JP2005253454A - Agricultural sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prepare a biodegradable agricultural sheet excellent in antimicrobial effect and air permeability as well as soil temperature rise by coating and setting one side of a nonwoven fabric comprising cellulose rayon fiber of bamboo origin with charcoal powder soot. <P>SOLUTION: This agricultural sheet excellent in antimicrobial effect and biodegradability is obtained by simply applying charcoal powder soot onto one side of the nonwoven fabric containing ≥50 wt.% of the cellulose rayon fiber of bamboo origin and having a basis weight of 15-70 g/m<SP>2</SP>. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a biodegradable agricultural sheet that is antibacterial and increases the root temperature.

  Conventionally, what is called a mulch in which carbon black is kneaded into PVC is generally used as an agricultural sheet, and has been used for cultivation of strawberries, onions and the like. However, since PVC itself is a water-repellent film that does not have air permeability, when the soil temperature is clear, it will rise rapidly, leading to root rot. PVC is not biodegradable and can only be burned as a waste treatment. Although PVC does not generate dioxins by low-temperature combustion, it is difficult to process because it is flame retardant. In addition, when the rain continued, strawberries and others started to rot even on the mulch, and the product value was often impaired.

Therefore, JP-A-08-126440 proposes an agricultural sheet using a non-woven fabric instead of a film. Nonwoven fabrics are air permeable and soil temperature management is easy, but conversely, they have drawbacks such as poor drainage during heavy rains, and agricultural products are easily corroded, so they are only used in greenhouses.
JP-A-11-103696 proposes an agricultural sheet in which a metal salt of an organic compound is kneaded as an agricultural sheet having an antibacterial and antifungal function. However, it is not preferable to use a metal salt of an organic compound for an agricultural product whose primary priority is safety.

  On the other hand, cellulose rayon fiber made from bamboo was invented about 70 years ago. Japanese Patent Laid-Open No. 2001-115347 proposes a fabric using the same. Since the cellulose rayon fiber using this bamboo has antibacterial property in the fiber itself, Japanese Patent Application Laid-Open No. 2003-310721 proposes antibacterial property.

  Charcoal powder is applied to one side of a nonwoven fabric made of cellulose rayon fiber made from bamboo and fixed to provide a biodegradable agricultural sheet with excellent antibacterial and breathability as well as increased soil temperature.

In view of the above problems, the present inventors have intensively studied the production of non-woven fabric made of cellulose rayon fibers made from bamboo. As a result, cellulose rayon fibers made from bamboo contain 50% by weight or more. An agricultural sheet having a basis weight of 15 to 70 g / m ² coated with charcoal powder on one side of the nonwoven fabric has been found to have eliminated all the above-mentioned conventional defects, thereby completing the present invention.

  As an effect of the present invention, an agricultural sheet is produced industrially using cellulose rayon fibers made from bamboo obtained by the viscose rayon method by pulping bamboo, which is a representative wood with a short growth cycle on the earth. What can be made easily is extremely industrial. In addition, charcoal such as bamboo, cedar, pine, ume cocoon, and bamboo shoots is excellent in antibacterial properties, so it reinforces the antibacterial properties of cellulose rayon fibers made from bamboo. Yes, it is extremely safe. That is, the object of the present invention is to apply and fix a charcoal powder koji made of bamboo, cedar, pine, cocoon candy and bamboo shoots to a non-woven fabric using cellulose fiber made of bamboo, which is inexpensive, antibacterial and biodegradable. It is to provide industrially advantageous agricultural sheets.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail.
The cellulose rayon fiber made from bamboo in the present invention is not particularly limited. The proportion of cellulose rayon fiber made from bamboo as a raw material is 50% by weight or more, preferably 70% by weight or more. If the proportion of cellulose rayon fibers made from bamboo as a raw material is less than 50% by weight, even if charcoal powder is used in combination, the antibacterial properties are insufficient, which is not preferable. Other fibers used for the nonwoven fabric are preferably rayon fiber, cotton and polylactic acid fiber in view of biodegradability.

The kind of nonwoven fabric in this invention is not specifically limited. Since the main component is rayon fiber, the needle punch method or the spunlace method is mainly used, but the spunlace is preferable in terms of strength and cost. The basis weight of the nonwoven fabric is 15 to 70 g / m ² . If the basis weight of the nonwoven fabric is less than 15 g / m ² , it is not preferable from the viewpoint of the strength of the nonwoven fabric. When the basis weight of the nonwoven fabric exceeds 70 g / m ² , various functions reach saturation and the cost increases, which is not economical.

  The raw material of the charcoal powder lees applied to one side of the nonwoven fabric in the present invention is not particularly limited. Bamboo, cedar, pine, ume cocoons and firewood, which are often used as charcoal, are preferred in terms of cost. When charcoal charcoal is fired at a relatively low temperature of 600 to 800 ° C., it is better to use the charcoal to make antibacterial properties. There is no particular problem if the charcoal particle size is 2 microns or less. Gravure printing is good for attaching charcoal powder to non-woven fabric. It should be noted that there is no problem even if charcoal powder is applied and fixed on both sides of the nonwoven fabric, but the function of charcoal not only reaches saturation but also increases in cost.

The gist of the present invention is characterized in that the charcoal powder is applied to one side of a nonwoven fabric containing 50% by weight or more of cellulose rayon fiber made from bamboo and having a basis weight of 15 to 70 g / m ^2. Agricultural sheet.

  Furthermore, the nonwoven fabric contains 70% by weight or more of cellulose rayon fiber made from bamboo.

  And the nonwoven fabric is a spunlace nonwoven fabric.

  And the charcoal is a powdered rice cake of one kind or two kinds selected from bamboo, cedar, pine, eel rice cake and firewood.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited at all by these Examples.
・ Examples (1) to (5), Comparative Examples (1) to (5)

  Viscose rayon fiber made from bamboo from China (referred to as A fiber, fineness 1.7 decitex, fiber length 38 mm) and other fibers as shown in Table 1 [rayon fiber: B fiber, cotton fiber: C fiber, Lactron (polylactic acid fiber): D fiber, polyester fiber: E fiber. In each case, a fineness of 1.7 dtex and a fiber length of 38 mm] were added to make a nonwoven fabric.

-Biodegradability evaluation 1 g of nonwoven fabric was placed in standard compost and left for 50 days. (Decomposition rate 80% or more: ○, decomposition rate 50-80%: Δ, decomposition rate 50% or less: x)

-Antibacterial evaluation According to JIS L 1902: 2002 method. (The number of bacteria after 18 hours is 10 ⁶ or less: ○, 10 ⁶ to 10 ⁷ : Δ, 10 ⁷ or more: x initial number of bacteria 10 ⁵ )

・ Strength Used as an agricultural sheet in an outdoor field for 6 months. (No damage: ○, Some damage: △, Significant damage: ×)

As is clear from Table 1, the examples (1) to (8) have sufficient antibacterial properties, biodegradability, and nonwoven fabric strength, and are suitable as agricultural sheets.
Comparative Example (1) uses polyester fibers and is not preferable for biodegradability. In Comparative Example (2), the amount of regular rayon fibers is as high as 70%, and thus the antibacterial property is not good. The comparative example (3) is not preferable because the antibacterial property is insufficient because the nonwoven fabric is coated with carbon black. Comparative Example (4) is not only inferior in antibacterial properties due to the thin nonwoven fabric basis weight, but also lacks the strength of the nonwoven fabric. On the contrary, the comparative example (5) is not preferable because the basis weight is too large and the cost increases.

  As an agricultural seat, it can be safely used for all crops, both outdoors and indoors.

Claims (4)

Agricultural sheet in which charcoal powder is applied to one side of a nonwoven fabric containing 50% by weight or more of cellulose rayon fiber made from bamboo and having a basis weight of 15 to 70 g / m ² .   The agricultural sheet according to claim 1, which is a nonwoven fabric containing 70% by weight or more of cellulose rayon fiber made from bamboo.   The agricultural sheet according to claim 1, wherein the unemployed fabric is a spunlace nonwoven fabric.   2. The agricultural sheet according to claim 1, wherein the charcoal is one or two kinds of powdered rice cake selected from bamboo, cedar, pine, eel rice cake and bamboo shoots.