIDirect Black 11
3, CIDirect Black 132, CIDirect Black 146, C.
I.Direct Black 194, CIAcid Black 1, CIAcid Bla
dyes such as ck2 and CIAcid Black 346.

The light reflecting layer is provided on the colored pulp layer by metal deposition, printing and coating. The method may be selected in consideration of the level of light reflectivity according to the crop used and the environmental conditions. In the case of vapor deposition, either a direct vapor deposition method or a transfer vapor deposition method may be used. The direct vapor deposition method is a method in which a resin is applied to the surface of a base material to form a smooth resin layer, and a metal vapor generated by being heated by an evaporation source is adhered thereto to form a uniform glossy metal layer. is there. The transfer vapor deposition method is a method in which a metal is vapor-deposited on a film, the substrate is bonded to a metal layer via an adhesive, the film is peeled off, and the metal layer is transferred to the substrate.
In the case of printing, silver ink made by mixing aluminum powder or aluminum paste in which aluminum powder is dispersed in a petroleum solvent into a vehicle, or silver pearl pigment or aluminum powder made by coating mica with titanium oxide Is mixed with a transparent and light-colored ink. When the leafing type aluminum powder is used to increase the sunlight reflection, the scale-like aluminum particles are arranged on the surface layer and irregularly reflected, and the degree of reflection is further increased. The printing method is not particularly limited, such as plain format, gravure, and screen. In the case of coating, a paint having a metallic luster mainly by a pearl pigment is used. The coating method is not particularly limited, such as bar coating, air knife coating, roll coating, and blade coating.

[0013] In many cases, the multi-sheet is stretched by hand in house cultivation and the like, and the stretchability is not particularly required.
In outdoor cultivation, there is much mechanical stretching, and the extensibility of the multi-sheet becomes an important workability. In other words, the shape of the place to be extended is various such as flat ridge, flat high ridge, round ridge, and the like. Since the sheet is stretched while being pulled to conform to these shapes, the sheet is not provided with an appropriate extensibility. Is torn and useless. The required elongation may be 3 to 20%, preferably 5% or more in terms of tensile elongation at break in the papermaking direction. If the elongation at break is less than 3%, it is easily broken during mechanical stretching, and even if the elongation at break exceeds 20%, there is no difference in handleability. In order to impart elongation, any of elongation imparting processing, crepe processing, and the like may be used.

Further, even after these processes, printing, coating and vapor deposition for providing the light reflecting layer can be carried out without any problem, and the desired level of the reflecting layer can be easily provided.

[0015] The paper multi-sheet obtained by the present invention is provided with a light reflection layer on the surface for suppressing the rise in ground temperature and promoting the growth of plants by vapor deposition, coating, printing, etc., and furthermore, by coloring the paper base material, it transmits light. Blocks and absorbs light to prevent weed development. Also, since it has excellent extensibility, it can withstand mechanical stretching outdoors.

[0016]

EXAMPLES In order to make the present invention more comprehensible,
Examples are shown below, but the following examples do not limit the present invention. The percentage in the text indicates the solid content weight%. Example 1 After preparing a slurry having the following composition, papermaking was carried out by a fourdrinier paper machine, subjected to clupak processing to give elongation, and a paper multi-sheet having a basis weight of 50 g / m ² and a breaking elongation of 4.5%. Base paper was manufactured. Softwood unbleached kraft pulp (CSF 350ml) 60% Waste paper pulp 40% Internal sizing agent vs. pulp 0.6% (Product name Size Pine E, Arakawa Chemical Co., Ltd.) Sulfuric acid band (to adjust to pH 4.5) Pulp 5.0% Sodium humate (trademark: CH-02, manufactured by Terunite) to pulp 3.0% Next, 5 g of an ink containing a metal powder pigment having the following composition was used.
/ M < ² > plain printing to obtain a paper multi-sheet. Ink aluminum powder with metal powder pigment 55% Rosin-modified phenolic resin varnish 30% Gel varnish 9% Extra varnish 3% Dryer 3%

Example 2 A 250-A-thick aluminum vapor-deposited layer is formed on a biaxially-stretched polypropylene film on a paper base material of Example 1 by a vacuum vapor-deposition machine, and a two-component curable polyurethane-based adhesive is applied to the surface thereof. It was applied and bonded to the above substrate. Then 40
The adhesive was cured by being left for 24 hours in an environment of ° C., and the polypropylene film of the transfer material was peeled off to obtain a paper multi-sheet having a light reflecting layer.

Comparative Example 1 An aluminum vapor-deposited film having a thickness of 6 μm (trade name: Tokan Bochu Silver L, manufactured by Tokan Kogyo Co., Ltd.).

Comparative Example 2 A paper multi-sheet in which the basis weight and the manner of providing the light reflecting layer were the same as in Example 1 except that sodium humate was not added.

Comparative Example 3 The raw material, chemical composition, basis weight, and method of providing the light reflecting layer of the base paper were the same as in Example 1, but the elongation at break was 1.9% without imparting extensibility by clupak processing. Paper multi sheet.

Comparative Example 4 The paper substrate of Example 1 was a paper multi-sheet.

Each of the multi-sheets obtained in Examples 1 and 2 and Comparative Examples 1 to 4 was spread by hand tension on the flat ridge shown in FIG. A cultivation experiment was performed on. Table 1 shows the test results. 1. Ground Temperature Measurement Test A temperature sensor was embedded 5 cm below the surface of the ridge shown in FIG. 1 to measure the ground temperature. From Table 1, when using the paper multi-sheets of Examples 1 and 2 and Comparative Examples 2 to 4 as compared with the film multi of Comparative Example 1, the soil temperature could be lowered by the diffusion effect of the underground steam. . 2. Confirmation of weed prevention effect The amount of weeds generated during the cultivation period was compared. From Table 1,
Examples 1 and 2 and Comparative Examples 3 and 4 having a colored pulp layer
It can be seen that the function of suppressing the generation of weeds for blocking transmitted light is high. 3. Confirmation of growth-promoting effect The weight of cucumber fruited after cultivation was compared. From Table 1,
In the multi-sheet having the light reflection layer, the fruit is relatively large due to the light from the bottom of the fruit. In addition, there was no variation in the growth of each plant. 4. Confirmation of Mechanical Extensibility The multi-sheets obtained in Examples 1 and 2 and Comparative Examples 1 to 4 were extended on flat ridges, flat high ridges, and round ridges shown in FIG. ：: Good spread, no problem. ×: Unexpandable, tears on the way. From Table 1, it is understood that all the furrows can be handled by performing the stretching process.

[0023]

[Table 1]

[0024]

Industrial Applicability The paper multi-sheet of the present invention is a paper multi-sheet having a ground temperature suppressing effect and a plant growth promoting effect, a high weed prevention effect, and excellent machine spreading suitability.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a ridge obtained by performing a spreading test on multi-sheets of Examples 1 and 2 of the present invention and Comparative Examples 1 to 4 using a mulcher.

Claims (2)

[Claims] 1. A paper multi-sheet characterized by having a breaking elongation in the papermaking direction of 3 to 20% according to JIS P 8132, and comprising two layers of a light reflecting layer and a colored pulp layer. 2. The paper multi-sheet according to claim 1, wherein the colored pulp layer contains at least one selected from humic acid, humic acid salt and carbon black.